MiraLAX is an osmotic laxative. That means it draws water into the colon, which softens the stool and may naturally stimulate the colon to contract. These actions help ease bowel movements.
MiraLAX (polyethylene glycol 3350)
MiraLAX is a brand-name, over-the-counter (OTC) medication. It’s classified as an osmotic laxative.
MiraLAX is used to treat constipation. It’s typically used for short-term treatment, but in some cases, it’s used long-term to treat chronic (long-lasting) constipation. MiraLAX is also sometimes used for colonoscopy bowel preparation.
For most people, taking MiraLAX will cause a bowel movement within 1 to 3 days of taking it. One study of its effectiveness focused on people who had fewer than two bowel movements per week. MiraLAX increased their number of bowel movements to 4.5 per week, compared to 2.7 per week in people taking a placebo.
MiraLAX comes as a flavorless powder that you mix with 4 to 8 ounces of water, juice, or other liquid. The powder comes in bottles or single-serve packets.
MiraLAX dosage will depend on several factors. These include:
- the reason MiraLAX is being used
- the age of the person using MiraLAX
Typically, you should use the smallest dosage that provides the desired effect.
The following information describes dosages that are commonly used or recommended. If you’re unsure about what dosage to use, ask your doctor or pharmacist.
Dosage for kids, toddlers, and infants
Before giving MiraLAX to your child, talk with your child’s doctor. They can recommend the most appropriate dosage of MiraLAX for your child. The manufacturer of MiraLAX doesn’t provide this information. They advise getting a doctor’s recommendation for children’s dosage.
It’s also important to talk with your child’s doctor because they may want to evaluate your child to determine the cause of constipation. Depending on the cause, other treatments may be needed.
Dosage for adults
The typical dosage of MiraLAX for adults is 17 grams. The product will come with a measuring cap or device to help you determine the correct dose.
The powder is mixed and dissolved in 4 to 8 ounces of water or another beverage and consumed once daily.
What if I miss a dose?
If you miss a dose, take it as soon as you remember. If it’s almost time for your next dose, just take that one dose. Don’t try to catch up by taking two doses at once.
Will I need to use this drug long-term?
MiraLAX is intended for the short-term treatment of constipation. If you have chronic (long-lasting) constipation, you should be evaluated by your doctor. Your doctor will decide the best treatment for you, which may include long-term treatment with MiraLAX.
MiraLAX can cause mild or serious side effects. The following list contains some of the key side effects that may occur while taking MiraLAX. This list does not include all possible side effects.
For more information on the possible side effects of MiraLAX, or tips on how to manage with a troubling side effect, talk with your doctor or pharmacist.
More common side effects
The more common side effects of MiraLAX include:
- diarrhea or loose stools
- gas (flatulence)
- nausea
- stomach pain
- bloating
These side effects may go away within a few days or a couple of weeks. If they’re more severe or don’t go away, talk with your doctor or pharmacist.
Serious side effects
Call your doctor right away if you have serious side effects. Call 911 if your symptoms feel life threatening or if you think you’re having a medical emergency. Serious side effects and their symptoms can include the following:
- Dehydration. Diarrhea caused by MiraLAX can cause fluid loss and dehydration. Older adults have a higher risk of diarrhea and dehydration. Symptoms of dehydration include:
- thirst
- fatigue
- dizziness
- confusion
- dry mouth
- irritability
- no tears when crying (in children)
- no wet diapers for several hours (in children)
- rash
- itchy skin
- runny nose
- trouble breathing
- swollen lips, tongue, or throat
Diarrhea
Diarrhea or loose stools are side effects of MiraLAX. Diarrhea is more likely to happen if you take more than the recommended dosage. Seniors also have a higher risk of diarrhea.
In one study , about 11% of those taking MiraLAX for chronic constipation had diarrhea as a side effect. In older adults, about 13% had diarrhea. For those who have diarrhea, the dosage may need to be reduced.
Bloating
Some people who take MiraLAX have bloating. In one study , about 3% of people taking MiraLAX for chronic constipation had bloating as a side effect. This side effect may decrease or go away with continued use of MiraLAX.
Nausea
Some people who take MiraLAX have nausea. In one study , about 6% of people taking MiraLAX for chronic constipation had nausea as a side effect. This side effect may decrease or go away with continued use of MiraLAX.
Weight gain
Some people have said they gained weight while taking MiraLAX. However, it’s not clear if MiraLAX is the cause of weight gain.
Headache
Some people have said they had headaches while taking MiraLAX. However, it’s not clear if MiraLAX is the cause of headaches.
Long-term side effects
The short-term and long-term side effects of MiraLAX are similar. In a study lasting 12 months, the most common side effects of MiraLAX were:
- diarrhea or loose stools
- gas (flatulence)
- nausea
- stomach pain
- bloating
Side effects are more likely to occur in the first weeks of MiraLAX use and may decrease over time.
Side effects in children
The same side effects that occur in adults can also happen in children.
There’s also some concern about other safety problems in children who take MiraLAX. There have been reports to the Food and Drug Administration (FDA) about unusual side effects in some children, such as:
- anger
- aggression
- mood swings
- tremors
- seizure
The FDA found that MiraLAX may contain small amounts of chemicals such as ethylene glycol that could cause these side effects if ingested in large amounts. However, a study funded by the FDA found that children taking MiraLAX did not have higher levels of these chemicals in their blood compared to children who weren’t taking MiraLAX.
These side effects have not occurred in clinical studies of MiraLAX in children, and it’s not clear if they’re caused by MiraLAX or something else. The FDA is funding additional research to investigate the concerns.
Despite these concerns, the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition continues to consider MiraLAX a first-choice medication for short- and long-term treatment of constipation in children.
If you have concerns about these side effects, talk with your doctor.
MiraLAX contains the ingredient polyethylene glycol 3350 (PEG 3350).
MiraLAX is also available in generic versions, which are usually store brands. These store brands often cost less than brand-name MiraLAX.
MiraLAX is approved for over-the-counter (OTC) use in adults and adolescents aged 17 years and older.
It’s also effective for treating constipation in younger children, including babies younger than 2 years of age.
According to the North American Society of Pediatric Gastroenterology, MiraLAX is a first-choice medication for treating and preventing constipation in children. However, it shouldn’t be used in young children without the direction of your child’s doctor.
MiraLAX only comes as a powder. You mix MiraLAX powder into 4 to 8 ounces of water or another beverage and drink it as a liquid. MiraLAX itself doesn’t come in a liquid form. It also doesn’t come as a tablet or pill.
Bottles of MiraLAX powder contain either 7 doses, 14 doses, 30 doses, or 45 doses. Also available are boxes containing single-serve packets of MiraLAX powder. The boxes contain 10 or 20 packets each.
According to the American Gastroenterological Association, MiraLAX is considered a first-choice laxative for use during pregnancy. This means it’s safe to use MiraLAX while you’re pregnant.
Although human studies have not evaluated MiraLAX during pregnancy, it’s known that very little MiraLAX is absorbed by the body. Therefore, it’s unlikely the drug will affect a fetus if taken by a pregnant person. In studies of pregnant animals given MiraLAX, no harm to a fetus was found.
According to the American Gastroenterological Association, MiraLAX is considered low-risk for use during breastfeeding.
Although human studies have not evaluated MiraLAX during breastfeeding, it’s known that very little MiraLAX is absorbed by the body. Therefore, it’s unlikely the drug would affect a child who is breastfed if it’s taken by a person who is lactating.
MiraLAX is an over-the-counter (OTC) drug that’s approved by the Food and Drug Administration (FDA) for certain purposes.
Recommended uses for MiraLAX
MiraLAX is approved for treating short-term constipation. It’s also recommended for other uses.
MiraLAX for constipation
MiraLAX is approved for the short-term treatment of constipation in adults and adolescents aged 17 years and older.
Your doctor may also recommend it for treating constipation in younger children, including babies younger than 2 years of age.
Don’t take MiraLAX for more than 7 days without talking with your doctor. Your doctor may want to evaluate the cause of your constipation. Your doctor may find that you need other treatments.
MiraLAX is often recommended by doctors for treating chronic (long-lasting) constipation. The American College of Gastroenterology and the American Society of Colon and Rectal Surgeons recommend MiraLAX as an effective first-choice treatment for chronic constipation.
MiraLAX for colonoscopy prep
MiraLAX may be recommended by your doctor for colonoscopy bowel preparation. This is a procedure to clear out the contents of your gastrointestinal tract before you have a colonoscopy. According to one study, using MiraLAX is effective for this use, but may not be as effective as other options.
If your doctor recommends MiraLAX for bowel prep, you’ll be given specific instructions on how to use it. You may also need to take other medications for this purpose.
MiraLAX for IBS
MiraLAX is sometimes used by people with irritable bowel syndrome (IBS) who have constipation. MiraLAX may improve symptoms of constipation, but it hasn’t been found to improve other symptoms of IBS, such as stomach upset or pain.
MiraLAX for diverticulitis
Some people with diverticulitis also have constipation. If you have diverticulitis and constipation, talk with your doctor. Your doctor may recommend MiraLAX or other laxative options for your constipation. You may also need other treatments.
Uses that are not recommended
Not all potential uses for MiraLAX are recommended.
MiraLAX for weight loss
Some people take laxatives, including MiraLAX, with the intention of losing weight. However, MiraLAX and other laxatives are not effective for weight loss. In addition, they may cause harmful side effects if they’re used inappropriately. These can include diarrhea, dehydration, and electrolyte imbalances.
If you would like to lose weight, don’t use MiraLAX for that purpose. Instead, talk with your doctor about weight-loss approaches that can work well for you.
Take MiraLAX according to the instructions on the package or according to the directions you’ve received from your doctor.
Timing
MiraLAX can be taken at any time of the day. However, it may be best to take it in the morning. That way, if it causes you to have a bowel movement, you’ll be able to go during the day rather than during the night. You should only take MiraLAX once a day, unless your doctor gives you different instructions.
Taking MiraLAX with food
MiraLAX can be taken with or without food.
Your doctor may recommend MiraLAX for colonoscopy bowel preparation. This is a procedure that’s used to clear out the contents of your gastrointestinal tract before you have a colonoscopy. For this purpose, MiraLAX is sometimes used by itself or in combination with other laxatives.
If your doctor would like you to use MiraLAX for bowel prep, they’ll recommend a specific way to use it. Be sure to follow your doctor’s instructions. To give you an idea of what they might be like, here’s an example of bowel prep instructions:
- The day before your colonoscopy:
- Begin a clear liquid diet.
- At 12 pm (noon), take two laxative tablets such as Dulcolax. Also at this time, mix 8.3 ounces of MiraLAX in 64 ounces of a liquid such as Gatorade. This mixture should be refrigerated.
- At 5:00 pm, drink an 8-ounce glass of the MiraLAX-Gatorade mixture. Do this every 15 minutes until you’ve consumed a total of four 8-ounce glasses of the mixture (total of 32 ounces).
- When there are 5 hours before the procedure, drink the remaining 32 ounces of the MiraLAX-Gatorade mixture.
- Then, 2 hours before the procedure, stop all eating and drinking.
Bowel prep procedures will cause diarrhea. Therefore, you should stay near a toilet as you conduct the procedure.
MiraLAX is classified as an osmotic laxative. This means that it works by drawing water into the colon. The water softens the stool and may naturally stimulate the colon to contract. These actions help ease bowel movements.
How long does it take to work?
MiraLAX doesn’t usually cause a bowel movement immediately after it’s taken. For most people, it causes a bowel movement within one to three days after it’s taken. (The timing will be different if it’s used for colonoscopy bowel prep, as described above).
MiraLAX is an osmotic laxative used to treat constipation. There are other osmotic laxatives, and other types of laxatives, that can also be used to treat constipation. Examples of these laxatives include:
- Osmotic laxatives. These products work by drawing water into the colon (large intestine), which softens the stool and can cause the colon to contract. These effects help to produce a bowel movement. Examples of osmotic laxatives include:
- lactulose (Enulose, Kristalose)
- magnesium citrate
- magnesium hydroxide (Milk of Magnesia)
- calcium polycarbophil (FiberCon, Fiber-Lax)
- wheat dextrin (Benefiber)
- methylcellulose (Citrucel)
- psyllium (Konsyl, Metamucil, others)
- docusate (Colace, Kao-Tin, Surfak, others)
- bisacodyl (Dulcolax, others)
- senna (Ex-Lax, Senokot, others)
MiraLAX and Metamucil are both laxatives, but they work in different ways.
MiraLAX is an osmotic laxative. That means it draws water into the colon, which softens the stool and may naturally stimulate the colon to contract. These actions help ease bowel movements.
Metamucil is a psyllium fiber supplement that works as a bulk-forming laxative. Like osmotic laxatives, Metamucil draws water into the colon and makes the stool softer. However, in addition to that, its fiber content bulks up the stool, which naturally stimulates movement of the colon to pass the stool.
Uses
MiraLAX is used for short-term treatment of constipation and long-term treatment of chronic constipation. It’s also used for bowel prep before colonoscopy.
Metamucil is primarily used for preventing constipation. However, it may also be used for short-term treatment of constipation, as well as long-term treatment of chronic constipation. Metamucil is also used to help treat diarrhea, irritable bowel syndrome (IBS), diverticulosis, and high cholesterol.
Drug forms
MiraLAX comes as a powder in bottles and single-serve packets. You mix the powder with 4 to 8 ounces of liquid and drink it once daily.
Metamucil is available as a powder and as a capsule. You mix the powder with 8 ounces of water and drink it one to three times daily. For the capsule, you typically take two to five capsules up to four times daily.
Side effects and risks
MiraLAX and Metamucil have very similar common side effects. These can include:
- diarrhea or loose stools
- stomach pain
- bloating
- gas (flatulence)
- nausea
Some people may have more gas or bloating with Metamucil compared to MiraLAX. However, this side effect may decrease or go away with continued use of either product.
Taking Metamucil without adequate liquid can cause choking. Be sure to take Metamucil with at least 8 ounces of liquid. If you have swallowing problems, don’t take Metamucil.
Effectiveness
MiraLAX and Metamucil are both effective for treating constipation, but they have not been compared in clinical studies.
Guidelines from the American College of Gastroenterology and American Society of Colon and Rectal Surgeons recommend increasing dietary fiber or using fiber supplements such as Metamucil as a first-choice option to prevent and treat constipation, including chronic constipation.
They also recommend osmotic laxatives such as MiraLAX for treating constipation, including chronic constipation.
Both MiraLAX and Metamucil usually take 1 to 3 days to cause a bowel movement.
MiraLAX is an osmotic laxative. That means it draws water into the colon, which softens the stool and may naturally stimulate the colon to contract. These actions help ease bowel movements.
Dulocolax (bisacodyl) is a stimulant laxative. It works by irritating the intestines and causing them to contract. It also works by increasing water in the intestines. Both of these actions help cause a bowel movement.
Uses
MiraLAX is used for short-term treatment of constipation and long-term treatment of chronic constipation. It’s also used for bowel prep before colonoscopy.
Dulcolax is used for short-term treatment of constipation. It should not be used long-term. Dulcolax may also be used in combination with other laxatives (including MiraLAX) for bowel prep before colonoscopy or other procedures.
Drug forms
MiraLAX comes as a powder in bottles and single-serve packets. You mix the powder with 4 to 8 ounces of liquid and drink it once daily.
Dulcolax comes as tablets and rectal suppositories. Both forms are used once per day.
Side effects and risks
Common side effects from both MiraLAX and Dulcolax include:
- diarrhea or loose stools
- bloating
- gas (flatulence)
- nausea
The following side effects can occur with both MiraLAX and Dulcolax, but are more common with Dulcolax:
- stomach pain
- cramping
- vomiting
- diarrhea
- electrolyte problems such as low potassium
Stimulant laxatives, including Dulcolax, are also more likely to cause laxative dependence when taken long-term. This can cause severe constipation when the medication is stopped. (With dependence, your body needs the drug to feel like you usually do.)
Effectiveness
MiraLAX and Dulcolax are both effective for treating constipation. However, their effectiveness hasn’t been compared in clinical studies.
Guidelines from the American College of Gastroenterology and the American Society of Colon and Rectal Surgeons recommend osmotic laxatives such as MiraLAX for treating constipation, including chronic constipation.
Dulcolax is considered a second-choice option for short-term treatment of constipation. Also, it shouldn’t be used long-term.
Another difference is how long these products take to work. MiraLAX usually takes 1 to 3 days to cause a bowel movement. Dulcolax tablets, on the other hand, usually cause a bowel movement within 6 to 12 hours. And Dulcolax suppositories typically do so within 15 minutes to an hour.
You may wonder how certain products compare to MiraLAX. Below are comparisons between MiraLAX and several other treatments.
MiraLAX vs. Colace
MiraLAX is an osmotic laxative. That means it draws water into the colon, which softens the stool and may naturally stimulate the colon to contract. These actions help ease bowel movements.
Colace is a stool softener. It helps to draw water into the stool itself to make it softer and easier to pass. It doesn’t stimulate a bowel movement, as many laxatives do.
Uses
MiraLAX is used for short-term treatment of constipation and long-term treatment of chronic constipation. It’s also used for bowel prep before colonoscopy.
Colace is used short-term to prevent and to treat constipation. It’s not currently recommended for long-term treatment of chronic constipation. Colace is commonly used after surgical procedures to help prevent constipation.
Drug forms
MiraLAX comes as a powder in bottles and single-serve packets. You mix the powder with 4 to 8 ounces of liquid and drink it once daily.
Colace comes as a capsule you typically take twice daily.
Side effects and risks
Common MiraLAX side effects include:
- diarrhea or loose stools
- stomach pain
- bloating
- gas (flatulence)
- nausea
Colace doesn’t commonly cause side effects. In some cases, it causes loose stools. Diarrhea is considered a rare side effect.
Effectiveness
MiraLAX and Colace are both effective for treating constipation. However, their effectiveness hasn’t been compared in clinical studies.
Guidelines from the American College of Gastroenterology and the American Society of Colon and Rectal Surgeons recommend osmotic laxatives, including MiraLAX, for treating constipation, including chronic constipation.
Although Colace is very commonly used to treat constipation, these guidelines don’t recommend it for this use due to a lack of evidence showing benefit.
Both MiraLAX and Colace usually take 1 to 3 days to cause a bowel movement.
MiraLAX vs. milk of magnesia
MiraLAX is an osmotic laxative. That means it draws water into the colon, which softens the stool and may naturally stimulate the colon to contract. These actions help ease bowel movements.
Milk of magnesia (Phillip’s Milk of Magnesia and others) is another name for magnesium hydroxide. It works like an osmotic laxative.
Uses
MiraLAX is used for short-term treatment of constipation and long-term treatment of chronic constipation. It’s also used for bowel prep before colonoscopy.
Milk of magnesia is used for short-term treatment of constipation. It’s not currently recommended for long-term treatment of chronic constipation.
Drug forms
MiraLAX comes as a powder in bottles and single-serve packets. You mix the powder with 4 to 8 ounces of liquid and drink it once daily.
Milk of magnesia is the liquid form of magnesium hydroxide. Milk of magnesia products come as liquid suspensions. They’re usually taken once daily, but may be taken more often if needed.
Magnesium hydroxide products also come as oral tablets or caplets that are typically taken once daily.
Side effects and risks
Common side effects of MiraLAX include:
- diarrhea or loose stools
- stomach pain
- bloating
- gas (flatulence)
- nausea
Milk of magnesia and other magnesium hydroxide products can cause the same side effects as MiraLAX, as well as:
- cramping
- vomiting
- chalky taste
If you have kidney problems, you should not use milk of magnesia or other magnesium hydroxide products. These products can cause high magnesium levels in the body, which can cause dangerous side effects such as:
- muscle weakness
- low blood pressure
- confusion
- heart rhythm changes
Effectiveness
An analysis of studies comparing MiraLAX and milk of magnesia for constipation in children found conflicting results. Some of these studies show that MiraLAX might be slightly more effective than milk of magnesia. However, another study in the analysis found that milk of magnesia may be more effective.
Guidelines for treating constipation in children recommend MiraLAX as a first choice for short- and long-term treatment of constipation. Milk of magnesia is considered a second-choice option.
For adults, guidelines from the American College of Gastroenterology and the American Society of Colon and Rectal Surgeons recommend osmotic laxatives such as MiraLAX for treating constipation, including chronic constipation.
Even though milk of magnesia and other magnesium hydroxide products are very commonly used for treating constipation in adults, these guidelines don’t recommend them for this purpose because there’s not a lot of evidence showing benefit.
Another difference between MiraLAX and milk of magnesia is how long they take to work. MiraLAX usually takes 1 to 3 days to cause a bowel movement. Milk of magnesia, on the other hand, usually causes a bowel movement within 30 minutes to 6 hours.
MiraLAX vs. Benefiber
MiraLAX and Benefiber are both laxatives but work in different ways.
MiraLAX is an osmotic laxative. That means it draws water into the colon, which softens the stool and may naturally stimulate the colon to contract. These actions help ease bowel movements.
Benefiber is a wheat dextrin fiber supplement that works as a bulk-forming laxative. Like osmotic laxatives, Benefiber draws water into the colon and makes the stool softer. However, in addition to that, its fiber content bulks up the stool, which naturally stimulates movement of the colon to pass the stool.
Uses
MiraLAX is used for short-term treatment of constipation and long-term treatment of chronic constipation. It’s also used for bowel prep before colonoscopy.
Benefiber is primarily used for preventing constipation. However, it may also be used for short-term treatment of constipation, as well as long-term treatment of chronic constipation.
Drug forms
MiraLAX comes as a powder in bottles and single-serve packets. You mix the powder with 4 to 8 ounces of liquid and drink it once daily.
Benefiber comes as a bulk powder and in single-serving packets. The powder is mixed with 4 to 8 ounces of water or another non-carbonated beverage and taken 1 to 3 times daily. It can also be mixed into soft foods such as yogurt, pudding, or applesauce.
Side effects and risks
MiraLAX and Benefiber have very similar common side effects. These can include:
- diarrhea or loose stools
- stomach pain
- bloating
- gas (flatulence)
- nausea
People with gluten intolerance may want to avoid using Benefiber. This is because Benefiber contains wheat dextrin. The manufacturer says that it contains less than 20 ppm of gluten.
Effectiveness
MiraLAX and Benefiber are both effective for treating constipation. However, no clinical studies have directly compared their effectiveness.
Guidelines from the American College of Gastroenterology and the American Society of Colon and Rectal Surgeons recommend increasing dietary fiber or using fiber supplements such as Benefiber as a first-choice treatment to prevent and treat constipation, including chronic constipation.
They also recommend osmotic laxatives such as MiraLAX for treating constipation, including chronic constipation.
Both MiraLAX and Benefiber usually take 1 to 3 days to cause a bowel movement.
MiraLAX vs. Lactulose
Both MiraLAX and lactulose are osmotic laxatives. They work by drawing water into the colon, which softens the stool and can naturally cause the colon to contract. These actions help ease bowel movements.
MiraLAX is available over-the-counter. Lactulose requires a prescription from your doctor.
Uses
MiraLAX is used for short-term treatment of constipation and long-term treatment of chronic constipation. It’s also used for bowel prep before colonoscopy.
Lactulose is used for short-term treatment of constipation and long-term treatment of chronic constipation. Lactulose is also used for people with severe liver disease who have a condition called hepatic encephalopathy.
Drug forms
MiraLAX comes as a powder in bottles and single-serve packets. You mix the powder with 4 to 8 ounces of liquid and drink it once daily.
Lactulose comes as an oral solution and as a powder that you mix with water and drink. You take either form once daily.
Side effects and risks
MiraLAX and lactulose have very similar common side effects. These can include:
- diarrhea or loose stools
- stomach pain
- bloating
- gas (flatulence)
- nausea
These side effects may be more common with lactulose. Lactulose may also be more likely to cause electrolyte imbalances as a result of diarrhea. Decreasing the dosage of lactulose may reduce these side effects.
Effectiveness
MiraLAX and lactulose are both effective for treating constipation. Both usually take 1 to 3 days to cause a bowel movement.
Guidelines from the American College of Gastroenterology and the American Society of Colon and Rectal Surgeons recommend osmotic laxatives such as these products for treating constipation, including chronic constipation, in adults.
An analysis of studies in children with constipation found that MiraLAX may be more effective than lactulose for increasing bowel movements.
Guidelines for treating constipation in children recommend MiraLAX as a first-choice option for short- and long-term treatment of constipation. Lactulose is considered a second-choice option.
MiraLAX vs. GoLytely
MiraLAX and GoLytely are both osmotic laxatives. That means they draw water into the colon, which softens the stool and may naturally stimulate the colon to contract. These actions help ease bowel movements.
MiraLAX and GoLytely also contain the same main ingredient, polyethylene glycol. In addition, GoLytely contains the electrolytes potassium and sodium.
MiraLAX is an over-the-counter, brand-name product. GoLytely requires a prescription from your doctor.
Uses
MiraLAX is used for short-term treatment of constipation and long-term treatment of chronic constipation. It’s also used for bowel prep before colonoscopy.
GoLytely is only used for bowel prep before colonoscopy or other procedures.
Drug forms
MiraLAX comes as a powder in bottles and single-serve packets. You mix the powder with 4 to 8 ounces of liquid and drink it once daily when used for constipation. When used for bowel prep, larger doses are taken over a period of 2 days.
GoLytely comes as a powder in a large 4-liter jug. You need to add water to the jug, and then drink the solution as part of a bowel preparation procedure.
Side effects and risks
MiraLAX and GoLytely share some similar side effects, but GoLytely also has additional effects.
More common side effects
Using MiraLAX and GoLytely for bowel prep before colonoscopy or other procedures can cause similar common side effects, such as:
- bloating
- stomach pain
- nausea
- thirst
Loose stools and diarrhea are expected to occur with bowel prep procedures.
Serious side effects
Although uncommon, some serious side effects have happened in people using GoLytely bowel preparation, such as:
- electrolyte imbalances, resulting in seizures or heart arrhythmias
- fluid retention
- dehydration
- kidney problems
- ischemic colitis (inflammation of the colon)
Other considerations
If you have certain health problems, your doctor may do special tests before prescribing GoLytely. Or, they may recommend other products. These health problems include:
- heart arrhythmia
- heart failure
- seizures
- kidney problems
- ulcerative colitis
- blockage in the intestine
Effectiveness
MiraLAX and GoLytely have been directly compared in clinical studies. In one study, GoLytely was more effective than MiraLAX mixed with Gatorade for bowel cleansing before colonoscopy.
In another study , a combination of MiraLAX in Gatorade plus Dulcolax worked as well as GoLytely for bowel cleansing before colonoscopy.
More research is needed to know whether one medication works better for everyone.
MiraLAX vs. Citrucel
MiraLAX and Citrucel are both laxatives but work in different ways.
MiraLAX is an osmotic laxative. That means it draws water into the colon, which softens the stool and may naturally stimulate the colon to contract. These actions help ease bowel movements.
Citrucel is a methylcellulose fiber supplement that works as a bulk-forming laxative. Like osmotic laxatives, Citrucel draws water into the colon and makes the stool softer. In addition to that, its fiber content bulks up the stool, which naturally stimulates movement of the colon to pass the stool.
Uses
MiraLAX is used for short-term treatment of constipation and long-term treatment of chronic constipation. It’s also used for bowel prep before colonoscopy.
Citrucel is primarily used for preventing constipation. However, it may also be used for short-term treatment of constipation, as well as long-term treatment of chronic constipation.
Drug forms
MiraLAX comes as a powder in bottles and single-serve packets. You mix the powder with 4 to 8 ounces of liquid and drink it once daily.
Citrucel is available as a bulk powder and in caplets (coated oval tablets). You mix the powder with 8 ounces of liquid and drink it one to three times daily. You take the caplet one to six times daily.
Side effects and risks
MiraLAX and Citrucel have very similar common side effects. These can include:
- diarrhea or loose stools
- stomach pain or bloating
- gas or flatulence
- nausea
These side effects may decrease or go away with continued use of the products.
Taking Citrucel without adequate liquid can cause choking. Be sure to take Citrucel with at least eight ounces of liquid. If you have swallowing problems, don’t take Citrucel.
Effectiveness
MiraLAX and Citrucel are both effective for constipation. Both products usually take 1 to 3 days to cause a bowel movement.
Guidelines from the American College of Gastroenterology and the American Society of Colon and Rectal Surgeons recommend increasing dietary fiber or using fiber supplements such as Citrucel as a first-choice option to prevent and treat constipation, including chronic constipation.
The guidelines also recommend osmotic laxatives such as MiraLAX for treating constipation, including chronic constipation.
MiraLAX vs. PediaLax
MiraLAX is an osmotic laxative. That means it draws water into the colon, which softens the stool and may naturally stimulate the colon to contract. These actions help ease bowel movements.
PediaLax (magnesium hydroxide) reduces acid levels in the stomach. It also works like an osmotic laxative. It draws water into the colon, which softens the stool and can naturally stimulate the colon to contract. These effects help produce a bowel movement. (This comparison addresses only the chewable tablet form of PediaLax.)
Uses
MiraLAX is used for short-term treatment of constipation and long-term treatment of chronic constipation. It’s also used for bowel prep before colonoscopy.
MiraLAX is approved for over-the-counter use in adults and children aged 17 years and older. When recommended or prescribed by a doctor, it may also be used in younger children with ages ranging from under 2 years to 16 years.
PediaLax is used for short-term treatment of constipation. It’s not recommended for long-term treatment of chronic constipation.
PediaLax is approved for over-the-counter use in children ages 2 to 11 years.
Drug forms
MiraLAX comes as a powder in bottles and single-serve packets. You mix the powder with 4 to 8 ounces of liquid and drink it once daily.
PediaLax comes as a chewable tablet that may be taken one to six times daily, depending on the child’s age.
Side effects and risks
Common side effects of MiraLAX include:
- diarrhea or loose stools
- stomach pain or bloating
- gas or flatulence
- nausea
PediaLax can cause the same side effects as MiraLAX, as well as:
- cramping
- vomiting
- chalky taste
If your child has kidney problems, they should not use PediaLax. This product can cause high magnesium levels in the body, which can cause dangerous side effects such as:
- muscle weakness
- low blood pressure
- confusion
- heart rhythm changes
Effectiveness
MiraLAX and PediaLax are both effective for treating constipation in children. According to the North American Society of Pediatric Gastroenterology, MiraLAX is a first-choice medication for treating and preventing constipation in children.
Products that contain magnesium hydroxide, such as PediaLax, are recommended as second-choice options.
Another difference between the two products is how long they take to work. MiraLAX usually takes 1 to 3 days to cause a bowel movement. PediaLax, on the other hand, usually causes a bowel movement within 30 minutes to 6 hours.
Before giving MiraLAX or PediaLax to your child, talk with your child’s doctor. They may want to evaluate your child to determine the cause of constipation. Depending on the cause, other treatments may be needed.
If you’re taking MiraLAX to treat or prevent constipation, you should avoid drinking alcohol. Drinking alcohol, especially excessive drinking, can cause stomach problems and might worsen side effects caused by MiraLAX, such as:
- diarrhea
- stomach pain
- bloating
- dehydration
- nausea
If you’re using MiraLAX for bowel prep before colonoscopy or another procedure, you shouldn’t drink alcohol. Bowel prep procedures usually allow alcohol-containing drinks.
MiraLAX can interact with several other medications. You may also wonder how it might interact with fiber and certain foods.
MiraLAX and other medications
Below are lists of medications that can interact with MiraLAX. This article does not contain all drugs that may interact with MiraLAX.
Different drug interactions can cause different effects. For instance, some can interfere with how well a drug works, while others can cause increased side effects.
Before taking MiraLAX, be sure to tell your doctor and pharmacist about all prescription, over-the-counter, and other drugs you take. Also tell them about any vitamins, herbs, and supplements you use. Sharing this information can help you avoid potential interactions.
If you have questions about drug interactions that may affect you, ask your doctor or pharmacist.
Diuretics
MiraLAX and other laxatives can sometimes cause electrolyte imbalances. Certain diuretics can also cause these problems. Taking laxatives with diuretics might increase the risk of serious side effects caused by electrolyte imbalances, such as muscle weakness and heart rhythm problems.
Examples of these diuretics include:
- furosemide (Lasix)
- bumetanide (Bumex)
- torsemide (Demadex)
Drugs that prolong the QT interval
Certain medications prolong your QT interval, which means they might affect the rhythm of your heartbeat.
Although it’s not common, MiraLAX and other laxatives can cause electrolyte imbalances. These imbalances can increase the risk of a serious heart arrhythmia in people who have a prolonged QT interval. If you have electrolyte imbalances caused by MiraLAX or other laxatives, you should not take medications that prolong the QT interval.
Examples of these medications include:
- amiodarone (Pacerone)
- antipsychotic medications such as pimozide (Orap), haloperidol, quetiapine (Seroquel, Seroquel XR), and ziprasidone (Geodon)
- macrolide antibiotics such as erythromycin (Ery-Tab)
- quinidine
- procainamide
- tricyclic antidepressants such as amitriptyline, desipramine (Norpramin), and imipramine (Tofranil)
- sotalol (Sotylize, Betapace, Betapace AF, Sorine)
Oral medications
You shouldn’t take oral medications (drugs you take by mouth) during the hour before you use MiraLAX for bowel prep before colonoscopy or other procedures. MiraLAX bowel prep procedures may decrease the amount of these drugs that your body absorbs.
MiraLAX and fiber
Many people take daily fiber products to prevent constipation or for general digestive health. Fiber products are usually a first choice for preventing and treating constipation.
When fiber alone isn’t enough for preventing or treating constipation, MiraLAX may be taken along with it until constipation goes away.
MiraLAX and foods
MiraLAX powder should be added to 4 to 8 ounces of water or other liquids. These other liquids can include milk or coffee.
MiraLAX and milk
MiraLAX can be mixed with and consumed in milk. Be sure to mix it with at least 4 to 8 ounces of milk.
MiraLAX in coffee
MiraLAX can be mixed with and consumed in coffee. Be sure to mix it with at least 4 to 8 ounces of coffee.
Here are answers to some common questions about MiraLAX.
Is MiraLAX a stool softener?
MiraLAX is classified as an osmotic laxative, not a stool softener. However, both products do soften the stool. Osmotic laxatives do this by drawing water into the colon (large intestine). Stool softeners do it by drawing water into the stool itself.
Is MiraLAX a laxative?
Yes, MiraLAX is a laxative. It’s called an osmotic laxative. This means it works by drawing water into the colon. The water softens the stool and may naturally stimulate the colon to contract. These actions help ease bowel movements.
MiraLAX is not a stimulant laxative.
Is MiraLAX fiber?
No, MiraLAX is not fiber.
Can I take MiraLAX with fiber?
Yes, you can take MiraLAX with fiber. Many people take fiber daily to prevent constipation and for general digestive health. Fiber products are usually a first choice for preventing and treating constipation.
When fiber isn’t enough for preventing or treating constipation, MiraLAX may also be taken until constipation goes away.
How fast does MiraLAX work?
MiraLAX usually causes a bowel movement within 1 to 3 days.
Is it safe to use MiraLAX long-term?
Over-the-counter MiraLAX and other laxatives are usually only recommended for short-term use, up to a week.
If your constipation lasts longer than a week, you should contact your doctor. Your doctor may want to evaluate the cause of your constipation. Depending on the cause, your doctor may recommend long-term use of MiraLAX or other treatments.
Does MiraLAX come in a prescription form?
MiraLAX is not available in prescription form. Similar products such as GoLytely are available by prescription from a doctor.
Is MiraLAX safe for use after surgery?
MiraLAX is sometimes used after surgery to prevent and treat constipation. However, if you’ve had surgery and are having constipation, talk with your doctor. Your doctor may want to evaluate the cause of your symptoms. Depending on the cause, your doctor may recommend MiraLAX or other treatments.
Taking too much MiraLAX can increase your risk of side effects.
Overdose symptoms
Symptoms of an overdose can include:
- bloating
- stomach pain
- nausea
- excessive diarrhea
- dehydration
- electrolyte imbalances
- thirst
What to do in case of overdose
If you think you’ve taken too much of this drug, call your doctor or seek guidance from America’s Poison Centers at 800-222-1222 or through its online tool. But if your symptoms are severe, call 911 or go to the nearest emergency room right away.
Before taking MiraLAX, talk with your doctor about your health history. MiraLAX may not be appropriate for you if you have certain medical conditions.
- For people with kidney disease: Although it’s not common, MiraLAX and other laxatives can cause electrolyte imbalances. This problem can be worse in people with kidney disease. If you have kidney disease, talk with your doctor before using MiraLAX or other laxatives.
- For people with stomach problems: If you have stomach problems such as nausea, vomiting, bloating, or stomach pain, talk with your doctor before using MiraLAX or other laxatives. Your doctor may need to evaluate the cause of your symptoms to see if MiraLAX or other laxatives are safe for you.
- For people with irritable bowel syndrome (IBS): MiraLAX and other laxatives may worsen some symptoms of IBS. If you have IBS, talk with your doctor before taking MiraLAX or other laxatives.
- For people with swallowing problems: MiraLAX may cause choking when used by people with swallowing problems. If you have swallowing problems, talk with your doctor before using MiraLAX.
Each MiraLAX package is given an expiration date by the manufacturer of the product. This date is printed on the package. The purpose of the expiration date is to guarantee the effectiveness of the medication during this time.
The current stance of the Food and Drug Administration (FDA) is to avoid using expired medications. However, an FDA study showed that many medications may still be good beyond the expiration date listed on the bottle.
How long a medication remains good can depend on many factors, including how and where the medication is stored. MiraLAX should be stored at room temperature in its original container.
If you have unused medication that has gone past the expiration date, talk with your pharmacist about whether you might still be able to use it.
The following information is provided for clinicians and other healthcare professionals.
Mechanism of action
MiraLAX is an osmotic laxative. In the gastrointestinal tract, it retains water in the colon and within the stool. The increased water in the colon may also naturally stimulate contraction. MiraLAX increases stool weight, softens the stool, and increases stool frequency.
Pharmacokinetics and metabolism
When taken orally, less than 0.2 percent of MiraLAX is absorbed through the gastrointestinal tract. The remainder of the oral dose is recovered in the stool. MiraLAX is not fermented or metabolized in the gastrointestinal tract.
Contraindications
MiraLAX is contraindicated in patients with:
- known or suspected gastrointestinal obstruction
- known hypersensitivity to polyethylene glycol
Storage
MiraLAX should be stored at room temperature, 68°F to 77°F, in its original container.
Disclaimer: Medical News Today has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.
- Constipation
- GastroIntestinal / Gastroenterology
- Pharmacy / Pharmacist
- Drugs
MiraLAX
Medically reviewed by Sanjai Sinha, MD. Last updated on Jun 14, 2021.
What is MiraLAX?
MiraLAX is a laxative solution that increases the amount of water in the intestinal tract to stimulate bowel movements.
MiraLAX is used as a laxative to treat occasional constipation or irregular bowel movements.
MiraLAX may also be used for purposes not listed in this medication guide.
Important information about MiraLAX
You should not use MiraLAX if you have a bowel obstruction or intestinal blockage. If you have any of these conditions, you could have dangerous or life-threatening side effects from MiraLAX.
People with eating disorders (such as anorexia or bulimia) should not use MiraLAX without the advice of a doctor.
Before taking MiraLAX, tell your doctor if you are allergic to any drugs, or if you have ulcerative colitis, irritable bowel syndrome, kidney disease, nausea or vomiting with severe stomach pain, or if you have had a sudden change in bowel habits that has lasted 2 weeks or longer.
MiraLAX should produce a bowel movement within 1 to 3 days of using the medication. Polyethylene glycol 3350 normally causes loose or even watery stools.
Do not use MiraLAX more than once per day. Call your doctor if you are still constipated or irregular after using this medication for 7 days in a row.
Before taking this medicine
You should not use MiraLAX if you are allergic to polyethylene glycol, or if you have a bowel obstruction or intestinal blockage. If you have any of these conditions, you could have dangerous or life-threatening side effects from polyethylene glycol 3350.
People with eating disorders (such as anorexia or bulimia) should not use this medication without the advice of a doctor.
To make sure this medicine is safe for you, tell your doctor if you have:
- nausea, vomiting, or severe stomach pain;
- ulcerative colitis;
- irritable bowel syndrome;
- kidney disease; or
- if you have had a sudden change in bowel habits that has lasted 2 weeks or longer.
FDA pregnancy category C. It is not known whether MiraLAX will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant while using this medication.
It is not known whether polyethylene glycol 3350 passes into breast milk or if it could harm a nursing baby. Tell your doctor if you are breast-feeding a baby.
How should I take MiraLAX?
Use MiraLAX exactly as directed on the label, or as it has been prescribed by your doctor. Do not use this medicine in larger or smaller amounts or for longer than recommended.
To use MiraLAX powder, measure your dose with the medicine cap on the bottle. This cap should contain dose marks on the inside of it. Pour the powder into 4 to 8 ounces of a cold or hot beverage such as water, juice, soda, coffee, or tea. Stir this mixture and drink it right away. Do not save for later use.
MiraLAX should produce a bowel movement within 1 to 3 days of using the medication. Polyethylene glycol 3350 normally causes loose or even watery stools.
Do not use MiraLAX more than once per day. Call your doctor if you are still constipated or irregular after using this medication for 7 days in a row.
Store at room temperature away from moisture and heat.
Dosing information
Usual Adult Dose of MiraLAX for Constipation:
17 g (diluted in 8 fluid ounces water, juice, soda or coffee) orally once a day
Usual Pediatric Dose for Bowel Preparation:
Occasional constipation:
Children greater than 6 months of age: 0.5 to 1.5 g/kg daily (initial dose 0.5 g/kg; titrate to effect)
Maximum dose: 17 g/dayFecal impaction:
Children greater than 3 years of age: 1 to 1.5 g/kg daily for 3 days
Maximum dose: 100 g dailyBowel preparation:
Children greater than 2 years of age: 1.5 g/kg/day
Maximum dose: 100 g dailyUsual Pediatric Dose of MiraLAX for Constipation — Acute:
Occasional constipation:
Children greater than 6 months of age: 0.5 to 1.5 g/kg daily (initial dose 0.5 g/kg; titrate to effect)
Maximum dose: 17 g/dayFecal impaction:
Children greater than 3 years of age: 1 to 1.5 g/kg daily for 3 days
Maximum dose: 100 g dailyBowel preparation:
Children greater than 2 years of age: 1.5 g/kg/day
Maximum dose: 100 g dailyWhat happens if I miss a dose?
Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.
What happens if I overdose?
Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.
What should I avoid?
Follow your doctor’s instructions about any restrictions on food, beverages, or activity.
MiraLAX side effects
Get emergency medical help if you have any signs of an allergic reaction to MiraLAX: hives; difficult breathing; swelling of your face, lips, tongue, or throat.
Stop taking this medicine and call your doctor at once if you have:
- severe or bloody diarrhea;
- rectal bleeding;
- blood in your stools; or
- severe and worsening stomach pain.
Common MiraLAX side effects may include:
- bloating, gas, upset stomach;
- dizziness; or
- increased sweating.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
What other drugs will affect MiraLAX?
Other drugs may interact with MiraLAX, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell each of your health care providers about all medicines you use now and any medicine you start or stop using.
Popular FAQ
Metamucil and MiraLAX are both brand names for over-the-counter laxatives. This means they help you move feces through your bowels. Metamucil is used to help you have regular bowel movements if you have occasional constipation and you can use it every day. MiraLAX is used to treat occasional constipation. It contains a substance called polyethylene glycol. You should not use it for more than 7 days. Continue reading
For relief of constipation, you can take one dose of MiraLAX at any time of the day for up to 7 days. You may prefer to take it early in the day so that it’s less likely you will have a bowel movement during bedtime or late at night. MiraLAX usually produces a bowel movement in 1 to 3 days. Continue reading
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