Acetaminophen is sold under many brand names, including Tylenol. It’s found in the following Nyquil products:
Dextromethorphan Side Effects
Medically reviewed by Drugs.com. Last updated on Feb 8, 2023.
Applies to dextromethorphan: oral capsule liquid filled, oral elixir, oral liquid, oral solution, oral suspension extended release, oral syrup, oral tablet.
Serious side effects of Dextromethorphan
Along with its needed effects, dextromethorphan may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor as soon as possible if any of the following side effects occur while taking dextromethorphan:
Symptoms of overdose
- Blurred vision
- confusion
- difficulty in urination
- drowsiness or dizziness
- nausea or vomiting (severe)
- shakiness and unsteady walk
- slowed breathing
- unusual excitement, nervousness, restlessness, or irritability (severe)
Other side effects of Dextromethorphan
Some side effects of dextromethorphan may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.
Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
Less common or rare
- Confusion
- constipation
- dizziness (mild)
- drowsiness (mild)
- headache
- nausea or vomiting
- stomach pain
For Healthcare Professionals
Applies to dextromethorphan: compounding powder, oral capsule, oral disintegrating strip, oral drops, oral liquid, oral lozenge, oral solution, oral suspension extended release, oral syrup, oral tablet chewable.
General
Adverse effects have included gastrointestinal disturbances such as stomach upset and diarrhea. [Ref]
Nervous system
Frequency not reported: Drowsiness, dizziness, convulsions [Ref]
Respiratory
Frequency not reported: Respiratory depression [Ref]
Gastrointestinal
Frequency not reported: Vomiting, nausea, diarrhea, abdominal pain, gastrointestinal disturbance [Ref]
Hypersensitivity
Rare (less than 0.1%): Fixed-drug eruptions [Ref]
Psychiatric
Cases of abuse have been reported. [Ref]
Frequency not reported: Mental confusion, excitation, insomnia, abuse [Ref]
Dermatologic
Frequently asked questions
More about dextromethorphan
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Patient resources
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- Dextromethorphan (Advanced Reading)
- Dextromethorphan Chewable Tablets
- Dextromethorphan Capsules
- Dextromethorphan Extended-Release Suspension
Other brands
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References
1. Cerner Multum, Inc. “UK Summary of Product Characteristics.” O 0
2. Hall RC, Beresford TP, Stickney SK, Nasdahl CS, Coleman JH “Psychiatric reactions produced by respiratory drugs.” Psychosomatics 26 (1985): 605-8,616-7
3. Helfer J, Kim OM “Psychoactive abuse potential of Robitussin-DM.” Am J Psychiatry 147 (1990): 672-3
4. Murray S, Brewerton T “Abuse of over-the-counter dextromethorphan by teenagers.” South Med J 86 (1993): 1151-3
5. Wolfe TR, Caravati EM “Massive dextromethorphan ingestion and abuse.” Am J Emerg Med 13 (1995): 174-6
6. Polles A, Griffith JL “Dextromethorphan-induced mania.” Psychosomatics 37 (1996): 71-4
7. Bostwick JM “Dextromethorphan-induced manic symptoms in a bipolar patient on lithium.” Psychosomatics 37 (1996): 571-2
8. Stubb S, Reitamo S “Fixed-drug eruption due to dextromethorphan .” Arch Dermatol 126 (1990): 970-1
9. Knowles SR, Weber E “Dextromethorphan anaphylaxis.” J Allerg Clin Immunol 102 (1998): 316-7
Further information
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.
Some side effects may not be reported. You may report them to the FDA.
Can Nyquil Make You Sleepy?
Nyquil is a common over-the-counter medication. It’s formulated to treat nighttime cold and flu symptoms.
In addition to helping alleviate a fever, stuffy nose, and cough, Nyquil can also cause drowsiness. As a result, it may help with sleep.
In this article, we’ll look at the Nyquil ingredients that can cause sleepiness, as well as the other potential side effects of this medication and the safety concerns regarding its use as a sleep aid.
There are many Nyquil products to choose from, most of which can cause sleepiness. In general, you’ll start to feel drowsy within a half an hour of taking Nyquil.
Nyquil products may contain several or all of the active ingredients listed below at varying doses. Nyquil Severe products tend to contain additional ingredients.
Acetaminophen
Acetaminophen is a common pain reliever. It targets symptoms such as minor aches and pains, fever, headache, and sore throat. It carries a low risk of side effects when taken at the recommended dosage.
However, higher doses of acetaminophen can be dangerous. If you take more acetaminophen than is safe for you, it can cause liver damage. The recommended maximum daily dose of acetaminophen is 3,000 milligrams (mg). But the difference between a safe dose and a dose that could harm your liver is very small.
Acetaminophen is sold under many brand names, including Tylenol. It’s found in the following Nyquil products:
- Nyquil Cold and Flu Nighttime Relief (Liquid and LiquiCaps)
- Nyquil Severe Cough, Cold, and Flu Nighttime Relief (Liquids, LiquiCaps, and VapoCool Caplets)
- Nyquil High Blood Pressure Cold and Flu Medicine
Dextromethorphan HBr
Dextromethorphan is a cough suppressant. It works by reducing brain signals that trigger coughing.
Although side effects are typically mild, they can include:
- drowsiness
- lightheadedness
- restlessness
- gastrointestinal symptoms
Dextromethorphan HBr is found in the following Nyquil products:
- Nyquil Cold and Flu Nighttime Relief (Liquid and LiquiCaps)
- Nyquil Severe Cough, Cold, and Flu Nighttime Relief (Liquids, LiquiCaps, and VapoCool Caplets)
- Nyquil Cough DM and Congestion Medicine (Liquid)
- Nyquil High Blood Pressure Cold and Flu Medicine (Liquid)
Doxylamine succinate
Doxylamine succinate is an antihistamine. Antihistamines work by blocking the action of histamine, a substance associated with allergy symptoms.
By targeting histamine, doxylamine succinate helps relieve sneezing, runny nose, and sinus congestion. It causes significant drowsiness, as well as headaches and sinus dryness.
Doxylamine succinate is found in the following Nyquil products:
- Nyquil Cold and Flu Nighttime Relief (Liquid and LiquiCaps)
- Nyquil Severe Cough, Cold, and Flu Nighttime Relief (Liquids, LiquiCaps, and VapoCool Caplets)
- Nyquil Cough DM and Congestion Medicine (Liquid)
- Nyquil High Blood Pressure Cold and Flu Medicine (Liquid)
Phenylephrine HCl
Phenylephrine HCl is a decongestant. It relieves symptoms associated with sinus congestion, such as a runny nose. It doesn’t cause sleepiness. Other side effects include dizziness, headache, and upset stomach.
Phenylephrine HCl is found in the following Nyquil products:
- Nyquil Severe Cough, Cold, and Flu Nighttime Relief (Liquids, LiquiCaps, and VapoCool Caplets)
- Nyquil Cough DM and Congestion Medicine
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