Mytussin AC Side Effects
Generic Name: codeine / guaifenesin
Note: This document contains side effect information about codeine / guaifenesin. Some of the dosage forms listed on this page may not apply to the brand name Mytussin AC.
For the Consumer
Applies to codeine / guaifenesin: oral liquid, oral solution, oral syrup
What are some side effects that I need to call my doctor about right away?
WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:
- Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing, swallowing, or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.
- Very bad dizziness or passing out.
- Chest pain or pressure or a fast heartbeat.
- Trouble breathing, slow breathing, or shallow breathing.
- Noisy breathing.
- Feeling very sleepy.
- Feeling confused.
- A heartbeat that does not feel normal.
- Hallucinations (seeing or hearing things that are not there).
- Mood changes.
- Very bad belly pain.
- Very bad headache.
- Trouble passing urine.
- Change in eyesight.
- Very upset stomach or throwing up.
- Very bad constipation.
- Feeling very tired or weak.
What are some other side effects of this drug?
All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if any of these side effects or any other side effects bother you or do not go away:
- Feeling sleepy.
- Upset stomach or throwing up.
- Sweating a lot.
- Feeling tired or weak.
These are not all of the side effects that may occur. If you have questions about side effects, call your doctor. Call your doctor for medical advice about side effects.
You may report side effects to the FDA at 1-800-FDA-1088. You may also report side effects at http://www.fda.gov/medwatch.
For Healthcare Professionals
Frequency not reported: Nausea, vomiting, constipation, biliary tract spasm, increased colonic motility, toxic dilation
Codeine-induced rash may be related to direct stimulation of histamine release.[Ref]
Frequency not reported: Rash
Frequency not reported: Rash[Ref]
Frequency not reported: Hypersensitivity reactions (pruritus, urticaria)
Frequency not reported: Visual disturbances
Frequency not reported: Euphoria, dysphoria, transient hallucination, disorientation
Respiratory depression and death have occurred in children who received codeine in the postoperative period following tonsillectomy and/or adenoidectomy. Further investigation has shown these patients to be ultra-rapid metabolizers of codeine. Children with obstructive sleep apnea who are treated with codeine appear to be particularly sensitive to the respiratory depressant effects of codeine.[Ref]
1. de Groot AC, Conemans J "Allergic urticarial rash from oral codeine." Contact Dermatitis 14 (1986): 209-14
2. "Product Information. Robitussin (guaifenesin)." Wyeth-Ayerst Laboratories, Philadelphia, PA.
3. Gonzalogarijo MA, Revengaarranz F "Fixed drug eruption due to codeine." Br J Dermatol 135 (1996): 498-9
4. US Food and Drug Administration "FDA News Release: FDA requires strong warnings for opioid analgesics, prescription opioid cough products, and benzodiazepine labeling related to serious risks and death from combined use. Available from: URL: http://www.fda.gov/NewsEvents/Newsroom/PressAn" ([2016, Aug 31]):
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.
More about Mytussin AC (codeine / guaifenesin)
- During Pregnancy
- Dosage Information
- Drug Interactions
- En Español
- Drug class: upper respiratory combinations
- FDA Alerts (6)