Dextromethorphan-Guaifenesin Side Effects

Possible side effects of dextromethorphan and guaifenesin are listed below. Call your doctor for medical advice if they are severe or last more than a few days.

• Dizziness
• Drowsiness
• Headache
• Restlessness
• Nervousness
• Stomach pain
• Nausea
• Vomiting 

Dextromethorphan and guaifenesin can also cause more serious unwanted or dangerous effects. Call your doctor right away or seek emergency medical help if you develop the following serious symptoms:

Skin rash, hives, itching, peeling, or blistering skin (allergic reaction)

The above list may not include all the potential side effects of dextromethorphan and guaifenesin. Contact your healthcare provider if your side effects are unusual or severe or they do not get better over time. You can also report unusual side effects to the Food and Drug Administration at 1-800-FDA-1088.

Dextromethorphan and guaifenesin Overdose: In case of an overdose of dextromethorphan and guaifenesin, call your doctor immediately. You can also call your local poison control center, provincial poison control center, or the national poison control center at 1-800-222-1222. If someone has trouble breathing, is unresponsive, has had a seizure, or has collapsed, call 911. Overdose symptoms may include dizziness, drowsiness, unsteadiness, nausea, vomiting, fast heartbeat, difficulty breathing, vision changes, hallucinations, seizures, and coma.

Source: FDA