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Dextromethorphan / guaifenesin / pseudoephedrine Side Effects

For the Consumer

Applies to dextromethorphan / guaifenesin / pseudoephedrine: tablets

Check with your doctor if any of these most COMMON side effects persist or become bothersome:

Diarrhea; dizziness; drowsiness; excitability; headache; irritability; nausea; stomach upset; trouble sleeping.

Seek medical attention right away if any of these SEVERE side effects occur while taking dextromethorphan / guaifenesin / pseudoephedrine:

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); difficulty urinating; fast, slow, or irregular heartbeat; fever; hallucinations; mental or mood changes (eg, anxiety, nervousness); paleness; seizures; severe or persistent dizziness, lightheadedness, or headache; tremor.

For Healthcare Professionals

Applies to dextromethorphan / guaifenesin / pseudoephedrine: oral capsule, oral liquid, oral suspension, oral suspension extended release, oral syrup, oral tablet, oral tablet extended release


Frequency not reported: Rash[Ref]

Nervous system

Frequency not reported: Nervousness, dizziness, insomnia, headache[Ref]


Frequency not reported: Fever[Ref]


Frequency not reported: Cough, nasal congestion[Ref]


1. "Product Information. Tusnel (dextromethorphan/guaiFENesin/pseudoephedrine)." Llorens Pharmaceuticals, Miami, FL.

2. "Product Information. ExeFen-DMX (dextromethorphan/guaiFENesin/pseudoephedrine)." Larken Laboratories Inc, Madison, MS.

3. "Product Information. Capmist DM (dextromethorphan/guaiFENesin/pseudoephedrine)." Capital Pharmaceutical, Powell, OH.

4. "Product Information. Tusnel Pediatric Drops (guaiFENesin-pseudoephedrine)." Llorens Pharmaceuticals, Miami, FL.

5. "Product Information. Z-Cof 12DM (dextromethorphan / guaifenesin / pseudoephedrine)." Zyber Pharmaceuticals Inc, Gonzales, LA.

Not all side effects for dextromethorphan / guaifenesin / pseudoephedrine may be reported. You should always consult a doctor or healthcare professional for medical advice. Side effects can be reported to the FDA here.

Disclaimer: Every effort has been made to ensure that the information provided is accurate, up-to-date and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This material does not endorse drugs, diagnose patients, or recommend therapy. This information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill , knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate safety, effectiveness, or appropriateness for any given patient. does not assume any responsibility for any aspect of healthcare administered with the aid of materials provided. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the substances you are taking, check with your doctor, nurse, or pharmacist.