Syn-Rx DM Side Effects
Generic name: dextromethorphan / guaifenesin / pseudoephedrine
Medically reviewed by Drugs.com. Last updated on Jun 19, 2022.
Note: This document contains side effect information about dextromethorphan / guaifenesin / pseudoephedrine. Some of the dosage forms listed on this page may not apply to the brand name Syn-Rx DM.
For the Consumer
Applies to dextromethorphan / guaifenesin / pseudoephedrine: oral capsule, oral liquid, oral tablet, oral tablet extended release
Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.
Stop using this medication and call your doctor at once if you have:
fast or uneven heart rate;
dangerously high blood pressure (severe headache, blurred vision, buzzing in your ears, anxiety, chest pain, uneven heartbeats, seizure).
Common side effects may include:
sleep problems (insomnia); or
feeling nervous, restless, or irritable.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects.
For Healthcare Professionals
The manufacturer has not provided adverse event information.[Ref]
More about Syn-Rx DM (dextromethorphan / guaifenesin / pseudoephedrine)
Related treatment guides
1. "Product Information. Pecgen PSE (dextromethorphan / guaifenesin / pseudoephedrine)." KramerNovis (2019):
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.