G-Phen DM Side Effects
Generic name: dextromethorphan / guaifenesin / phenylephrine
Medically reviewed by Drugs.com. Last updated on Jan 24, 2022.
Note: This document contains side effect information about dextromethorphan / guaifenesin / phenylephrine. Some of the dosage forms listed on this page may not apply to the brand name G-Phen DM.
For the Consumer
Applies to dextromethorphan / guaifenesin / phenylephrine: oral liquid, oral suspension, oral syrup, 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 medicine and call your doctor at once if you have:
little or no urination;
fast or slow heartbeats;
confusion, dizziness, feeling unsteady;
severe headache, blurred vision, pounding in your neck or ears;
slow breathing; or
unusual changes in mood or behavior.
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 G-Phen DM (dextromethorphan / guaifenesin / phenylephrine)
Related treatment guides
1. "Product Information. Presgen B (brompheniramine/dextromethorph/phenylephrine)." KramerNovis (2019):
Some side effects may not be reported. You may report them to the FDA.