Skip to main content

Chlorpheniramine / dextromethorphan / methscopolamine Side Effects

Applies to chlorpheniramine/dextromethorphan/methscopolamine: oral tablet extended release.


Do not use this medicine if you have taken an MAO inhibitor in the past 14 days. A dangerous drug interaction could occur. MAO inhibitors include isocarboxazid, linezolid, phenelzine, rasagiline, selegiline, and tranylcypromine.

Get emergency medical help if you have any of these signs of an allergic reaction while taking chlorpheniramine/dextromethorphan/methscopolamine: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Stop using this medicine and call your doctor at once if you have:

Common side effects may include:

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

Applies to chlorpheniramine / dextromethorphan / methscopolamine: oral tablet extended release.


Cardiovascular side effects have included bradycardia, tachycardia, flushing, and, palpitations.[Ref]


Gastrointestinal side effects have included nausea, xerostomia, diarrhea, abdominal pain, appetite increase, weight gain, constipation, and dysphagia.[Ref]


Ocular side effects have included mydriasis, diplopia, and blurred vision.[Ref]


Musculoskeletal side effects have included arthralgia and weakness.[Ref]

Nervous system

Nervous system side effects have included headache, excitability, irritability, fatigue, nervousness, dizziness, drowsiness, confusion, and memory impairment.[Ref]


Genitourinary side effects have included urinary retention.[Ref]


Renal side effects have included polyuria.[Ref]


Respiratory side effects have included pharyngitis.[Ref]

More about chlorpheniramine / dextromethorphan / methscopolamine

Related treatment guides


1. (2022) "Product Information. Extendryl DM (chlorpheniramine/DM/methscopolamine)." Apothecon Inc

Further information

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.