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Chlorpheniramine / dextromethorphan / methscopolamine Side Effects

For the Consumer

Applies to chlorpheniramine / dextromethorphan / methscopolamine: tablets

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

Blurred vision; change in appetite; constipation; dizziness; drowsiness; dry mouth, nose, or throat; excitability (especially in children); headache; lightheadedness; nausea; nervousness; restlessness; stomach upset or pain; tiredness; trouble sleeping; vomiting.

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

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); confusion; difficulty swallowing; difficulty urinating; fast, slow, or irregular heartbeat; flushing; hallucinations; increased irritability or excitability; memory problems; seizures; severe clumsiness; severe dizziness, drowsiness, headache, or lightheadedness; sore throat; unusual tiredness or weakness; vision changes.

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]


1. "Product Information. Extendryl DM (chlorpheniramine/DM/methscopolamine)." Aura Laboratories, Fort Lauderdale, FL.

Not all side effects for chlorpheniramine / dextromethorphan / methscopolamine 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.