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Allerx-D Side Effects

Generic Name: methscopolamine / pseudoephedrine

Note: This page contains information about the side effects of methscopolamine / pseudoephedrine. Some of the dosage forms included on this document may not apply to the brand name Allerx-D.

For the Consumer

Applies to methscopolamine / pseudoephedrine: extended-release tablets

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

Constipation; diarrhea; dizziness; drowsiness; dry mouth, nose, or throat; excitability; headache; loss of appetite; nausea; nervousness or anxiety; restlessness; trouble sleeping; upset stomach; vomiting; weakness.

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

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); difficulty urinating or inability to urinate; fast or irregular heartbeat; hallucinations; mental or mood changes; seizures; severe dizziness, lightheadedness, or headache; tremor; vision changes.

For Healthcare Professionals

Applies to methscopolamine / pseudoephedrine: oral tablet extended release


Cardiovascular side effects have included cardiac palpitations. In general, sympathomimetics have been associated with tachycardia, arrhythmias, and cardiovascular collapse with hypotension.[Ref]

Nervous system

Nervous system side effects have included drowsiness, lassitude, increased irritability and excitement (especially in children). Other side effects associated with sympathomimetic amines have included headache, dizziness, anxiety, fear, nervousness, restlessness, tremor, weakness, insomnia, hallucinations, convulsions, and CNS depression.

Antihistamines and anticholinergic drugs side effects have included drowsiness and dizziness.[Ref]


Gastrointestinal side effects have included nausea and excessive dryness of the mouth, nose and throat.[Ref]


Ocular side effects have included blurred vision.[Ref]


Genitourinary side effects associated with the used of sympathomimetic amines have included dysuria and urinary retention in patients with prostatic hypertrophy.[Ref]


Respiratory side effects associated with the use of sympathomimetics have included respiratory difficulty.[Ref]


1. "Product Information. PSE 120/MSC 2.5 (methscopolamine-pseudoephedrine)." Cypress Pharmaceutical Inc, Madison, MS.

Not all side effects for Allerx-D 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.