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P-Tann Side Effects

Generic name: chlorpheniramine

Medically reviewed by Last updated on Jan 26, 2024.

Note: This document contains side effect information about chlorpheniramine. Some dosage forms listed on this page may not apply to the brand name P-Tann.

Applies to chlorpheniramine: oral syrup, oral tablet, oral tablet extended release.

Serious side effects of P-Tann

WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:

Other side effects of P-Tann

All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if any of these side effects or any other side effects bother you or do not go away:

These are not all of the side effects that may occur. If you have questions about side effects, call your doctor. Call your doctor for medical advice about side effects.

You may report side effects to the FDA at 1-800-332-1088. You may also report side effects at

For Healthcare Professionals

Applies to chlorpheniramine: compounding powder, injectable solution, oral capsule extended release, oral liquid, oral suspension extended release, oral syrup, oral tablet, oral tablet chewable, oral tablet extended release.

Nervous system

Very common (10% or more): Sedation, somnolence

Common (1% to 10%): Disturbance in attention, abnormal coordination, dizziness, headache[Ref]

Nearly all patients treated with chlorpheniramine experience drowsiness. This drowsiness may subside in some patients with extended use.

Few cases of dyskinesias and tremors, often of the face, have been reported in patients whose chronic use of chlorpheniramine extended over a period of 3 to 10 years. Some of these cases were only partially relieved by discontinuation of the drug. Haloperidol was successful in relieving symptoms.[Ref]


Frequency not reported: Palpitations, tachycardia, arrhythmias, hypotension[Ref]


Common (1% to 10%): Blurred vision[Ref]


Common (1% to 10%): Nausea, dry mouth

Frequency not reported: Vomiting, abdominal pain, diarrhea, dyspepsia[Ref]


Frequency not reported: Allergic reaction, angioedema, anaphylactic reactions[Ref]


Frequency not reported: Exfoliative dermatitis, rash, urticaria, photosensitivity[Ref]


Common (1% to 10%): Fatigue

Frequency not reported: Tinnitus, chest tightness[Ref]


Frequency not reported: Confusion, excitation, irritability, nightmares, depression[Ref]


Frequency not reported: Hemolytic anemia, blood dyscrasias[Ref]

A fatal case of agranulocytosis has been reported in a patient taking chlorpheniramine, pseudoephedrine, acetaminophen, dextromethorphan, phenylpropanolamine, and aspirin. Chlorpheniramine was felt to be the cause.[Ref]


Frequency not reported: Urinary retention[Ref]


Frequency not reported: Muscle twitching, muscle weakness[Ref]


Frequency not reported: Hepatitis, jaundice[Ref]


Frequency not reported: Thickening of bronchial secretions[Ref]


Frequency not reported: Anorexia[Ref]

Frequently asked questions


1. Cerner Multum, Inc. "UK Summary of Product Characteristics."

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.