Chlorpheniramine Side Effects
Some side effects of chlorpheniramine may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.
For the Consumer
Applies to chlorpheniramine: capsules, controlled-release capsules, suspension drops, sustained-release capsules, syrup, tablets
Other dosage forms:
Check with your doctor if any of these most COMMON side effects persist or become bothersome:
Seek medical attention right away if any of these SEVERE side effects occur while taking chlorpheniramine:
Constipation; diarrhea; dizziness; drowsiness; dry mouth, nose, or throat; excitability; headache; loss of appetite; nausea; nervousness or anxiety; trouble sleeping; upset stomach; vomiting; weakness.
Severe allergic reactions (rash; hives; 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; seizures; severe dizziness, lightheadedness, or headache; tremor; trouble sleeping; vision changes.
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
Central nervous system side effects have included depression resulting in drowsiness in 75% or more of treated patients. Dyskinesias have rarely been reported following chronic use of chlorpheniramine.
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.
Gastrointestinal side effects have included dry mouth and constipation in up to one-third of treated patients.
Cardiovascular side effects have included hypotension, tachycardia, and palpitations.
Ocular side effects of chlorpheniramine may include blurred vision, diplopia, and dry eyes due to anticholinergic effects.
Genitourinary side effects have included dysuria, urinary hesitancy, and a decreased urine flow. In rare cases, the anticholinergic effect of chlorpheniramine has precipitated acute urinary retention.
Hematologic side effects have included bone marrow suppression, thrombocytopenia, and aplastic anemia.
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.
More about chlorpheniramine
- Chlorpheniramine controlled-release capsules
- Chlorpheniramine suspension
- Chlorpheniramine suspension drops
- Chlorpheniramine sustained-release capsules
- Chlorpheniramine syrup
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