Assess allergy history, age restrictions, and concurrent medications before recommending chlorpheniramine-containing products.
Absolute: hypersensitivity to chlorpheniramine, concurrent MAOIs, narrow-angle glaucoma, urinary retention, and use in infants <2 years. Relative: hepatic impairment, asthma/COPD, cardiovascular disease, seizure disorders, and concurrent CNS depressants.
Children under 2 years (risk of fatal respiratory depression)
Known hypersensitivity to chlorpheniramine or formulation excipients
Use of monoamine oxidase inhibitors within the past 14 days
Narrow-angle glaucoma
Bladder neck obstruction or urinary retention
Children 2–5 years—off-label use requires clinician oversight and careful dosing
Chronic lung disease with thick secretions (e.g., cystic fibrosis, bronchiectasis)
Cardiovascular disease or uncontrolled hypertension
Hyperthyroidism
Concurrent sedating medications, alcohol, or other anticholinergics
Seizure disorders or sleep apnea—monitor for CNS depression
Avoid in breastfeeding due to potential infant sedation. Use in pregnancy only if benefits outweigh risks.