Chlorpheniramine

CHLOR-TRIMETON

What it isFirst-generation H1 antagonist; allergic rhinitis and cold remedies.

Why this oneIt is less sedating than diphenhydramine but remains common in multi-ingredient cold products.

What limits itAnticholinergic burden and sedation make it poor for older adults and unsafe before driving.

FDA-approved for

FDA dosing	Population	Start	Target	Max
Temporary relief of hay fever/upper respiratory allergy symptoms (sneezing, runny nose, itchy watery eyes, itchy nose/throat)	Adults & children ≥12 y	1 tablet (4 mg) q4–6h PRN	1 tablet (4 mg) q4–6h PRN	6 tablets (24 mg)/24 h
Temporary relief of hay fever/upper respiratory allergy symptoms	Children 6 to <12 y	1/2 tablet (2 mg) q4–6h PRN (break tablet in half)	1/2 tablet (2 mg) q4–6h PRN	3 whole tablets (12 mg)/24 h

Renal Undefined

Hepatic Undefined

Dose no more often than every 4 to 6 hours; do not exceed the stated 24-hour tablet limit.

Ask a doctor before use if you have glaucoma, a breathing problem (emphysema, chronic bronchitis), or difficulty urinating due to enlarged prostate.
Drowsiness may occur — use caution when driving or operating machinery.
Excitability may occur, especially in children.
Avoid alcohol; alcohol, sedatives, and tranquilizers may increase drowsiness — ask a doctor/pharmacist before use if taking sedatives or tranquilizers.
Do not use to make a child sleepy; do not use in children under 6 years.

Pregnancy If pregnant, ask a health professional before use (OTC drug-facts statement).

Lactation If breast-feeding, ask a health professional before use (OTC drug-facts statement).

NO BOXED WARNINGS

Principal riskAnticholinergic burden and sedation, so it is poor in the elderly

Direct muscarinic antagonism1 / 4