4mg every four to six hours up to a maximum of 24mg daily or as prescribed by a physician.
Chlorphenamine Tab 4mg (HISTAPEN)-100
Indications: Used for the symptomatic relief of allergic conditions including urticaria and angioedema, rhinitis, and conjunctivitis, and in pruritic skin disorders.

4mg every four to six hours up to a maximum of 24mg daily or as prescribed by a physician.
The most common side effect of the sedating antihistamines is CNS depression, with effects varying from slight drowsiness to deep sleep, and including lassitude, dizziness, and incoordination.
Recommended Drug - Allergies - Allergic Rhinitis Medicines
The most common side effect of the sedating antihistamines is CNS depression, with effects varying from slight drowsiness to deep sleep, and including lassitude, dizziness, and incoordination.