Piriton

What is Piriton used for?

Piriton's active ingredient, chlorphenamine, is a first-generation antihistamine that relieves allergy symptoms such as sneezing, runny nose, itchy skin and hives by blocking histamine H1 receptors (with some anticholinergic effect). Because it is a first-generation drug, it is more likely to cause drowsiness, so driving or operating machinery should be avoided after taking it.

How to take Piriton and adjust the dose

Adults and those 12+: typical dose is 4mg every 4-6 hours, maximum 24mg per day. Frail older adults: 4mg every 6-8 hours, maximum 12mg per day. Children 6-11: 2mg every 4-6 hours, maximum 12mg per day. Children 2-5: 1mg every 4-6 hours, maximum 6mg per day, under medical guidance. Infants under 1 year should only use it if prescribed by a doctor. Can be taken with or without food. (Based on NHS and HK retail reference dosing — follow the product label or a pharmacist's advice for the exact dose.)

Piriton side effects

• Common: daytime drowsiness (usually wears off 4-6 hours after a dose), nausea, dizziness or difficulty concentrating, dry mouth, headache, blurred vision
• Serious (rare): yellowing of skin/eyes (possible liver problem), unusual bruising or bleeding, difficulty urinating; signs of anaphylaxis require emergency care immediately

Who should not take Piriton?

• Contraindicated in those allergic to chlorphenamine or other medicines
• Contraindicated if taking (or within 14 days of) a monoamine oxidase inhibitor (MAOI)
• Contraindicated in primary angle-closure glaucoma
• Use with caution in epilepsy or seizure risk
• Use with caution in urinary retention or enlarged prostate
• Children under 6 should not take combination cold medicines containing chlorphenamine