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How long do antihistamines last?

Modern non-drowsy antihistamines, such as cetirizine, loratadine, and fexofenadine, typically last around 24 hours and are taken once a day. Older sedating types, like chlorphenamine and diphenhydramine, usually last 4 to 6 hours and may need more frequent doses. Always check the packet for exact dosing instructions, as effects can vary between people.

Key points:

• Non-drowsy antihistamines provide relief for about 24 hours.
• Sedating antihistamines last around 4 to 6 hours.
• Duration depends on the type of antihistamine taken.
• Tablets treat symptoms body-wide, while sprays or drops act faster but only locally.

This text has been fact-checked for accuracy by medino's clinical team.