Antihistamines

Recommended dosage depends on the type of antihistamine. Check with the physician who prescribed the drug or the pharmacist who filled the prescription for the correct dosage, and always take antihistamines exactly as directed. If using non-prescription (over-the-counter) types, follow the directions on the package label. Never take larger or more frequent doses, and do not take the drug longer than directed.

For best effects, take antihistamines on a schedule, not just as needed. Histamine is released more or less continuously, so countering its effects requires regular use of antihistamines.