Harvard Health Letter

Understanding allergy medications

Treating allergies usually starts with over-the-counter products. If they’re not helpful, prescription medications and nasal sprays may do the job. Antihistamines block the production and efficiency of histamine, which is released during an allergic reaction. Decongestants can help shrink blood vessels in the nasal passages, but may cause problems in the long term or when used in combination with antihistamines. Steroid sprays reduce swelling and nasal congestion and are available in a prescription spray form. Nonsteroid nasal sprays are available over the counter and can be effective, but must be used several times a day.
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