Return to top Benadryl is an antihistamine with drying and sedative effects. It relieves red, inflamed eyes caused by food allergies and the itching, swelling, and redness from hives and other rashes that are caused by mild allergic reactions. Antihistamines work by decreasing the effects of histamine, a chemical released in the body that narrows air passages in the lungs and contributes to inflammation.
Antihistamines reduce itching and swelling and dry up secretions from the nose, eyes, and throat.
Most important fact about this drug Return to top Antihistamines may produce excitability in children. In the elderly they may cause dizziness, excessive calm, or low blood pressure. Return to top Benadryl should be taken exactly as prescribed, or follow instructions on the label. Take it as soon as you remember. If it is almost time for your next dose, skip the one you missed and go back to your regular schedule.