The following interventions may be used to treat an allergic reaction to a drug: Withdrawal of the drug. If your doctor determines that you have a drug allergy — or likely allergy — discontinuing the drug is the first step in treatment. In many cases, this may be the only intervention necessary. Antihistamines. Your doctor may prescribe an antihistamine or recommend an over-the-counter antihistamine such as diphenhydramine that can block immune system chemicals activated during an allergic reaction. Corticosteroids. Either oral or injected corticosteroids may be used to treat inflammation associated with more-serious reactions...zinetac is antihistaminic...continue same and be in regular fallow up with your doctor they will do the needful.