treats heart rhythm problems, stomach or bowel problems, and certain types of poisoning. Also used before surgery to decrease saliva. Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing, Fast heartbeat., Lightheadedness or fainting., Seizures., Trouble swallowing. Antihistamine, It can treat pain and itching caused by insect bites, minor cuts, burns, poison ivy, poison oak, and poison sumac when applied topically. In its oral form, it can treat hay fever, allergies, cold symptoms, and insomnia. In its injected form, it can treat severe allergic reactions, motion sickness, and symptoms of Parkinson's disease.