These drugs are meant to relieve the symptoms of colds and flu, such as coughing, nasal congestion, aches, and fever. Many of these medications are available in both drowsy and non-drowsy forms. People using any medications that cause drowsiness should avoid driving or any other activity that requires alertness. These medications are most often used by people who have allergies. When a person is allergic to something, their body produces histamines, causing a number of unpleasant physical reactions including puffy eyes, nasal congestion, and sneezing.
Antihistamines block the body's histamine reaction and lessen or prevent allergic reactions.
Anyone who is allergic to antihistamines should not take them. If you are taking other drugs, check with your doctor or pharmacist before taking an antihistamine. Some drugs increase the drowsiness effect of antihistamines while other drugs reduce the histamine-blocking effect. Antacids People use antacids to relieve pain from heartburn or an ulcer. Antacids work by neutralizing the excess stomach acid that causes pain.