What is allergy medicines?

Decongestants and some antihistamines may not be safe for young children, older adults, or people who have certain health problems. Before you use them, check the label. If you do use these medicines, always follow the directions about how much to use based on age and, in some cases, weight.

Side effects depend on the type of medicine.

• Corticosteroid sprays can dry or irritate the nose. They can cause coughing, sneezing, diarrhea, or nausea.
• Antihistamines such as cetirizine (Zyrtec) and loratadine (Claritin) cause few side effects. Antihistamines like diphenhydramine (Benadryl) and chlorpheniramine (Chlor-Trimeton) may have more side effects. For example, they may make you tired or cause dry eyes or a dry mouth. They can also cause heart, bowel, or bladder problems.
• Decongestants can cause a dry or irritated nose, sneezing, or a stinging or burning feeling in the nose. They may also cause a rapid heartbeat, blurred vision, or dizziness. Side effects can also include sleep problems or feeling anxious or over-excited.