Antihistamine (Oral Route, Parenteral Route, Rectal Route)Drug Information provided by: Micromedex
US Brand Names
Canadian Brand Names
Antihistamines are used to relieve or prevent the symptoms of hay fever and other types of allergy. They work by preventing the effects of a substance called histamine, which is produced by the body. Histamine can cause itching, sneezing, runny nose, and watery eyes. Also, in some persons histamine can close up the bronchial tubes (air passages of the lungs) and make breathing difficult.
Some of the antihistamines are also used to prevent motion sickness, nausea, vomiting, and dizziness. In patients with Parkinson's disease, diphenhydramine may be used to decrease stiffness and tremors. Also, the syrup form of diphenhydramine is used to relieve the cough due to colds or hay fever. In addition, since antihistamines may cause drowsiness as a side effect, some of them may be used to help people go to sleep.
Hydroxyzine is used in the treatment of nervous and emotional conditions to help control anxiety. It can also be used to help control anxiety and produce sleep before surgery.
Some antihistamines are used in the treatment of chronic urticaria, which is a persistent hive-like rash.
Antihistamines may also be used for other conditions as determined by your doctor.
Antihistamine preparations are available both over-the-counter (OTC) and with your doctor's prescription.
Do not give any over-the-counter (OTC) cough and cold medicine to a baby or child under 4 years of age. Using these medicines in very young children might cause serious or possibly life-threatening side effects .
Once a medicine has been approved for marketing for a certain use, experience may show that it is also useful for other medical problems. Although these uses are not included in product labeling, some antihistamines are used in certain patients with the following medical conditions:
- Appetite stimulant in children and adults (cyproheptadine)
- Asthma together with asthma medicines before and during exposure to substances that cause reactions, to prevent or reduce bronchospasm (wheezing or difficulty in breathing) (cetirizine and loratadine)
- Vascular headache treatment (cyproheptadine)
Make certain your health care professional knows if you are on a low-sodium, low-sugar, or any other special diet. Most medicines contain more than their active ingredient, and many liquid medicines contain alcohol.
This product is available in the following dosage forms:
- Tablet, Extended Release
- Tablet, Chewable
- Powder for Suspension
- Tablet, Disintegrating
- Capsule, Liquid Filled
- Capsule, Extended Release
- Suspension, Extended Release