Antihistamines Antihistamines are widely used in both the human and animal medical fields. Most of the antihistamines used in veterinary medicine are antihistamines that were designed for and used primarily by humans. When used as part of a treatment plan including fatty acids and avoidance, the percent of respondents goes much higher. Every animal will respond differently to each of the different antihistamines. Therefore several different antihistamines may have to be used before an effective one is found.
Every antihistamine has a different dose and risk of side effects.
Antihistamines should be used with veterinary guidance. Some common side effects include sedation, hyperactivity, constipation, dry mouth and inappetence. The correct antihistamine given at the proper dose should not cause unwanted side effects. For severely itchy dogs mild sedation may be a positive and desired side effect. Antihistamines come in several forms including H1 and H2 blockers.