General and Systematic Veterinary Pharmacology

ANTIHISTAMINICS

• The role of histamine in the eitology of bronchoconstriction during hypersensitivity reactions has given histamine antagonists (H1) antagonists an important place in the management of airway disease.
• The antihistaminics possess parasympatholytic, local anesthetic and CNS sedative action, all of which may be beneficial in cough control.
• Antihistaminics  such as diphenhydramine are incorporated in compound cough remedies.
• These drugs have the advantage over the corticosteroids that they may be given continuously without ill effect.
• The mild antitussive effect is accompanied by a not always helpful reduction in secretions and inhibition of mucus transport.