CyproheptadineDose, contraindications and adverse effects for Cats, Dogs and Horses.

First-generation H1 antihistamine with serotonin-antagonist activity; used for allergic disease and as an appetite stimulant in cats. Cyproheptadine may be useful in cats as an appetite stimulant,1,2 but it is not recommended in the management of hepatic lipidosis. It may be useful for urine spraying in male cats. Cyproheptadine use in cats as monotherapy for eosinophilic airway inflammation and asthma is not effective. Cyproheptadine is indicated for the treatment of histamine-mediated pruritic and allergic skin conditi

Similar to other H1-receptor antihistamines, cyproheptadine acts by competing with histamine for H1-receptor sites on effector cells. An- tihistamines do not block histamine release but can antagonize its effects. Cyproheptadine also possesses potent antiserotonin activity, in addition to anticholinergic and calcium channel blocking actions.

Cyproheptadine is contraindicated in patients hypersensitive to it. In humans, the manufacturer states the drug is contraindicated in newborn or premature infants, and should be used with caution in patients with prostatic hypertrophy, hyperthyroidism, bladder neck obstruction, severe cardiac disease, hypertension, epilepsy, angle-closure glaucoma or increased intraocular pressure, or pyloroduodenal obstruction.

The most likely adverse effects seen with cyproheptadine use in veterinary patients are related to its CNS depressant (eg, sedation) and anticholinergic effects (eg, dry mucous membranes, decreased GI motility, hyperthermia, tachycardia, urine retention). Polyphagia may be an unwanted effect in dogs8 and cats20 when this drug is used for indications other than as an appetite stimulant.

■ Appetite ■ Body weight ■ Adverse effects (eg, CNS depression, anticholinergic effects [eg, dry mucous membranes, tachycardia, urine retention])