Pharmacotherapeutic group: Adrenergics for systemic use (selective beta2-adrenoreceptor agonists)
ATC Vet code : QR03CC13: Drugs for obstructive airway disease.
Pharmacodynamic properties
Ventipulmin contains clenbuterol hydrochloride, which is a sympathomimetic amine which preferentially binds to β2 adrenoreceptors on cell membranes of the bronchi. This subsequently activates the enzyme adenylate cyclase in smooth muscle cells, thus providing intense bronchodilating properties and decreasing airway resistance with minimum effect on the cardiovascular system. Ventipulmin has been shown to inhibit histamine release from mast cells in the lungs, and enhance mucociliary clearance in horses.
Pharmacokinetic particulars
After oral administration in horses, clenbuterol is readily absorbed and maximum plasma concentrations reached within 2 hours of dosing. Steady state level in plasma is reached after 3-5 days treatment and range from 1.0 – 2.2 ng/ml.
The substance is rapidly distributed in tissues and metabolised primarily by the liver. Clenbuterol is the main excretory product and approximately 45% of the dose is eliminated unchanged in the urine. The kidneys excrete 70 – 91% of the total dose, and the remainder is eliminated in the faeces (6 – 15%).