Clenbuterol hydrochloride is a beta-2 adrenergic agonist bronchodilator drug that acts on receptors in the lungs to relax the muscles of the lower small airways to cause dilation of these airways. 

VentipulminÒ is the only registered product for the treatment of inflammatory airway disease (IAD) (also known as equine asthma) and other respiratory conditions in horses, characterised by constriction of the lower airways of the lungs. 

Clenbuterol administration can be associated with some immediate adverse effects such as an increased heartrate, sweating and muscle tremors. In the longer term, clenbuterol administration is associated with potentially adverse effects on bone strength, sweating, the immune system, and the heart muscle. 

One major side effect of regulatory significance is the effect clenbuterol has on a horse’s metabolism where it acts a repartitioning agent; it reduces body fat percentage and increases muscle weight, thereby mimicking the effects of androgenic anabolic steroids. These actions are interpreted as having a possible ergogenic (performance-enhancing) effect. 

Specific requirements for use: 

1. The use of clenbuterol shall be limited to horses which have a documented clinical diagnosis of airway disease indicating the need for its therapeutic use. 

2. The diagnosis, as determined by a veterinarian must be accurately recorded in the Veterinary Treatment Register (VTR). 

3. Only VentipluminÒ Granules which is registered for use in horses in South Africa, may administered. No compounded medications shall be permitted for use. 

4. It shall not be administered for more than 14 consecutive days and in accordance with the manufacturer’s guidelines. 

5. A minimum withdrawal period of 30 days shall apply between the last dose of a course of treatment and the day of the race. 

6. There shall be no more than two courses of treatment (each a maximum of 14 consecutive days) permitted in any six-month period, with an interval of not less than 30 days between courses.

Alternative therapies

Where possible, alternative veterinary therapies and management tools should be used in place of clenbuterol. These alternatives to clenbuterol are just as effective, but with less systemic effects or side effects. Inhaled/nebulised treatments are far more direct and reduce the incidence of unwanted systemic effects. 

Corticosteroids (anti-inflammatory medication) administered by the inhaled route are the most effective means of treating horses with IAD, with mucolytic agents used if required, in addition to environmental management to reduce exposure to allergens. 

If short-term relief of bronchoconstriction is required, as an alternative to clenbuterol there are other beta-2 agonist bronchodilator drugs and anticholinergic bronchodilator drugs available as inhaled medications such as ipratropium and salbutamol (albuterol). 

Amended 24/04/2024