Respiratory diseases are second only in frequency to lameness as a reason for requesting veterinary treatment in equine practice. Coughs, wheezing, nasal discharges and poor exercise capacity are typical features shared by the many types of respiratory disease. It is regrettable, although understandable, that pharmaceutical companies tend to direct more funding and effort into producing new drugs for human medicine than for veterinary medicine and consequently our medical colleagues possess a much greater armoury of treatments for respiratory diseases than we do in equine practice.
The widespread use of hand-held inhalers in people suffering from asthma is testament to the highly favourable impact of inhaled drugs in human respiratory medicine. This route of drug administration has been investigated in the horse and is now becoming more popular in equine practice.
In addition to a much greater range of drugs available, the main advantage of inhalation therapy is that the drug is applied directly to the source of the problem (ie. the lungs). This offers advantages in terms of high levels of drug being reached in the lung despite a lower total dosage used in comparison with injection or ‘in feed’ treatment.
No inhaled human drugs have so far been specifically licensed for use in the horse although many trials have been conducted showing their safety and effectiveness. The main problem with this form of therapy in horses is the practicalities of getting the horse to inhale the drug. This is also a problem faced by doctors in the treatment of babies and young children and face-masks were developed to overcome this. As luck would have it, a baby’s face-mask fits neatly over a horse’s nostril and allows the various human products to be administered easily and efficiently to the vast majority of horses. This has consequently unveiled a considerable untapped source of potential medications for use in horses which has completely altered the way we currently approach the treatment of equine respiratory diseases.
