WDA Allometric Scaling

A method of adjusting drug doses for size and species specific metabolic rates.

Disclaimer: This app is only meant to adjust dosages for size and metabolic rate of an animal patient, it is not a substitute for good veterinary judgement, an established Dr.-client-patient relationship, due diligence in knowing the literature on pharmacology and patient idiosyncrasies, and carries no guarantee of results.

The body mass of veterinary patients may vary as much as eight orders of magnitude from the smallest 2 gram hummingbird to the 180,000 kg blue whale. Add to that, the metabolic rate of a small bird may be ten times that of a reptile or amphibian. In human medicine, there is much less variation in metabolic rate, and only two orders of magnitude in mass from an infant to a sumo wrestler. No wonder determining the optimal therapeutic dose of treatment or anesthetic drugs for captive and free-living wildlife and exotic pets is so difficult and fraught with hazards. Unless variations in mass and metabolic rates (allometric scaling) are utilized, ineffective treatment due to underdosage, or toxic or fatal results due to overdosage, are significant possibilities when treating animal species and using pharmaceuticals with which you do not have extensive experience, and research based dosage rates.

Allometric scaling is a method of adjusting drug doses or dosage rates for extremes of size and species specific metabolic rates. It was championed by Dr. Charles Sedgewick in the 1990’s and taught to many Tufts graduates. But it required some fairly sophisticated mathematics. Now, with Chuck’s blessing, the Wildlife Disease Association is providing this to you in the form of an app for use on your phone.