USE OF BODY-SURFACE AREA (BSA)-BASED DOSAGES TO CALCULATE CHEMOTHERAPEUTIC DRUG DOSE IN DOGS - I - POTENTIAL PROBLEMS WITH CURRENT BSA FORMULAS

The dose of most cancer chemotherapeutic drugs administered to dogs is calculated on the basis of estimated body surface area (BSA); however , results of some chemotherapy trials have revealed that this dosing m ethod increases toxicosis in small dogs. The current formula used to e stimate BSA in dogs may be inaccurate or the assumption that BSA corre lates with chemotherapeutic drug exposure may be unfounded. Results pr esented in this review suggest that canine BSA estimates may be inaccu rate because the values for the constant (K) and exponent (a) in the f ormulae (BSA = K . W-a) are incorrect or because a linear parameter su ch as body length is lacking from the formulae. Results that suggest t he relationship between BSA and the physiologic/pharmacologic factors that influence drug exposure may not be closely correlated are also pr esented. Studies are warranted to determine whether there are dosing m ethods that normalize chemotherapeutic drug toxicity in dogs.