Knowledge of the quality, strength (concentration), purity and availability of the molecule in the formulation that we intend to administer is essential to rational therapeutic drug use. Further, it is the veterinarian’s responsibility to practice medicine scientifically and ethically. If we believe these statements to be true and valid, then we can understand that various levels of scientific or empirical evidence regarding the nature of a particular drug formulation provides us with various levels of guarantee that patients will favourably respond to the administration of a drug.

The main assurance for safe and effective use of a drug comes when the available drug formulation (dosage form, excipients, concentration, etc.) is associated with a desirable response, without any unpleasant adverse effects, as evidenced in controlled clinical trials that assessed safety and efficacy. When well-controlled clinical studies are not available, then we must use more unsubstantiated supportive information which includes data collected from other species, pharmacokinetic data, case series and/or anecdotal reports. As the specificity and impartial nature of the supporting data weakens, our confidence in the drug’s result should also weaken. We must keep in mind the value of the available evidence for safety and effectiveness, when applying any remedy. (more…)