Prescription drug dosage is based typically on body weight. Drugs come with a recommended dose in milligrams or micrograms per kilogram of body weight, and that is used in conjunction with the patient’s body weight to determine a safe dosage.Click to see full answer. Similarly, what is drug dosing? More about Dosage and Administration The dose is the amount of drug taken at any one time. The dosage regimen is the frequency at which the drug doses are given. Examples include 2.5 mL twice a day, one tablet three times a day, one injection every four weeks.One may also ask, how is drug potency measured? Overview Efficacy. maximum effect that a drug can produce regardless of dose. Potency. amount of a drug that is needed to produce a given effect. e.g., EC50 is the concentration or dose of drug that causes 50% of maximum effect. determined by affinity of drug for receptor and number of receptors available. In this regard, how do vets calculate drug doses? On the basis of these three factors, the drug dosage is calculated as follows: Animal weight (kg) x dosage (mg/kg) / concentration of drug (mg/ml) = drug volume in ml or cc. Dosage calculation Estimated weight of the animal. The dosage recommended for the species. Concentration of the drug used. What is the strength of a drug?Strength is the amount of drug in a given dosage form, for example, 500 mg/tablet. • Potency refers to the relative strengths of medications that can produce the same effect. The drug with the. lowest strength to produce the effect is said to be the most potent.