© 2004 by Thomson Delmar Learning, a part of the Thomson Corporation. Fundamentals of Pharmacology for Veterinary Technicians Chapter 2 Veterinary Drug Development and Control

© 2004 by Thomson Delmar Learning, a part of the Thomson Corporation. Stages of Veterinary Drug Development In the United States, new veterinary drugs must go through a series of tests mandated by the FDA There are four major steps in drug development: –Synthesis/discovery of a new drug compound –Safety/effectiveness evaluation –Submission and review of the New Animal Drug Application (NADA) –Postmarketing surveillance stage

© 2004 by Thomson Delmar Learning, a part of the Thomson Corporation. Synthesis/Discovery of a New Drug Compound Potential therapeutic agents must go through a series of tests Step 1: Preliminary studies: determine the intended effect and possible toxic side effects May include computer modeling, testing in lab media, or testing on bacteria or fungi

© 2004 by Thomson Delmar Learning, a part of the Thomson Corporation. Synthesis/Discovery of a New Drug Compound Step 2: Preclinical studies: determine a drugs safety and effectiveness –Short-term and long-term tests –Check for immediate drug reactions, organ damage, reproductive effects, carcinogenicity, and teratogenicity

© 2004 by Thomson Delmar Learning, a part of the Thomson Corporation. Synthesis/Discovery of a New Drug Compound Step 3: Submission and review of the New Animal Drug Application (NADA) –Submit Investigational New Animal Drug (INAD) application for the drug to the FDA –Submit Experimental Use Permit (EUP) for pesticide to the EPA –Submit application for biologics to the APHIS division of the USDA

© 2004 by Thomson Delmar Learning, a part of the Thomson Corporation. Synthesis/Discovery of a New Drug Compound Step 3 (cont.): Submission and review of the New Animal Drug Application (NADA) –If application is approved, clinical trials proceed –Clinical trials are done on target species –Satisfactory clinical trial results allow scientists to file a New Animal Drug Application (NADA) with the FDA, EPA, or USDA –Approval and license are granted for successful drugs

© 2004 by Thomson Delmar Learning, a part of the Thomson Corporation. Synthesis/Discovery of a New Drug Compound Step 4: Postmarketing surveillance stage –The drug company and the government monitor the product as long as the drug is manufactured –This monitoring ensures product safety and efficacy

© 2004 by Thomson Delmar Learning, a part of the Thomson Corporation. Effective and Lethal Doses Effective dose: the amount of the test drug that causes a defined effect in 50% of the animals that receive it –ED 50 Lethal dose: the amount of the test drug that kills 50% of the animals that receive it –LD 50

© 2004 by Thomson Delmar Learning, a part of the Thomson Corporation. Therapeutic Index Therapeutic index is the drug dosage or dose that produces the desired effect with minimal or no signs of toxicity –Also called the margin of safety –Determined by comparing the lethal dose and effective dose of the drug –LD 50 ÷ ED 50 –A wide therapeutic index means that the drug can produce its desired effect without approaching toxicity

© 2004 by Thomson Delmar Learning, a part of the Thomson Corporation. Tests That New Drugs Go Through Systems-oriented screening Evaluation of long-term effects Evaluation of reproductive effects, carcinogenicity, and teratogenicity

© 2004 by Thomson Delmar Learning, a part of the Thomson Corporation. Drug Marketing Systems Direct marketing: drug is purchased directly from the company that makes it Distributors or wholesalers: drug is purchased from the manufacturing company and resold to veterinarians Generic companies: sell drugs that are no longer under patent protection