Testing Drugs In Vivo
Some in vivo tests can be carried out on normal animals. In vivo testing has always been a source of contention amongst animal rights protesters. In vivo testing is essential to establish whether a candidate drug can reach its intended target in a living system, have the desired physiological effect, and have no undesirable side effects. In order to test anticancer drugs, tumors have been grafted onto mice. The drug is then injected into the mouse and the animal is studied to see whether the tumor stops growing or regresses. However, if the drugs are given intravenously in small doses to a test animal, they dilate the blood vessels as expected but cause an increase in heart rate. The potency of a drug refers to the amount of drug required to achieve a defined biological effect. The dose-response curves for a drug’s therapeutic and lethal effects can be compared to determine whether the therapeutic ratio is safe or not.