Question

Question 1

Drugs affect the behavior

a. at all tissues that they come in contact with

b. only at the places where they are administered

c. only at their sites of actions

d. by altering the functions of all organs

Question 2

The half-life of a drug is the time it takes to

a. clear half of a drug does from the blood compartment

b. clear half of a drug does from the fat

c. clear half of a drug does from the brain compartment

d. clear half of a drug does form the liver

Question 3

LD50/ED50 is the

a. lethal ratio

b. therapeutic index

c. lethal does

d. effective dose

Question 4

If 5 out of 10 subjects show a specific behavior to a does of a drug, this is

a. ED 60

b. LD 50

c. TI 60

d. ED 50

Answer 1

1. The correct answer is Option A. Drugs affect the behavior at all tissues that they come in contact with. The distribution of drugs is not uniform in the body because tissues receive the drug from the plasma at different rates and intensities.
2. The correct answer is Option A. The half-life of a drug is the time it takes to clear half of a drug does from the blood compartment. It is the total duration where the concentration in the blood plasma is reduced to 50%.
3. The correct answer is Option B. This is known as the therapeutic index. It is the ratio showing the selectivity of a drug to elicit a desired effect.
4. The correct answer is Option D. If 5 out of 10 subjects show a specific behavior to a does of a drug, this is ED 50. ED refers to effective dose whereas LD refers to lethal dose.