PHARMACODYNAMICS

1. Pharmacodynamics is primarily concerned with:

• A. How the body absorbs, distributes, metabolizes, and excretes drugs

• B. The movement of drugs across biological membranes

• 
  C. The effects of drugs on the body and their mechanism of action

• D. The process of drug formulation

Which term refers to the drug concentration that produces 50% of the maximum effect?

• A. ED₅₀

• B. LD₅₀

• C. TD₅₀

• D. MEC

The therapeutic index (TI) of a drug is defined as:

• A. LD₅₀ ÷ ED₅₀

• B. ED₅₀ ÷ LD₅₀

• C. TD₅₀ ÷ ED₅₀

• D. IMY ÷ TCA

Which statement is TRUE regarding potency and efficacy?

• A more potent drug always has higher efficacy

• Efficacy is independent of potency

• Potency measures the maximum effect of a drug

• Efficacy is determined by drug concentration needed to produce effect

A drug has TD50 = 120 mg and ED50 = 40 mg. TI = ?

• A. 2

• B. 3

• C. 4

• D. 6

If Drug A has EC50 = 2 mg and Drug B has EC50 = 10 mg (same Emax), then:

• A. A is less potent

• B. B is more potent

• C. A is more potent

• D. They have equal potency

The maximum effect a drug can produce is:

• A. Potency

• B. Efficacy

• C. Affinity

• D. Bioavailability

Which drug is safer?
Drug A: TI = 4
Drug B: TI = 10

• A. Drug A

• B. Drug B

• C. Equal

• D. Need LD50 to decide

If LD50 = 200 mg and ED50 = 25 mg, TI = ?

• A. 4

• B. 6

• C. 8

• D. 10

A drug has ED50 = 5 mg and TD50 = 50 mg. TI = ?

• A. 2

• B. 5

• C. 10

• D. 20