PSA Pharmacology Principles

Question 1

What is bioavailability?

Accepted Answer

The fraction of an administered drug dose that reaches systemic circulation in active form

Answer

Bioavailability measures what proportion of the administered drug reaches the bloodstream in active form. IV drugs have 100% bioavailability; oral drugs vary.

Question 2

What is a drug's half-life?

Accepted Answer

The time required for the drug's plasma concentration to decrease by 50%

Answer

Half-life determines dosing frequency: drugs with short half-lives need more frequent dosing, while long half-life drugs can be given less often.

Question 3

What is the therapeutic index?

Accepted Answer

The ratio between the toxic dose and the therapeutic dose — drugs with a narrow index require careful monitoring

Answer

A narrow therapeutic index means the difference between an effective dose and a toxic dose is small, requiring careful dosing and monitoring (e.g., warfarin, lithium, digoxin).

Question 4

What is the difference between pharmacokinetics and pharmacodynamics?

Accepted Answer

Pharmacokinetics is what the body does to the drug; pharmacodynamics is what the drug does to the body

Answer

Pharmacokinetics covers absorption, distribution, metabolism, and excretion (ADME). Pharmacodynamics covers the drug's mechanism of action and effects on the body.

Question 5

What does 'loading dose' mean?

Accepted Answer

A higher initial dose given to rapidly achieve therapeutic drug levels

Answer

A loading dose is an initially higher dose designed to quickly bring drug levels into the therapeutic range, followed by lower maintenance doses.

(PSA) Prescribing Safety Assessment Practice Test

(PSA) Prescribing Safety Assessment Practice Test

PSA Pharmacology Principles