OSCE Pharmacology Fundamentals 4

Question 1

A patient with hepatic cirrhosis is started on a drug with high hepatic extraction ratio. What is the expected change in bioavailability?

Accepted Answer

Increased bioavailability due to reduced first-pass metabolism

Answer

High hepatic extraction drugs undergo significant first-pass metabolism; liver disease reduces this extraction, increasing oral bioavailability.

Question 2

Which plasma protein primarily binds acidic drugs such as warfarin and phenytoin?

Accepted Answer

Albumin

Answer

Albumin is the primary plasma protein binding acidic drugs; hypoalbuminemia increases free drug fraction and potential toxicity.

Question 3

A drug has a volume of distribution of 500 L in a 70 kg patient. What does this suggest?

Accepted Answer

Extensive tissue distribution with low plasma concentration

Answer

A large volume of distribution (>42 L) indicates the drug distributes extensively into tissues rather than remaining in plasma.

Question 4

A drug is a prodrug. Which statement best describes a prodrug?

Accepted Answer

An inactive compound converted to its active form after administration

Answer

Prodrugs are pharmacologically inactive until metabolized (typically hepatically) to their active metabolite.

Question 5

Which statement correctly describes a drug with a long half-life (t½)?

Accepted Answer

It takes longer to reach steady state and longer to be eliminated

Answer

Steady state is reached after approximately 4-5 half-lives; a long t½ means both delayed steady state and prolonged elimination after stopping.

OSCE Practice Test