Saudi Prometric Pharmacist Pharmaceutical Chemistry and Pharmacology

Question 1

Which functional group is responsible for the beta-lactam antibiotic activity in penicillin?

Accepted Answer

The four-membered beta-lactam ring

Answer

The thiazolidine ring

Answer

The side-chain amide group

Answer

The carboxyl group at position 3

Question 2

Which drug class inhibits HMG-CoA reductase to lower plasma cholesterol?

Accepted Answer

Statins (e.g., atorvastatin)

Answer

Fibrates (e.g., fenofibrate)

Answer

Bile acid sequestrants (e.g., cholestyramine)

Answer

Niacin (nicotinic acid)

Question 3

What is the mechanism of action of aspirin (acetylsalicylic acid)?

Accepted Answer

Irreversible inhibition of cyclooxygenase (COX-1 and COX-2)

Answer

Reversible inhibition of COX-2 only

Answer

Inhibition of phospholipase A2

Answer

Antagonism of prostaglandin receptors

Question 4

Which property of a drug determines its distribution to tissues with high lipid content such as the brain?

Accepted Answer

High lipophilicity (lipid solubility)

Answer

High molecular weight

Answer

Low protein binding

Answer

High pKa (strongly basic)

Question 5

A pharmacist is reviewing a prescription for phenytoin. Which metabolic pathway is responsible for phenytoin's non-linear pharmacokinetics?

Accepted Answer

Saturable (zero-order at high doses) CYP2C9-mediated hydroxylation

Answer

First-order elimination via renal excretion

Answer

Linear CYP3A4 metabolism

Answer

Unchanged renal elimination

Question 6

Which chemical property allows a drug to be absorbed in the acidic environment of the stomach?

Accepted Answer

Being a weak acid (low pKa) so it is un-ionized in acid — non-ionized form is lipid-soluble

Answer

Being a strong base with pKa >10

Answer

Being highly ionized at gastric pH

Answer

Having a very high molecular weight