Medical Pharmacology: Pharmacodynamics Practice Questions
Choose the correct answer for each question.
Characteristics of phase I drug metabolizing reactions include conversion of the parent drug into a less polar, more lipid soluble metabolite.
True
False
Phase I drug metabolizing reactions often introduce functional groups such as -OH, -SH, or -NH2 into the parent drug.
True
False
Metabolites generated by phase I drug biotransformation may exhibit:
Loss of drug activity
Reduced drug activity
Increased drug activity
A & B
B & C
A & C
A, B & C
Concerning phase I drug biotransformation:
Phase
I metabolites, if adequately polar, may be excreted easily.
Many phase
I metabolites not adequately polar for rapid elimination undergo an additional reaction involving conjugation with another substrate thus promoting excretion.
Both
Neither
Phase
II metabolism is characterized by "conjugation or synthetic" reactions.
True
False
Isoniazid (INH,isonicotinylhydrazide), at the hydride moiety, is directly conjugated forming an N-acetyl form, initially skipping entirely phase I metabolism.
True
False
The N-acetyl conjugate of isoniazid undergoes a phase I hydrolysis reaction yielding isonicotinic acid. In this example, a phase II reaction precedes the phase I reaction.
True
False
The principal organ for drug metabolism:
Kidney
Liver
Lung
Brain
Midazolam (Versed) is about 50% metabolized in the intestine.
True
False
Drugs that are absorbed from the small intestine and transported prior to any metabolic change via the portal system to the liver and there undergo substantial metabolism are said to exhibit a first-pass effect.
