The primary care NP should understand that a drug is at a ...

[jessicacav]

The primary care NP should understand that a drug is at a therapeutic level when it is:
 
  a. at peak plasma level.
  b. past 4 or 5 half-lives.
  c. at its steady plasma state.
  d. between minimal effective concentration and toxic levels.

Question 2

A patient is taking drug A and drug B. The primary care NP notes increased effects of drug B. The NP should suspect that in this case drug A is a cytochrome P450 (CYP450) enzyme:
 
  a. inhibitor.
  b. substrate.
  c. inducer.
  d. metabolizer.

[efwsefaw]

Answer to Question 1

D
The therapeutic range of a drug is the area between the minimal effective concentration and the toxic concentration. Peak plasma level is the highest level the drug reaches and may be well into the toxic range. Steady state occurs when there is a stable concentration of the drug and generally occurs after 4 or 5 half-lives.

Answer to Question 2

A
If drug A is a CYP450 enzyme inhibitor, it decreases the capacity of the enzyme to metabolize drug B, causing more of drug B to be available. A substrate is a drug acted on by the enzyme. If drug B is an enzyme inducer, it would cause increased metabolism of drug A.