Nokea
The patient is taking a 2-mg dose of ropinerol XR. The drug has a half-life of 12 hours. How long will it be before only 0.25 mg of this drug remains in the patient's system?
Correct Answer: B
Rationale: The half-life of a drug is the time it takes for the amount of drug in the body to decrease to half of the peak level it previously achieved. At 12 hours there will be 1 mg of the drug available to the body. At 24 hours there will be 0.5 mg, at 36 hours there will be 0.25 mg, at 48 hours there will be 0.125 mg, and at 60 hours there will be 0.0625 mg.