Clinical Pharmacy Flashcards

A patient on warfarin is started on fluconazole. What is the expected pharmacokinetic interaction?

Answer: Fluconazole inhibits CYP2C9, increasing warfarin levels and bleeding risk

Fluconazole is a potent CYP2C9 inhibitor that reduces warfarin metabolism, raising INR and bleeding risk.

Which parameter best describes the time required to reach steady-state plasma concentration?

Answer: Approximately 4-5 half-lives

Steady state is reached after approximately 4-5 half-lives regardless of dose or dosing interval.

A patient with a serum creatinine of 2.4 mg/dL requires vancomycin dosing. What adjustment is necessary?

Answer: Reduce dose frequency due to decreased renal clearance

Vancomycin is renally eliminated, so impaired renal function requires extending the dosing interval to prevent toxicity.

A pharmacist reviews a medication therapy management (MTM) encounter. Which of the following is a medication-related problem?

Answer: Unnecessary drug therapy with no medical indication

Unnecessary drug therapy — taking a medication without a valid clinical indication — is a recognized category of medication-related problems in MTM.

Which electrolyte imbalance is most commonly associated with loop diuretic use?

Answer: Hypokalemia

Loop diuretics inhibit the Na-K-2Cl transporter, increasing urinary potassium loss and causing hypokalemia.

A patient taking lithium presents with nausea, tremor, and a serum lithium level of 1.9 mEq/L. What is the appropriate action?

Answer: Hold lithium and consider dialysis if symptoms worsen

A lithium level above 1.5 mEq/L with symptoms indicates toxicity; holding the drug and monitoring for dialysis need is appropriate.

Which statement best describes pharmacodynamic tolerance?

Answer: Decreased receptor sensitivity with repeated drug exposure

Pharmacodynamic tolerance occurs when receptors downregulate or become desensitized, reducing drug effect at the same concentration.