Correct Answer: B

Rationale: Atenolol, a beta-blocker, is not typically associated with tachycardia. Instead, drug toxicity of Atenolol is more commonly linked to bradycardia due to its beta-blocking effects on the heart's electrical conduction system. Symptoms of Atenolol toxicity may include heart failure (CHF), AV block, and a sedative appearance, but not tachycardia.

Correct Answer: B

Rationale: Warfarin primarily affects the liver where it inhibits the synthesis of clotting factors.

Correct Answer: B

Rationale: When a drug name ends in the suffix -navir, it indicates that the drug is a protease inhibitor. Protease inhibitors are commonly used in antiviral therapy to treat infections by inhibiting viral replication. Therefore, the correct answer is B: Protease inhibitor.

Correct Answer: D

Rationale: Fluoroquinolones are known to be associated with tendon dysfunction or rupture. These drugs can weaken the tendons, leading to potential issues such as tendonitis or even tendon rupture. It is essential for healthcare providers to be cautious when prescribing fluoroquinolones, especially in patients who may be at higher risk for tendon-related complications.

Correct Answer: D

Rationale: Potassium-sparing diuretics exert their primary effects on the distal convoluted tubule in the kidney. By acting on this specific part of the nephron, these diuretics promote sodium excretion while sparing potassium, thus helping to maintain potassium levels in the body. This mechanism differs from other diuretics that may cause potassium loss as a side effect. Understanding the site of action of potassium-sparing diuretics is crucial in clinical practice for managing conditions like hypertension and edema where diuresis is necessary without the risk of hypokalemia.