An agent used in treatment of infertility that blocks hypothalamic estrogen receptors preventing normal feedback inhibition of FSHRH & LHRH:

Correct Answer: A

Rationale: Clomiphene blocks hypothalamic estrogen receptors, increasing GnRH, FSH, and LH to stimulate ovulation in infertility.

Correct Answer: A

Rationale: Alendronate (bisphosphonate) causes esophagitis and can impair renal function if not cleared properly.

Correct Answer: D

Rationale: Leuprolide in continuous form (not pulsatile) treats prostate cancer by suppressing testosterone. Ganirelix, flutamide, and degarelix are also used.

Correct Answer: D

Rationale: ADH antagonists (e.g., tolvaptan, conivaptan) treat SIADH by increasing water excretion, risking hyponatremia. Tolvaptan is V2-selective, conivaptan is V1/V2, demeclocycline is used (not replaced), and tolvaptan is oral.

Correct Answer: D

Rationale: Penicillins are safe in pregnancy, cross the BBB in meningitis, and are prolonged by probenecid, but they’re not mixed with aminoglycosides in one bolus due to inactivation; they’re given separately.