Route of administration of pamidronate is:

Correct Answer: D

Rationale: The correct answer is D: Intravenous. Pamidronate is a bisphosphonate used to treat bone diseases like osteoporosis. Intravenous route ensures rapid and complete absorption, leading to optimal therapeutic effects. Oral administration (A) would result in poor bioavailability. Subcutaneous (B) and intranasal (C) routes are not commonly used for pamidronate due to inconsistent absorption and inadequate therapeutic levels. Therefore, intravenous administration is the preferred route for pamidronate to achieve the desired clinical outcomes.

Correct Answer: A

Rationale: The correct answer is A: Inhibition of transpeptidation in the bacterial cell wall. Penicillins work by inhibiting the enzyme transpeptidase, which is involved in the cross-linking of peptidoglycan chains in the bacterial cell wall. This leads to weakened cell walls, causing bacterial cell lysis. Choices B, C, and D are incorrect because penicillins do not inhibit beta-lactamase (choice B), activate endogenous proteases to destroy the cell wall (choice C), or activate endogenous phospholipases altering cell membrane permeability (choice D). The primary mechanism of action of penicillins is through interfering with cell wall synthesis, making choice A the correct answer.

Correct Answer: A

Rationale: Nitrofurantoin is the correct answer because it is a nitrofurane derivative with antibacterial properties, commonly used to treat urinary tract infections. Trimethoprim, Ciprofloxacin, and Nystatin are not nitrofurane derivatives and have different mechanisms of action, making them ineffective for this purpose.

Correct Answer: B

Rationale: The correct answer is B: Rimantadine. Rimantadine inhibits the uncoating of viral RNA by preventing the release of viral RNA into the host cell. This disrupts the replication process of the virus. Vidarabine (A) inhibits viral DNA polymerase, not viral RNA uncoating. Acyclovir (C) inhibits viral DNA polymerase as well. Didanozine (D) is an antiretroviral drug used in HIV treatment, not for inhibiting viral RNA uncoating.

Correct Answer: C

Rationale: The correct answer is C: Increased capacitance of systemic veins. Nitrates cause vasodilation, leading to increased venous capacitance, reducing preload and myocardial oxygen demand. Decreased ejection time (A) and decreased arterial pressure (D) are actually beneficial effects of nitrates, as they reduce cardiac workload. Increased cardiac rate (B) is not a common adverse effect of nitrates in the treatment of exertional angina.