Which of the following drug-related adverse effects was most likely decreased by hydrocortisone?

Correct Answer: D

Rationale: The correct answer is D: Infusion reaction. Hydrocortisone is a corticosteroid that has anti-inflammatory and immunosuppressive properties, which can help decrease infusion reactions such as fever, chills, and allergic reactions during drug administration. It works by suppressing the immune response that triggers these reactions. Red man syndrome (A) is associated with vancomycin use, nephrotoxicity (B) is related to kidney damage caused by certain drugs, and hepatotoxicity (C) refers to liver damage from drugs. These adverse effects are not directly impacted by hydrocortisone's mechanism of action.

Correct Answer: B

Rationale: The correct answer is B: Inhibiting the reuptake of serotonin and norepinephrine. Tramadol is a centrally acting opioid analgesic that exerts its effects through weak opioid receptor binding and inhibition of serotonin and norepinephrine reuptake. This dual mechanism of action contributes to its analgesic properties by modulating pain perception in the central nervous system. Option A is incorrect as tramadol's opioid receptor binding is weak compared to other opioids. Option C is incorrect as tramadol does not directly inhibit prostaglandin synthesis like NSAIDs. Option D is incorrect as tramadol does not primarily increase dopamine release.

Correct Answer: A

Rationale: The correct answer is A because hydralazine works by relaxing vascular smooth muscle through a direct vasodilatory effect, leading to decreased systemic vascular resistance and afterload. This relaxation occurs by increasing nitric oxide production, which promotes vasodilation. This mechanism helps reduce the workload on the heart and improve cardiac output in patients with heart failure. Choice B is incorrect because hydralazine does not block beta-1 adrenergic receptors in the heart. Choice C is incorrect because hydralazine does not directly affect sodium excretion in the kidneys. Choice D is incorrect because hydralazine does not inhibit the conversion of angiotensin I to angiotensin II; that is the mechanism of action for ACE inhibitors.

Correct Answer: A

Rationale: The correct answer is A: Oxybutynin. Oxybutynin is an anticholinergic medication that helps relax the bladder muscles, reducing urinary urgency and frequency in overactive bladder. Oxybutynin blocks the action of acetylcholine, a neurotransmitter responsible for bladder contractions. This effect helps control symptoms of overactive bladder. Summary of incorrect choices: B: Loratadine is an antihistamine used for allergies and does not treat overactive bladder symptoms. C: Gabapentin is used for nerve pain and seizures, not specifically for overactive bladder. D: Cyclobenzaprine is a muscle relaxant used for muscle spasms, not for overactive bladder symptoms.

Correct Answer: A

Rationale: The correct answer is A: Phenytoin. Phenytoin is a sodium channel blocker that stabilizes the neuronal membrane by inhibiting repetitive firing of action potentials. This mechanism helps control seizures. Clonazepam (B) acts on GABA receptors, Valproate (C) increases GABA levels, and Gabapentin (D) modulates calcium channels - all different mechanisms not related to stabilizing neuronal membranes for seizure control.