A 50-year-old male with chronic pain is prescribed tramadol. Tramadol works by:

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: 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.

Correct Answer: A

Rationale: The correct answer is A: Inhibiting osteoclast-mediated bone resorption. Raloxifene is a selective estrogen receptor modulator (SERM) that works by binding to estrogen receptors in bone tissue, inhibiting osteoclast activity, and reducing bone resorption. This helps to maintain bone density in patients with osteoporosis. Choices B and C are incorrect as raloxifene does not directly promote osteoblast activity or increase calcium absorption in the intestines. Choice D is also incorrect as raloxifene does not inhibit the synthesis of collagen.

Correct Answer: C

Rationale: The correct answer is C: Warfarin. Warfarin is an anticoagulant that helps prevent blood clots, reducing the risk of stroke in patients with atrial fibrillation. It is more effective than aspirin or clopidogrel in preventing stroke in this patient population. Heparin is not typically used for long-term stroke prevention in atrial fibrillation.