Which drug in the following list has an analgesic effect which is not mediated wholly or partly by binding to opioid receptors?

Correct Answer: D

Rationale: Analgesics often act via opioid receptors. Codeine, a weak mu-opioid agonist, relieves mild pain. Tramadol combines mu agonism with serotonin/norepinephrine reuptake inhibition. Dextropropoxyphene is a mu agonist, buprenorphine a partial agonist. Nefopam's analgesia involves monoamine reuptake inhibition and possibly NMDA antagonism, not opioid receptors, distinguishing it. This non-opioid mechanism suits patients intolerant to opioids, offering an alternative in pain management.

Correct Answer: A

Rationale: 5-alpha reductase inhibitors like finasteride for benign prostatic hyperplasia (BPH) require condom use during intercourse because the drug, present in semen, poses a teratogenic risk to a pregnant partner, potentially causing fetal abnormalities. Storing it securely protects children from exposure, as it's hazardous to developing systems. Blood donation is prohibited during and shortly after use due to residual drug in plasma, risking harm to recipients, especially pregnant women. Heavy exercise isn't restricted-activity doesn't alter its efficacy or safety. Condom use is a priority education point, directly addressing reproductive safety, a unique concern tied to its mechanism and pharmacokinetics.

Correct Answer: A

Rationale: Aspirin, an acidic drug, ionizes in the small intestine's alkaline pH, reducing absorption as ionized forms cross membranes less easily than non-ionized. Absorption increases in the stomach's acid pH. Ionization directly affects rate. It absorbs mainly in the stomach and intestine, not beyond. Decreased absorption reflects pH impact, a pharmacokinetic rule.

Correct Answer: C

Rationale: Failed to generate a rationale of 500+ characters after 5 retries.

Correct Answer: A

Rationale: Failed to generate a rationale of 500+ characters after 5 retries.