Which of the following is useful in treatment of trigeminal neuralgia:

Correct Answer: D

Rationale: Carbamazepine (choice D), an anticonvulsant, treats trigeminal neuralgia by stabilizing sodium channels, reducing nerve firing. Phenylbutazone (choice A), an NSAID, and Morphine (choice B), an opioid, aren't first-line. Atropine (choice C), an anticholinergic, is irrelevant. Carbamazepine is the standard therapy.

Correct Answer: C

Rationale: Phenytoin follows nonlinear (saturation) kinetics meaning small dose increases can cause disproportionate rises in blood levels.

Correct Answer: B

Rationale: Acetaminophen is not an NSAID and does not cause gastric ulceration.

Correct Answer: A

Rationale: Tramadol has dual mechanisms, affecting opioid receptors and inhibiting serotonin/norepinephrine reuptake.

Correct Answer: C

Rationale: Thioridazine has been associated with QT prolongation and a higher risk of cardiac arrhythmias.