Serotonin agonists -- clinical use:

Correct Answer: C

Rationale: The correct answer is C (Both). Serotonin agonists like buspirone are used as anxiolytics by acting on serotonin receptors. Sumatriptan is used for migraines by constricting blood vessels and blocking pain pathways. Therefore, both options A and B are correct. Option D is incorrect because both buspirone and sumatriptan have clinical uses as serotonin agonists.

Correct Answer: A

Rationale: Rationale: Carbamazepine is chemically derived from the tricyclic antidepressant imipramine. It is commonly used as an anti-epileptic medication. Carbamazepine's mechanism of action involves blocking voltage-gated sodium channels in neurons. This helps to stabilize the hyperexcitable neuronal membranes in epilepsy. Ethosuximide and Phenytoin are not derived from tricyclic antidepressants and have different mechanisms of action in treating epilepsy. Therefore, the correct answer is A: Carbamazepine.

Correct Answer: D

Rationale: Step-by-step rationale: 1. Ondansetron is commonly used as an antiemetic, specifically for preventing nausea and vomiting caused by cancer chemotherapy. 2. It works by blocking serotonin receptors in the brain, which helps to alleviate nausea and vomiting. 3. This mechanism of action is specific to antiemetics and not antihistamines, drugs for peptic ulcers, or antiarrhythmics. 4. Therefore, the correct answer is D - Antiemetic for cancer chemotherapy. Summary: - Choice A is incorrect because ondansetron is not an antihistamine. - Choice B is incorrect because ondansetron is not used for treating peptic ulcers. - Choice C is incorrect because ondansetron is not an antiarrhythmic. - The correct answer, D, is supported by the drug's mechanism of action and primary usage as an antiemetic for cancer chemotherapy.

Correct Answer: C

Rationale: The correct answer is C because ketamine can be administered via both intravenous and intramuscular routes. Intravenous administration allows for rapid onset of action, making it ideal for induction of anesthesia. Intramuscular administration provides an alternative option for administration when intravenous access is not available. Options A and B are incorrect because ketamine can be administered via both routes. Option D is incorrect as ketamine can be administered through one or both of the mentioned routes.

Correct Answer: B

Rationale: Phenelzine belongs to the class of MAO inhibitors because it inhibits the enzyme monoamine oxidase, which leads to increased levels of neurotransmitters like serotonin, norepinephrine, and dopamine. This mechanism differs from the other classes listed. Tricyclic antidepressants (A) block the reuptake of neurotransmitters, SSRIs (C) selectively block serotonin reuptake, and atypical antidepressants (D) have diverse mechanisms but don't primarily inhibit MAO. This makes choice B the correct answer.