Which of the following direct-acting drugs is a relatively pure alfa agonist, an effective mydriatic and decongestant and can be used to raise blood pressure?

Correct Answer: C

Rationale: Rationale: 1. Phenylephrine is a relatively pure alpha agonist, constricts blood vessels, and increases blood pressure. 2. It is an effective mydriatic due to its alpha-adrenergic effects. 3. Phenylephrine is a decongestant by constricting nasal blood vessels. 4. Epinephrine and norepinephrine are non-selective agonists with more diverse effects. 5. Ephedrine acts on both alpha and beta receptors, making it less specific for raising blood pressure.

Correct Answer: D

Rationale: The correct answer is D because an ideal hypnotic agent should have all the qualities listed in choices A, B, and C. Rapid onset and sufficient duration of action ensure quick and long-lasting sleep induction. Minor effects on sleep patterns indicate minimal disruption to natural sleep cycles. Minimal "hangover" effects mean fewer side effects upon waking up, promoting overall well-being. Therefore, having all these qualities makes a hypnotic agent ideal for promoting healthy and restful sleep.

Correct Answer: D

Rationale: The correct answer is D: Lorazepam. Lorazepam is a benzodiazepine receptor agonist, which enhances the inhibitory effect of GABA in the brain, reducing neuronal excitability and preventing seizures. Phenobarbital (A) acts by enhancing GABAergic transmission but is not a benzodiazepine. Phenytoin (B) works by blocking sodium channels. Carbamazepine (C) also blocks sodium channels but is not a benzodiazepine receptor agonist. Therefore, D is the correct answer as it directly acts on the benzodiazepine receptor to control seizures.

Correct Answer: D

Rationale: The correct answer is D because all of the mentioned regions are involved in the transmission of pain. The limbic system processes emotions related to pain. The thalamus relays sensory information to the cortex. The substantia gelatinosa in the spinal cord regulates pain signals. Each region plays a crucial role in the pain pathway, from perception to emotional response. Choices A, B, and C are incorrect because each region mentioned is directly involved in pain transmission.

Correct Answer: D

Rationale: The correct answer is D because severe methanol poisoning requires a multi-modal approach. Dialysis enhances methanol removal. Alkalinization helps counteract metabolic acidosis. Suppressing metabolism by alcohol dehydrogenase prevents the formation of toxic products. Therefore, all options (A, B, and C) are necessary for effective treatment of severe methanol poisoning. Other choices are incorrect as they do not address the multiple facets of methanol toxicity.