Which of the following drugs is an imidazoline derivative and a potent competitive antagonist at both alfa1 and alfa2 receptors?

Correct Answer: D

Rationale: The correct answer is D: Phentolamine. Phentolamine is an imidazoline derivative and a potent competitive antagonist at both alpha1 and alpha2 receptors. It blocks the effects of norepinephrine at these receptors. Prazosin (A) is an alpha1 antagonist, Labetalol (B) is a non-selective alpha and beta blocker, and Phenoxybenzamine (C) is a non-selective irreversible alpha blocker. Therefore, Phentolamine is the only drug that fits the description provided in the question.

Correct Answer: A

Rationale: The correct answer is A. Barbiturates are used in status epilepticus due to their ability to significantly decrease oxygen utilization by the brain, which helps protect against cerebral edema and ischemia. This is crucial in managing the acute phase of seizures in infants and children. Option B is incorrect because barbiturates have a short onset but prolonged duration of action, making them unsuitable for rapid management. Option C is incorrect as barbiturates can disrupt normal sleep architecture due to their sedative effects. Therefore, the correct choice is A for its specific neuroprotective properties in the context of status epilepticus.

Correct Answer: C

Rationale: Rationale: 1. Bromocriptine is a D2 receptor agonist. 2. Stimulation of D2 receptors helps alleviate Parkinson's symptoms. 3. Sinemet and Levodopa are dopamine precursors but not D2 agonists. 4. Selegiline is a monoamine oxidase inhibitor, not a D2 agonist. In summary, Bromocriptine directly activates D2 receptors, making it the correct choice for antiparkinsonian activity.

Correct Answer: D

Rationale: Alcohol can cause CNS depression by slowing down brain function. It also leads to vasodilatation, widening blood vessels and lowering blood pressure. Additionally, alcohol can induce hypoglycemia by inhibiting glucose production in the liver. Therefore, all choices are correct, making option D the correct answer. Other choices are incorrect because they individually do not encompass all the effects of alcohol consumption.

Correct Answer: C

Rationale: The correct answer is C: Chlorpromazine. Chlorpromazine is a phenothiazine aliphatic derivative because it belongs to the phenothiazine class of antipsychotic drugs and has an aliphatic side chain. Thiothixene (A) is a thioxanthene derivative, not a phenothiazine. Risperidone (B) is an atypical antipsychotic, not a phenothiazine. Clozapine (D) is a dibenzodiazepine derivative, not a phenothiazine. Therefore, Chlorpromazine is the only option that fits the criteria of being a phenothiazine aliphatic derivative.