Indicate a peripheral dopa decarboxylase inhibitor:

Correct Answer: C

Rationale: Rationale: Carbidopa is a peripheral dopa decarboxylase inhibitor. It does not cross the blood-brain barrier and prevents the conversion of levodopa to dopamine in the periphery, increasing levodopa availability in the brain. Tolcapone and Selegiline are central nervous system dopaminergic agents. Clozapine is an atypical antipsychotic used in schizophrenia.

Correct Answer: A

Rationale: Step 1: Antipsychotic drugs primarily act by blocking dopamine receptors, especially D2 receptors. Step 2: Blocking D2 receptors reduces dopamine activity, helping control psychotic symptoms. Step 3: Option A is correct as antipsychotics strongly block postsynaptic D2 receptors. Summary: - B is incorrect as stimulating D2 receptors would worsen psychotic symptoms. - C is incorrect as antipsychotics do not typically block NMDA receptors. - D is incorrect as antipsychotics primarily target dopamine receptors, not 5-HT2 receptors.

Correct Answer: C

Rationale: The correct answer is C. Irreversible MAO inhibitors can lead to hypertensive reactions due to tyramine buildup from food. MAO breaks down tyramine, so inhibition leads to excess tyramine causing dangerous spikes in blood pressure. Respiratory depression (A) and agranulocytosis (D) are not typically associated with MAO inhibitors. While cardiovascular collapse and CNS depression (B) can occur, the high risk is specifically for hypertensive crises due to tyramine interactions.

Correct Answer: D

Rationale: The correct answer is D: Piracetam. Piracetam is a nootropic, which means it enhances cognitive function, memory, and learning. It is not a CNS stimulant like choices A, B, and C. Camphor is a topical analgesic, Pantocrin is an adrenal extract, and Sydnocarb is a stimulant used in treating narcolepsy. Piracetam stands out as a nootropic due to its specific cognitive-enhancing effects, making it the correct choice in this context.

Correct Answer: D

Rationale: The correct answer is D: All of the above. Cocaine, amphetamine, and caffeine are all stimulant drugs that affect the central nervous system, leading to increased alertness, energy, and euphoria. Cocaine is a powerful stimulant derived from the coca plant, amphetamine is a synthetic stimulant commonly used as a prescription medication or illicit drug, and caffeine is a naturally occurring stimulant found in coffee, tea, and other beverages. All three substances have similar effects on the body, making them related to stimulants. Therefore, the correct answer is D as all the options (A, B, and C) are related to stimulants.