The concentration of dopamine in the basal ganglia of the brain is reduced in parkinsonism.

Correct Answer: A

Rationale: The correct answer is A: TRUE. In Parkinson's disease, there is a reduction in dopamine levels in the basal ganglia, leading to the characteristic motor symptoms. This is due to the degeneration of dopamine-producing neurons in the substantia nigra. Choice B is incorrect because the statement is true. Choice C (None) and D (All) are incorrect as they do not provide any meaningful explanation.

Correct Answer: C

Rationale: Step-by-step rationale for choice C (Analgin) being the correct answer for possible adverse effect of Methemoglobinemia: 1. Analgin contains metamizole, which can lead to methemoglobinemia by causing the oxidation of hemoglobin. 2. Methemoglobinemia is a condition where hemoglobin is unable to transport oxygen efficiently. 3. Aspirin (choice A), Paracetamol (choice B), and Ketorolac (choice D) do not typically cause methemoglobinemia. Summary: - Choice A (Aspirin) is incorrect because it does not cause methemoglobinemia. - Choice B (Paracetamol) is incorrect because it does not cause methemoglobinemia. - Choice D (Ketorolac) is incorrect because it does not cause methemoglobinemia. - Choice C (Analgin) is correct due to its potential to cause methemoglobinemia through the presence of metamizole.

Correct Answer: D

Rationale: The correct answer is D: Phenelzine. Phenelzine is an irreversible MAO inhibitor that irreversibly binds to and inhibits monoamine oxidase enzymes. This irreversible binding leads to a long-lasting inhibition of MAO activity. Moclobemide (A) is a reversible MAO inhibitor, while Selegiline (B) is a selective irreversible MAO-B inhibitor. Tranylcypramine (C) is a reversible MAO inhibitor. Therefore, Phenelzine is the only irreversible MAO inhibitor among the options provided.

Correct Answer: D

Rationale: The correct answer is D: Gastric ulceration. Caffeine is not typically associated with causing gastric ulcers. Caffeine is actually used as a treatment for migraines due to its ability to constrict blood vessels. It is also used to relieve drowsiness (somnolence) by stimulating the central nervous system. Additionally, caffeine can help improve cardiovascular function and respiratory efficiency, so choices A, B, and C are all potential therapeutic uses of caffeine.

Correct Answer: A

Rationale: The correct answer is A: TRUE. Opioid withdrawal symptoms typically start 8-10 hours after the last dose due to the short half-life of opioids. This timing aligns with the onset of symptoms such as anxiety, sweating, and muscle aches. The other choices are incorrect. Choice B is false because the onset of opioid withdrawal symptoms does not occur immediately after the last dose. Choice C, All, is incorrect as it implies that all choices are correct, which is not the case. Choice D, Null, is also incorrect as it does not provide any relevant information regarding the onset of opioid withdrawal symptoms.