Which of the following drugs is used in the treatment of Parkinsonian disorders?

Correct Answer: B

Rationale: The correct answer is B: Selegiline. Selegiline is a monoamine oxidase inhibitor used in the treatment of Parkinsonian disorders by increasing dopamine levels in the brain. Phenytoin (A) is an anticonvulsant, not used for Parkinson's. Haloperidol (C) is an antipsychotic, may worsen Parkinson's symptoms. Fluoxetine (D) is an antidepressant, not specific for Parkinson's treatment. Therefore, Selegiline is the most appropriate choice due to its mechanism of action in increasing dopamine levels to alleviate Parkinsonian symptoms.

Correct Answer: A

Rationale: The correct answer is A: Carbamazepine. Carbamazepine has a dual mechanism of action, functioning as both an antiseizure medication and an analgesic. It is commonly used to treat neuropathic pain and trigeminal neuralgia. Carbamazepine's analgesic properties stem from its ability to block voltage-gated sodium channels, reducing neuronal excitability and pain transmission. Summary of other choices: B: Ethosuximide - Primarily used for absence seizures, lacks analgesic properties. C: Phenytoin - Effective against various seizure types but does not have significant analgesic effects. D: Clonazepam - A benzodiazepine used as an antiseizure medication, but does not possess analgesic properties.

Correct Answer: A

Rationale: Step-by-step rationale: 1. Monoamine Oxidase A (MAO-A) is an enzyme responsible for metabolizing neurotransmitters such as norepinephrine, serotonin, and tyramine. 2. MAO-A specifically targets norepinephrine and serotonin, making choice A correct. 3. Choices B, C, and D are incorrect as they incorrectly describe the functions and selectivity of MAO-A. In summary, MAO-A is responsible for norepinephrine, serotonin, and tyramine metabolism, making choice A the correct answer.

Correct Answer: C

Rationale: The correct answer is C because cordiamine does not decrease aortic and coronary flow; instead, it actually increases coronary flow. Cordiamine stimulates the CNS, facilitates movement coordination, acts as a respiratory analeptic, and counteracts central depression from other drugs. Choice A is incorrect as cordiamine does stimulate the CNS and facilitates movement coordination. Choice B is incorrect as cordiamine is indeed a respiratory analeptic of mixed action. Choice D is incorrect as cordiamine does counteract central depression from other drugs like barbiturates.

Correct Answer: C

Rationale: The correct answer is C because sharp swings from a cheerful mood to an aggressive state are not typically associated with barbiturate intoxication. Barbiturates generally depress the central nervous system, leading to symptoms such as stupor, confusion, and slowed thinking. Choice A includes symptoms like vertigo and myasthenia, which can be experienced during barbiturate intoxication. Choice B includes symptoms like perceptual distortions, behavior changes, and speech excitation, which are commonly seen in barbiturate intoxication. Choice D mentions sleep with subsequent weakness and headaches, which are also common symptoms of barbiturate intoxication. Overall, the incorrect choices describe symptoms that align with barbiturate intoxication, making C the outlier.