Opioid analgesics provide symptomatic relief of

Correct Answer: D

Rationale: The correct answer is D: All of the above. Opioid analgesics are primarily used for pain relief by acting on the central nervous system to reduce the perception of pain. They can also help suppress cough reflex, making them useful in some cough suppressants. Opioids can also slow down intestinal motility, which can help alleviate diarrhea. Therefore, the correct answer is D as opioids can provide symptomatic relief for pain, cough, and diarrhea. Choices A, B, and C are incorrect because they do not encompass the full range of symptomatic relief that opioids can provide.

Correct Answer: A

Rationale: The correct answer is A: Diazepam. This is because Diazepam is a fast-acting benzodiazepine that helps terminate seizures quickly, making it the drug of choice for status epilepticus. It works by enhancing the effects of the inhibitory neurotransmitter GABA, which helps to calm excessive electrical activity in the brain during a seizure. Phenobarbital (B) and Phenytoin (C) are not recommended as first-line treatments for status epilepticus due to slower onset of action. Valproic Acid (D) is also not the drug of choice for status epilepticus as it is typically used for long-term seizure management rather than acute seizure control.

Correct Answer: A

Rationale: Step-by-step rationale for why the correct answer is A: Topiramate is primarily used for migraine prophylaxis due to its ability to reduce the frequency and severity of migraines. It works by stabilizing electrical activity in the brain. The other choices are incorrect because topiramate is not typically used for acute seizures, mood stabilization, or pain management. It is important to differentiate between the specific indications for each medication to ensure appropriate treatment.

Correct Answer: A

Rationale: The correct answer is A: Sedative-hypnotic. Zolpidem is used to treat insomnia by promoting sleep onset and improving sleep maintenance. It acts on the central nervous system to enhance the inhibitory neurotransmitter GABA. This classification is based on its pharmacological effects and mechanism of action. B: Anti-anxiety drug - Zolpidem is not primarily indicated for anxiety disorders but for insomnia. C: Anti-convulsant - Zolpidem is not used to prevent or control seizures, so it is not classified as an anti-convulsant. D: Muscle relaxant - Zolpidem does not have a direct effect on muscle relaxation, so it is not classified as a muscle relaxant.

Correct Answer: B

Rationale: The correct answer is B: Fraction of an unchanged drug reaching the systemic circulation following any route of administration. Bioavailability refers to the proportion of an administered dose of unchanged drug that reaches the systemic circulation. This is crucial in determining the effectiveness of a drug. Option A is incorrect because bioavailability is not specifically related to the amount excreted in urine. Option C is incorrect as it refers to permeability through the blood-brain barrier, which is a different concept. Option D is incorrect as it pertains to plasma protein binding, which is not the same as bioavailability. In summary, bioavailability is about the amount of a drug that reaches systemic circulation intact, making option B the correct choice.