Which of the following analgesics is a phenanthrene derivative?

Correct Answer: B

Rationale: The correct answer is B: Morphine. Morphine is a phenanthrene derivative as it belongs to the opioid class of analgesics derived from the phenanthrene nucleus. Fentanyl (A) is a synthetic opioid, not derived from phenanthrene. Methadone (C) is a synthetic opioid unrelated to phenanthrene. Pentazocine (D) is a mixed opioid agonist-antagonist, not a phenanthrene derivative. Therefore, based on the chemical structure and classification, morphine is the only phenanthrene derivative among the options.

Correct Answer: B

Rationale: The correct answer is B: Decrease catecholamine-related activity. Lithium is known to decrease the activity of catecholamines, including norepinephrine and dopamine, by inhibiting their release and synthesis. This action helps in stabilizing mood and is why lithium is commonly used in the treatment of bipolar disorder. A: Stimulating dopamine and beta-adrenergic receptors is incorrect as lithium does not directly affect these receptors. C: Stimulating the development of dopamine receptor supersensitivity is incorrect as lithium does not enhance dopamine receptor sensitivity. D: Decreasing cholinergic activity is incorrect as lithium primarily affects catecholamines, not cholinergic neurotransmission.

Correct Answer: D

Rationale: Step 1: Amphetamine is a powerful stimulant of the CNS, increasing alertness and energy levels. Step 2: It stimulates the medullar respiratory center, enhancing breathing, and acts as an analeptic agent. Step 3: Amphetamine increases motor and speech activity, uplifts mood, and reduces fatigue. Step 4: Therefore, all of the above statements are true, making option D the correct choice. Option A is correct as it highlights the CNS stimulant effects. Option B is incorrect as amphetamine does not directly stimulate the medullar respiratory center. Option C is also incorrect as it does not mention the full range of effects of amphetamine.

Correct Answer: B

Rationale: Step 1: Restlessness, anxiety, orthostatic hypotension, seizures, tremor, hallucination, and psychosis are symptoms commonly associated with withdrawal from a substance. Step 2: Withdrawal occurs when a person stops using a substance they have developed a physical dependence on. Step 3: Tolerance refers to the body's decreased response to a substance over time, not withdrawal symptoms. Step 4: Drug interactions between barbiturate and diazepam would not typically cause the wide range of symptoms mentioned. Step 5: Therefore, the correct answer is B (Withdrawal) as it aligns with the symptoms described.

Correct Answer: B

Rationale: Step-by-step rationale: 1. Sevoflurane is metabolized in the liver to release fluoride ions, which can lead to nephrotoxicity. 2. Fluoride ions can cause renal toxicity by forming calcium fluoride deposits in the renal tubules. 3. This can result in renal tubular dysfunction and acute kidney injury. 4. Halothane is hepatotoxic, not nephrotoxic. Nitrous oxide and diethyl ether do not cause nephrotoxicity. Summary: B: Sevoflurane is correct due to fluoride ion release causing nephrotoxicity. A, C, D are incorrect as they do not cause nephrotoxicity.