The lithium mode of action is:

Correct Answer: D

Rationale: The correct answer is D: All of the above. Lithium has a multifaceted mode of action. 1. Lithium affects electrolytes and ion transport by altering sodium and potassium levels. 2. It influences neurotransmitters like serotonin and norepinephrine. 3. It also modulates second messenger systems like the inositol pathway. Therefore, choice D is correct as lithium impacts all these pathways. Choices A, B, and C are incorrect because they individually represent only a part of lithium's overall mode of action.

Correct Answer: C

Rationale: The correct answer is C: More than 800 mg/d. High doses of benzodiazepines increase the risk of developing physical dependence, leading to severe withdrawal symptoms when discontinued. Dosages exceeding 800 mg/d are considered very high and are more likely to result in severe withdrawal symptoms after prolonged use. Choices A, B, and D all suggest lower dosages which are less likely to cause severe withdrawal symptoms compared to doses exceeding 800 mg/d. Therefore, option C is the correct choice for the dosage of benzodiazepines that may produce severe withdrawal symptoms after 60-90 days of use.

Correct Answer: C

Rationale: The correct answer is C: Halothane. Halothane can produce hepatic necrosis due to its metabolite, trifluoroacetic acid. This metabolite can lead to liver damage in susceptible individuals. Other choices, A (Sevoflurane), B (Desflurane), and D (Nitrous oxide) do not typically cause hepatic necrosis. Sevoflurane and Desflurane are not metabolized to toxic compounds that affect the liver, and Nitrous oxide is not known to cause hepatic necrosis. Therefore, the correct answer is C because of the specific hepatotoxic effects associated with Halothane.

Correct Answer: A

Rationale: The correct answer is A: Sodium bicarbonate. Sodium bicarbonate causes metabolic alkalosis by increasing bicarbonate levels in the body, leading to an excess of base. This can occur in conditions like overdose or prolonged use. B: Cimetidine is an H2 receptor antagonist that can cause metabolic acidosis, not alkalosis. C: Pepto-Bismol contains bismuth subsalicylate and can cause metabolic acidosis. D: Carbenoxolone is a drug that can cause metabolic alkalosis.

Correct Answer: B

Rationale: The correct answer is B: FALSE. Urokinase is a thrombolytic agent that activates plasminogen to plasmin, which dissolves blood clots. It does not inhibit Thromboxane A2. Thromboxane A2 is involved in platelet aggregation and vasoconstriction. Choices A, C, and D are incorrect because urokinase does not inhibit Thromboxane A2.