Half-life of cyclosporine A is:

Correct Answer: D

Rationale: The correct answer is D: 19 hours. The half-life of a drug is the time it takes for the concentration of the drug in the body to reduce by half. Cyclosporine A has a half-life of approximately 19 hours, meaning that it takes 19 hours for the concentration of cyclosporine A in the body to decrease by half. This is the most accurate description of the half-life of cyclosporine A. Choice A (25-35 minutes) is too short for the half-life of cyclosporine A, as it typically stays in the body for a longer duration. Choice B (21 days) is too long for the half-life of cyclosporine A, as this is more commonly seen in drugs with very long half-lives. Choice C (4 - 16 hours) is closer to the correct answer, but 19 hours is a more precise estimate for the half-life of cyclospor

Correct Answer: B

Rationale: Correct Answer: B Rationale: 1. Nicotinic acid (Niacin) primarily works by inhibiting lipolysis in adipose tissue, leading to decreased free fatty acids and triglycerides. 2. Triglycerides and LDL cholesterol are reduced by Niacin due to its effect on lipid metabolism. 3. High doses of Niacin can indeed cause hepatic or pancreatic disturbances, leading to the discontinuation of doses higher than 3 gm/day. 4. Cutaneous flushing and itching are common side effects of Niacin, not directly related to the drug's effect on apoproteins synthesis.

Correct Answer: A

Rationale: Step 1: 25-hydroxyvitamin D3 (calcifediol) is a precursor to 1,25-dihydroxyvitamin D3 (calcitriol). Step 2: Calcitriol is the active form of vitamin D that stimulates intestinal calcium transport. Step 3: Calcifediol is converted into calcitriol in the kidneys. Step 4: Since calcifediol is less potent than calcitriol, it is less effective in stimulating intestinal calcium transport. Step 5: Therefore, hypercalcemia, a condition of high calcium levels in the blood, is less likely to occur with calcifediol compared to calcitriol. Summary: Choice A is correct because calcifediol is indeed less effective than calcitriol in stimulating intestinal calcium transport, leading to a lower risk of hypercalcemia. Choices B, C, and D are incorrect as they do not accurately reflect the relationship between

Correct Answer: A

Rationale: The correct answer is A: Intravenous. Plicamycin is a cytotoxic antibiotic that is administered intravenously to ensure direct delivery into the bloodstream for optimal absorption and distribution to target tissues. Subcutaneous and intranasal routes are not suitable for plicamycin due to its potency and potential irritation at the injection site. Oral administration is ineffective as plicamycin is poorly absorbed through the gastrointestinal tract and extensive first-pass metabolism would render it ineffective. Therefore, intravenous administration is the most appropriate route for plicamycin to achieve desired therapeutic effects.

Correct Answer: C

Rationale: The correct answer is C: Co-trimoxazole. Co-trimoxazole is a combination of sulfamethoxazole and trimethoprim, which are not antibiotics but rather antimicrobial agents. Streptomycin, Penicillin, and Chloramphenicol are all antibiotics that target and kill bacteria. Antibiotics specifically target bacterial infections, while antimicrobial agents can target a broader range of microbes. Therefore, Co-trimoxazole does not fall under the category of antibiotics, making it the correct answer.