Which site of drug absorption is considered to have the largest surface area?

Correct Answer: D

Rationale: The correct answer is D: Lungs. Lungs have the largest surface area for drug absorption due to alveoli and extensive capillary network. The large surface area allows for rapid absorption of drugs into the bloodstream. Rectum, vagina, and eye have smaller surface areas and are not as efficient for drug absorption compared to the lungs. Lungs provide a direct route to the bloodstream, making them an ideal site for drug absorption.

Correct Answer: D

Rationale: The correct answer is D because mannitol is an osmotic diuretic that increases the osmolarity of plasma. This high osmolarity creates an osmotic pressure gradient that pulls water out of the tissues into the bloodstream, leading to increased urine production. Choice A is incorrect because mannitol does not compete with aldosterone for cellular receptor sites. Choice B is incorrect because mannitol primarily works in the proximal tubule, not the loop of Henle. Choice C is incorrect because mannitol does not interfere with the absorption of sodium ions across the distal renal tubule.

Correct Answer: A

Rationale: The correct answer is A because the half-life of naloxone is relatively short, typically around 30-81 minutes. This short half-life means that the effects of naloxone wear off quickly, necessitating repeated doses to maintain its therapeutic effects in reversing opioid overdose. Choice B is incorrect because an increase in dosage is not necessarily required due to the short half-life of naloxone. Choice C is incorrect because as long as naloxone is still effective in reversing opioid overdose, there is no need for a different antidote solely based on the decreasing serum levels of naloxone. Choice D is incorrect because naloxone is an effective antidote for opioid overdose when administered correctly, despite its short half-life.

Correct Answer: A

Rationale: The correct answer is A: Intravenous. In cardiovascular collapse, immediate action is crucial. Intravenous administration ensures rapid delivery of medications directly into the bloodstream, achieving quick onset of action. Oral route is too slow, rectal route may be unreliable, and topical route is not suitable for immediate systemic effects. Intravenous route is the most appropriate in this critical situation.

Correct Answer: C

Rationale: The correct answer is C because drugs with a significant first-pass effect are extensively metabolized by the liver upon oral administration, leading to reduced bioavailability and potentially minimal therapeutic effects. This is due to the high enzymatic activity in the liver that rapidly breaks down the drug before it reaches the systemic circulation. Choices A, B, and D are incorrect because drugs with a significant first-pass effect are not limited to oral administration only, do not bypass hepatic circulation, and are not necessarily converted to more active and fat-soluble forms by the liver.