Which of the following can effect drug distribution inside the body?

Correct Answer: D

Rationale: Rationale: 1. Target site blood flow affects drug distribution by determining how quickly drug reaches the intended site. 2. Plasma protein binding affects distribution as only free drug is active and can reach target tissues. 3. Blood flow to the site of absorption impacts how rapidly drug is absorbed and distributed. 4. Option D is correct as both target site blood flow and blood flow to the site of absorption are crucial in drug distribution. Option A alone doesn't consider absorption, while option B focuses only on binding, neglecting absorption. Option C is specific to absorption and does not encompass target site blood flow.

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: B

Rationale: The correct answer is B because physiologic changes in older adults affect all pharmacokinetic processes, leading to increased risk for drug reactions. These changes include decreased renal function, altered drug metabolism, reduced liver enzyme activity, and changes in body composition. Option A is incorrect because the blood-brain barrier remains intact with age. Option C is incorrect as older adults have decreased drug-metabolizing enzymes. Option D is incorrect because while immune response may decline with age, it is not the primary factor contributing to increased drug reactions in older adults.

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.