A patient’s nutritional intake and lab work reflects hypoalbuminemia. This is critical to prescribing because:

Correct Answer: C

Rationale: Rationale for Correct Answer C: 1. Albumin is a major plasma protein that binds to drugs. 2. Hypoalbuminemia means less albumin is available to bind drugs. 3. Less albumin results in more free drug in the bloodstream. 4. Free drug is pharmacologically active and can generate effects. 5. Therefore, with less albumin, less free drug is available to generate an effect. Summary: A: Distribution of drugs may be affected by protein binding, not albumin levels. B: Solubility matching absorption sites is more related to drug formulation. D: Albumin-bound drugs are not readily excreted by the kidney; they are protected from filtration.

Correct Answer: C

Rationale: The correct answer is C: Onset of action. This is the point in time when the drug concentration reaches a level where the therapeutic effect begins to be observed. The onset of action signifies the start of the drug's intended effect on the body. The minimum adverse effect level (Choice A) refers to the lowest concentration at which side effects may occur, not the therapeutic effect. The peak of action (Choice B) is the point when the drug's effect is at its maximum, not necessarily the first sign of therapeutic effect. The therapeutic range (Choice D) is the range of drug concentrations that produce the desired therapeutic effect without causing significant side effects, but it does not specifically indicate the onset of therapeutic action.

Correct Answer: C

Rationale: The correct answer is C: Desensitization or down-regulation with continuous use. Receptor agonists continuously activate receptors, leading to desensitization or down-regulation where the receptors become less responsive or decrease in number. This occurs due to the body's attempt to maintain homeostasis in response to constant stimulation. Choices A and D are incorrect because receptor agonists do not typically bind irreversibly or exhibit an inverse relationship between drug concentration and action. Choice B is incorrect as up-regulation is usually observed in response to receptor antagonists, not agonists.

Correct Answer: B

Rationale: The correct answer is B because drugs administered via IV route enter the bloodstream directly, allowing for immediate distribution throughout the body. This rapid distribution leads to fast onset of action. Choice A is incorrect as lipid solubility is not a requirement for IV absorption. Choice C is incorrect because nonionized drugs are not necessarily easily absorbed via IV route. Choice D is incorrect as pinocytosis is not a mechanism for drug absorption via IV route.

Correct Answer: B

Rationale: The correct answer is B because the blood-brain barrier is designed to restrict the passage of many drugs into and out of brain cells, regulating the entry of substances to protect the brain from harmful agents. Explanation: 1. The blood-brain barrier is a specialized structure that tightly regulates the passage of substances from the bloodstream into the brain. 2. Many drugs, especially water-soluble and ionized ones (choice A), face difficulty crossing this barrier due to their properties. 3. The fetal-placental barrier (choice C) primarily protects the fetus from harmful substances but does not slow drug entry into brain cells. 4. Lipid-soluble drugs (choice D) can actually pass through these barriers easily due to their chemical properties, posing risks for pregnant women. In summary, choice B is correct as it accurately describes the role of the blood-brain barrier in controlling drug entry into brain cells, while the other choices present inaccurate statements regarding these distribution barriers.