Which of the following drugs most likely has the highest oral bioavailability?

Correct Answer: B

Rationale: In pharmacology, bioavailability refers to the proportion of a drug that reaches systemic circulation following administration. The correct answer, Drug Q, likely has the highest oral bioavailability among the options due to its specific pharmacokinetic properties. Drug Q might have a higher oral bioavailability because of factors such as better absorption, minimal first-pass metabolism, or formulation enhancements that improve its uptake in the gastrointestinal tract. This could lead to a higher concentration of the drug in the bloodstream after oral administration compared to the other options. Conversely, Drugs P, R, and S may have lower oral bioavailability for various reasons. Drug P might have poor absorption, Drug R could undergo significant first-pass metabolism reducing its systemic availability, and Drug S might have formulation issues that hinder its absorption. Educationally, understanding factors influencing oral bioavailability is crucial for pharmacology students and healthcare professionals to optimize drug therapy outcomes. It highlights the importance of drug formulation, pharmacokinetics, and patient-specific factors in drug selection and dosing. Remembering these principles aids in selecting appropriate medications for patients based on their individual needs and characteristics.

Correct Answer: D

Rationale: The injected dose of cocaine can be calculated using the formula Dose = Cp * Vd, where Cp is the plasma concentration, and Vd is the volume of distribution. Given that the plasma level of cocaine was 0.75 mg/L, and the volume of distribution is about 130 L, the injected dose can be calculated as 0.75 * 130 = 97.5 mg, which is closest to option D.

Correct Answer: A

Rationale: In this question, the correct answer is option A) Drugs P and Q. The rationale behind this is that drugs P and Q can fully activate the same receptors. This means that both drugs bind to the receptors and produce a maximal response. This is a key concept in pharmacology where drugs that fully activate the same receptors are considered to have similar pharmacological effects. Now, let's analyze why the other options are incorrect: - Option B) Drugs P and R: These drugs do not fully activate the same receptors, so they would not be the correct pair. - Option C) Drugs P and S: Similarly, these drugs do not fully activate the same receptors, making this option incorrect. - Option D) Drugs Q and T: These drugs also do not fully activate the same receptors, so they are not the correct pair. From an educational standpoint, understanding drug-receptor interactions is fundamental in pharmacology. Knowing which drugs can fully activate the same receptors is crucial in predicting their effects and potential interactions. This question tests students' knowledge of receptor activation and its implications in drug actions, highlighting the importance of specificity in pharmacological responses.

Correct Answer: B

Rationale: In this scenario, the correct answer is B) Partial agonist. A partial agonist is a drug that binds to a receptor and produces a response, but the response is less than that of a full agonist. In the context of the question, drug X is not a full agonist because it can be antagonized by drug Z, indicating that it does not fully activate the receptor. Competitive antagonist (option A) competes with the agonist for the same binding site on the receptor, but since drug Z antagonized drug X, it suggests that drug Z and X do not compete for the same binding site. Inverse agonist (option C) produces effects opposite to those of an agonist by reducing the basal activity of a receptor, which is not the case with drug X in this scenario. Irreversible antagonist (option D) permanently binds to the receptor, rendering it inactive, which is not the situation described in the question. Understanding the concept of partial agonists is crucial in pharmacology as it helps in comprehending how different drugs interact with receptors, leading to varied physiological responses. It also highlights the importance of drug-receptor interactions in pharmacotherapy and drug development.

Correct Answer: B

Rationale: The correct answer is B (5%) because the question is asking for the bound percentage of atenolol after a specific dose has been administered. Since the dose is 50 mg/d, the correct answer can be calculated as 50 mg/d / 1000 mg/g x 0.10 (10%) = 5%. This calculation shows that 5% of the atenolol would be bound.