A 45-year-old woman recently diagnosed with lupus erythematosus started a treatment with a synthetic steroid. Which of the following is the most likely time lapse expected between receptor activation and therapeutic response?

Correct Answer: D

Rationale: The most likely time lapse expected between receptor activation and therapeutic response in this scenario would be one or two hours. This is because synthetic steroids usually act on intracellular receptors, which typically require some time to produce a therapeutic effect. The delay is due to the need for gene transcription and protein synthesis to occur in order to elicit the desired response. Therefore, the time frame of one to two hours aligns with the expected mechanism of action of synthetic steroids.

Correct Answer: C

Rationale: In this case, option C, "The administration of the drug in aqueous solution," is the correct answer. Acetaminophen is a drug that is well absorbed in the gastrointestinal tract when taken orally. However, its absorption can be delayed if it is administered in a non-aqueous solution. This is because drugs in aqueous solutions are more readily dissolved and available for absorption through the gastrointestinal mucosa. Option A, "A moderate increase in intestinal peristalsis," would actually enhance absorption by promoting movement of the drug through the intestines. Option B, "The presence of strong pain," would not directly impact the oral absorption of acetaminophen. Option D, "A large volume of distribution of the drug," is related to the distribution of the drug within the body and would not affect its oral absorption. From an educational standpoint, understanding factors that can influence the absorption of drugs is crucial for healthcare providers to ensure optimal drug therapy outcomes for their patients. Proper drug administration techniques, including selecting appropriate formulations, can significantly impact the effectiveness of pharmacological treatments.

Correct Answer: D

Rationale: The oral bioavailability of a drug can be calculated using the formula F = AUC oral / AUC IV, where AUC is the area under the concentration-time curve. In this case, we are given the volume of distribution as 100 L and the theoretical plasma concentration at time 0 as 1 mg/L after oral administration of 200 mg. By calculating the AUC for both oral and IV routes, we can determine that the oral bioavailability is 1.0, which corresponds to option D.

Correct Answer: B

Rationale: In pharmacology, understanding dose-response curves is crucial for predicting drug effects. When a fixed dose of a competitive α antagonist is given concomitantly with an agonist, it will shift the dose-response curve to the right due to competitive inhibition. Option B is the correct choice because it represents a rightward shift in the dose-response curve, indicating competitive antagonism. This shift means higher doses of the agonist are needed to produce the same effect in the presence of the antagonist. Options A, C, and D can be eliminated because they do not show the characteristic rightward shift seen with competitive antagonists. Curve P (A) may indicate a non-competitive antagonist, while Curves R (C) and S (D) do not demonstrate any form of antagonism. Educationally, this question reinforces the concept of competitive antagonism and how it influences dose-response relationships. Understanding these principles is essential for predicting drug interactions and designing effective treatment regimens in clinical practice.

Correct Answer: B

Rationale: Pharmacodynamic tolerance refers to the body's ability to adapt to the effects of a drug, leading to decreased responsiveness. In this case, the boy's ability to better tolerate alcohol effects indicates a form of tolerance mediated by homeostatic adaptive changes that counteract the drug effect. This type of tolerance involves physiological adjustments to mitigate the impact of the drug, allowing the individual to withstand higher doses. Therefore, the correct answer is B.