ATI RN
Principles of Pharmacology Questions
Question 1 of 5
Which of the following was most likely the oral bioavailability of the drug?
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.
Question 2 of 5
A 17-year-old boy drank increasing amounts of alcohol when attending parties. He noticed that lately he was able to better tolerate alcohol effects and asked his physician the reason for this. The physician said that pharmacodynamic tolerance had probably occurred. Which of the following actions most likely mediated this tolerance?
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.
Question 3 of 5
A 22-year-old woman suffering from asthma was prescribed albuterol by inhalation. Albuterol is a bronchodilating drug with a molecular weight of 239 daltons. Which of the following permeation processes most likely accounted for the transfer of the drug through the bronchial mucosa?
Correct Answer: B
Rationale: Lipid diffusion is the most likely permeation process for the transfer of albuterol through the bronchial mucosa. Lipid-soluble molecules like albuterol can easily pass through the lipid bilayer of cell membranes. The other options are less likely mechanisms for the absorption of albuterol in this context.
Question 4 of 5
What is the main site of distribution of infliximab, a drug used to treat rheumatoid arthritis?
Correct Answer: A
Rationale: Failed to generate a rationale of 500+ characters after 5 retries.
Question 5 of 5
A new drug was tested in an in vitro system. It was found that only one enantiomer of the racemic pair bound substantially to a specific receptor, whereas the other enantiomer showed negligible binding. Which of the following terms best defines this property?
Correct Answer: C
Rationale: The correct answer is C. Stereoselectivity refers to the phenomenon where one enantiomer of a drug has a significantly higher binding affinity to a receptor compared to its mirror-image enantiomer. In this scenario, one enantiomer binds substantially while the other shows negligible binding, indicating stereoselectivity in receptor binding. This property is crucial in drug development as it can impact the efficacy and safety profile of a medication. Intrinsic activity (choice A) refers to the ability of a drug to activate a receptor once bound, while affinity (choice B) is the strength of binding between a drug and its receptor. Potency (choice D) refers to the dose of a drug required to produce a specific effect, and variability (choice E) is the degree of inconsistency in response to a drug.