Diarrhea and other lower intestinal fluid losses will contribute to:

Choice A Reason:

To determine how much of the medication remains in the body after a certain period, we need to understand the concept of half-life. The half-life of a medication is the time it takes for the concentration of the drug in the bloodstream to reduce by half. For Medication A, the half-life is 3 hours. After 12 hours, which is four half-lives, the amount of medication remaining can be calculated step by step.

Choice B Reason:

Let’s break down the calculation. Initially, the patient receives 400 mg of Medication A. After the first half-life (3 hours), the amount of medication remaining is 400 mg ÷ 2 = 200 mg. After the second half-life (6 hours), the amount remaining is 200 mg ÷ 2 = 100 mg. After the third half-life (9 hours), the amount remaining is 100 mg ÷ 2 = 50 mg. Finally, after the fourth half-life (12 hours), the amount remaining is 50 mg ÷ 2 = 25 mg. Therefore, 375 mg is not a correct answer.

Choice C Reason:

Similarly, 150 mg is not correct. As shown in the detailed calculation, the amount of medication decreases by half every 3 hours. After 12 hours, the remaining amount is 25 mg, not 150 mg. This choice does not align with the half-life calculation.

Choice D Reason:

This is the correct answer. The step-by-step calculation shows that after 12 hours, which is equivalent to four half-lives, the amount of Medication A remaining in the patient’s body is 25 mg. This demonstrates the principle of half-life and how the concentration of a drug decreases over time.

Choice A Reason:

Biotransformation, also known as drug metabolism, is the process by which the body chemically alters a drug. This typically occurs in the liver and results in the conversion of the drug into metabolites, which can be more easily excreted from the body. Biotransformation is crucial for drug elimination but is not the process by which a drug is transported to receptor sites.

Choice B Reason:

Distribution is the correct answer. This process involves the dispersion of a drug throughout the body via the bloodstream after it has been absorbed. The drug is transported to various tissues and organs, including the target receptor sites where it exerts its therapeutic effects. Distribution is influenced by factors such as blood flow, tissue permeability, and the binding of the drug to plasma proteins.

Choice C Reason:

Osmosis is the movement of water molecules across a semipermeable membrane from an area of lower solute concentration to an area of higher solute concentration. While osmosis is a fundamental biological process, it is not involved in the transport of drugs to receptor sites.

Choice D Reason:

Absorption is the process by which a drug enters the bloodstream from its site of administration. This can occur through various routes, such as oral, intravenous, or transdermal. Absorption is the initial step in drug delivery, but it is not the process by which the drug is transported to receptor sites.