Pharmacology Pharmacokinetics #4

Question

Which factor(s) would affect drug absorption of a liquid PO medication taken by a patient? Select all that apply.

Answers

  1. Glomerular filtration rate of the kidneys
    • Rationale:

      This is not the correct answer because glomerular filtration rate is associated with the excretion part of pharmacokinetics. Excretion is the removal of drugs from the body.

  2. Health and perfusion of the small intestines
    • Rationale:

      This is the correct answer because the health and perfusion of the small intestines is crucial for absorption for PO medications. Most PO medications are absorbed in the intestines. Adequate blood flow facilitates absorption of medication.

  3. Increased number of microvilli in the small intestines
    • Rationale:

      This is the correct answer because the increased number of microvilli in the small intestines increases surface area. The larger the surface area, the faster the medication will absorb. Most PO medications are absorbed in the small intestines rather than the stomach due to the large surface area compared to the stomach’s small surface area.

  4. Ability of the drug to dissolve after administration
    • Rationale:

      This is the correct answer because before a medication can be absorbed, it must dissolve. There is a direct correlation of the medication’s ability to dissolve to its rate of absorption. Liquid medications can absorb faster due to that fact.

  5. Capillary bed absorption rate in the deltoid muscle
    • Rationale:

      This is not the correct answer because the medication in the scenario is a liquid PO medication, not an intramuscular injection into the deltoid muscle. Capillary bed absorption rate does affect absorption but will not affect this particular PO medication.

Overview

Absorption is the movement of a medication from the site of administration into the blood. Absorption rates and what affects those is important to understand during medication administration.

Explanation

Learning Outcomes

Absorption is the movement of a medication from the site of administration into the blood. Many factors affect drug absorption, including health and perfusion of the site of administration, increased surface area, and the ability of the drug to dissolve after administration. The liquid form of a PO medication is affected by the health and blood flow of the small intestines because this helps facilitate the medication’s movement into the bloodstream. The increased number of microvilli in the small intestines increases the surface area, providing faster absorption of the drug. The ability of the drug to dissolve makes the drug absorb faster into the bloodstream. For example, the liquid form greatly increases the rate of absorption.

Test Taking Tip

Be sure you read the details of the question, including “liquid” oral medication since this could be a key point to consider when answering the question.

Video Rationale