4.2.3 Kinetic changes in health and disease

4.2.3 Kinetic changes in health and disease

Kinetic Changes in Health (e.g. pregnancy) and Disease and Across the Life Span

Health and disease can change over the course of a person’s life due to various physical, biological, and environmental factors. These changes can be particularly pronounced during different stages of the life span, such as childhood, adolescence, adulthood, and old age.

Pregnancy:

Pharmacokinetics, or the study of how drugs are absorbed, distributed, metabolized, and excreted in the body, can change during pregnancy. This can affect the safety and efficacy of medications used to treat various conditions during pregnancy. Some of the factors that can influence pharmacokinetics during pregnancy include:

  1. Hormonal changes: Hormonal fluctuations during pregnancy can alter drug metabolism and elimination, leading to changes in the pharmacokinetics of drugs.
  2. Increased blood volume: Pregnancy results in an increase in blood volume, which can affect the distribution of drugs in the body.
  3. Reduced gastric motility: Pregnancy can slow down the rate of gastric emptying, affecting the absorption of drugs.
  4. Changes in renal function: The kidneys play a key role in drug elimination, and changes in renal function during pregnancy can affect pharmacokinetics.
  5. Placental transfer: Some drugs can cross the placenta and affect the developing fetus, leading to changes in pharmacokinetics.

Due to these changes, it is important to carefully consider the use of medications during pregnancy and to seek medical advice before taking any new drugs during this period (Mitra, 2017).

Disease:

Pharmacokinetics can change during disease for various reasons, including alterations in the absorption, distribution, metabolism, and excretion of drugs. Some of the factors that can affect pharmacokinetics during disease include:

  1. Changes in body composition: Diseases such as obesity or malnutrition can alter body composition, affecting the distribution of drugs in the body.
  2. Alterations in organ function: Diseases that affect organs such as the liver, kidneys, or gut can alter drug metabolism and elimination, leading to changes in pharmacokinetics.
  3. Drug-drug interactions: Certain diseases can increase the risk of drug-drug interactions, leading to changes in pharmacokinetics.
  4. Chronic use of drugs: Chronic use of drugs, especially in diseases such as cancer or chronic pain, can lead to drug accumulation and changes in pharmacokinetics over time.
  5. Inflammation: Inflammation, which is a hallmark of many diseases, can alter drug metabolism and elimination, leading to changes in pharmacokinetics.

Therefore, it is important to consider the impact of disease on pharmacokinetics when prescribing medications and to closely monitor patients with underlying medical conditions for any changes in response to drugs. Regular reassessment of the pharmacokinetics of drugs in the presence of the disease may be necessary to ensure that they are being used safely and effectively (Liu, 2018).

References:

(1) Liu, J., & Callaghan, J. (2018). Alterations in pharmacokinetics in disease states. Clinical Pharmacokinetics, 57(11), 1267-1279. doi: 10.1007/s40262-018-0636-9

(2) Mitra, A. (2017). Drug disposition during pregnancy. Expert Opinion on Drug Metabolism & Toxicology, 13(7), 719-727. doi:10.1080/17425255.2017.1328397