Age-related changes in drug absorption

Definition

Age-related changes in drug absorption refer to the physiological alterations that affect how drugs are taken up by the body as individuals age. These changes can lead to variations in drug efficacy and safety, particularly impacting both pediatric and geriatric populations due to differences in gastrointestinal function, body composition, and metabolic processes.

5 Must Know Facts For Your Next Test

1. In infants and young children, gastric pH is higher, which can affect the solubility and absorption of drugs that rely on acidic environments.
2. Older adults often experience decreased gastric emptying and slowed intestinal motility, leading to altered absorption rates of certain medications.
3. Body composition changes with age can influence drug distribution; older adults may have a higher percentage of body fat and lower lean body mass, affecting lipophilic and hydrophilic drug behavior.
4. The presence of comorbidities in older adults can complicate drug absorption and bioavailability due to changes in organ function.
5. Factors such as diet, concurrent medications, and overall health status must be considered when evaluating age-related changes in drug absorption.

Review Questions

• How do physiological changes in infants and young children impact drug absorption?
  • Physiological changes in infants and young children, such as higher gastric pH levels and immature gastrointestinal motility, significantly affect drug absorption. The higher pH can enhance the solubility of basic drugs while reducing that of acidic drugs. Additionally, slower gastric emptying can delay the onset of drug action, making it critical to consider these factors when prescribing medications for pediatric patients.
• What role do age-related changes in body composition play in drug pharmacokinetics for older adults?
  • Age-related changes in body composition significantly impact pharmacokinetics for older adults. As people age, there is often an increase in body fat percentage and a decrease in lean body mass. This change affects the volume of distribution for lipophilic drugs, which may accumulate more in fat tissues, while hydrophilic drugs may have a reduced volume of distribution due to decreased total body water. These shifts necessitate careful dosing adjustments to ensure therapeutic effectiveness without toxicity.
• Evaluate the implications of altered drug absorption on clinical outcomes for both pediatric and geriatric populations.
  • Altered drug absorption in both pediatric and geriatric populations can lead to significant clinical implications. In children, variations in absorption can result in under-dosing or over-dosing due to differences in gastric pH and motility. For older adults, decreased absorption rates can lead to delayed therapeutic effects or increased side effects from inappropriate dosing. Understanding these age-related changes is essential for healthcare providers to optimize medication management strategies and improve patient outcomes across these vulnerable age groups.

Related terms

Bioavailability:

The proportion of a drug that enters the circulation when introduced into the body and is available for action.

Geriatric Pharmacology: The study of how medications affect older adults, focusing on the unique pharmacokinetic and pharmacodynamic changes that occur with aging.

Pediatric Pharmacology: The study of how medications affect children, taking into account their developmental physiology, which influences drug absorption, distribution, metabolism, and excretion.