How does pharmacokinetics change in the elderly?
Table of Contents
How does pharmacokinetics change in the elderly?
One of the most important pharmacokinetic changes associated with aging is decreased renal elimination of drugs. After age 40, glomerular filtration rate (GFR) decreases an average of 8 mL/min/1.73 m2/decade (0.1 mL/sec/m2/decade); however, the age-related decrease varies substantially from person to person.
How is drug distribution affected by age?
As age increases, the functions of tissues and organs in the body gradually decline. Due to this decline in organ function, drug absorption, distribution, metabolism and excretion (ADME processes) in elderly people are worse than those of young people.
What factors can affect drug metabolism in an elderly?
Aging results in a number of significant changes in the human liver including reductions in liver blood flow, size, drug-metabolizing enzyme content, and pseudocapillarization. Drug metabolism is also influenced by comorbid disease, frailty, concomitant medicines, and (epi)genetics.
How does age impact the pharmacokinetics of chronically administered medicines in geriatric patients?
Usually, age does not greatly affect clearance of drugs that are metabolized by conjugation and glucuronidation (phase II reactions). First-pass metabolism (metabolism, typically hepatic, that occurs before a drug reaches systemic circulation) is also affected by aging, decreasing by about 1%/year after age 40.
What are the pharmacodynamic changes in the elderly?
The most important pharmacodynamic differences with age for cardiovascular agents are the decrease in effect for beta-adrenergic agents. This decline in response in vascular, cardiac, and pulmonary tissue may be due to a decrease in Gs protein interactions.
What is the primary cause of slower absorption of oral medications in an elderly person?
Incomplete absorption of orally administered drugs occurs mainly because of lack of absorption from the gut. If a drug is too hydrophilic (easily absorbed by or dissolved in water) it will have trouble crossing the cell’s lipid membrane.
What are the effects of aging on pharmacokinetics and pharmacodynamics?
Ageing is associated with a reduction in first-pass metabolism. This is probably due to a reduction in liver mass and blood flow [52]. As a result, the bioavailability of drugs undergoing extensive first-pass metabolism such as propranolol and labetalol can be significantly increased [53–55].
How does old age affect drug absorption?
In the elderly there is a reduction in gastric pH which, in the case of some drugs, affects the solubility and thus will influence the rate of absorption. Furthermore, there is a reduction in intestinal blood flow, which would tend to delay or reduce drug absorption.
Why is drug absorption slower in older adults?
What causes the rate of absorption of a medication to be affected in the elderly?
How does aging affect the pharmacodynamics?
Which of the following physiological changes in geriatric patients affect drug distribution?
With age, body fat generally increases and total body water decreases. Increased fat increases the volume of distribution for highly lipophilic drugs (eg, diazepam, chlordiazepoxide) and may meaningfully increase their elimination half-lives.
Which physiological changes affect drug metabolism in the older adult quizlet?
Pharmacokinetics: How is metabolism affected by age? Reasons are reduced hepatic blood flow, reduced liver mass, and decreased activity of some hepatic enzymes. Liver function is diminished, half-lives of certain drugs may be increased, prolonging responses.
Which changes occur in the absorption process because of aging in elderly patients?
Absorption. Numerous gastrointestinal changes occur with age, e.g. increased gastric pH, delayed gastric emptying, decreased intestinal motility and decreased splanchnic blood flow, but surprisingly drug absorption changes very little [3].
How does aging affect pharmacodynamics?
What factors might impact patients pharmacokinetics and pharmacodynamics?
Pharmacokinetics can vary from person to person and it is affected by age, gender, diet, environment, body weight and pregnancy, patient’s pathophysiology, genetics and drug- drug or food-drug interactions. Drug therapy is impacted by factors that affect pharmacokinetics and pharmacodynamics.
How does aging affect drug absorption metabolism distribution and excretion?
In general drug absorption, distribution in the body, activity, metabolism and excretion can all change as a result of ageing. The older person is more likely to experience side effects as well as experiencing difficulty in swallowing their medication.
How do you explain pharmacokinetics to a patient?
Pharmacokinetics is currently defined as the study of the time course of drug absorption, distribution, metabo- lism, and excretion. Clinical pharmacokinetics is the application of pharmacokinetic principles to the safe and effective therapeutic management of drugs in an individual patient.
