Due to the impaired homeostatic mechanisms olderpeople have an increased susceptibility to drug induced side effects such as urinary incontinence, urine retention, confusional states, hypothermia and postural hypotension..
Due to the impaired homeostatic mechanisms olderpeople have an increased susceptibility to drug induced side effects such as urinary incontinence, urine retention, confusional states, hypothermia and postural hypotension..
Aside of these pharmacokinetic changes, one of the characteristics of old age is a progressive decline in counterregulatory (homeostatic) mechanisms.
Therefore drug effects are mitigated less, the reactions are usually stronger than in younger subjects, the rate and intensity of adverse effects are higher..
As you get older, body changes can affect the way medicines are absorbed and used.
For example, changes in the digestive system can affect how fast medicines enter the bloodstream.
Changes in body weight can influence the amount of medicine you need to take and how long it stays in your body..
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..
In general, as we age, total body water and muscle mass decrease while percentage of body fat increases.
These changes can lead to drugs having a longer duration of action and increased effect.
Drugs that were effective may become compounded and overexceed their therapeutic threshhold causing increased side effects..
Due to the impaired homeostatic mechanisms olderpeople have an increased susceptibility to drug induced side effects such as urinary incontinence, urine retention, confusional states, hypothermia and postural hypotension..
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..
Pharmacodynamics and pharmacokinetics are the two branches of pharmacology, with pharmacodynamics studying the action of the drug on the organism and pharmacokinetics studying the effect the organism has on the drug..
Age-related changes in pharmacokinetics principally affect drug absorption, distribution, metabolism and elimination.
Changes in pharmacodynamics are primarily seen in the cardiovascular and neuroendocrine system..
Ageing is associated with the change in the physiology of the body.
This altered physiology plays a vital role in changing drug pharmacokinetics and pharmacodynamics.
In some cases, the drug concentration will be reduced and requires a higher dose to compensate for the loss of the drug to show its therapeutic efficacy..
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..
This review article summarizes the most clinically relevant changes in human organ and body functions and the consequential pharmacokinetics and pharmacodynamics in older people, along with possible dosing consequences or alternatives for drugs frequently prescribed to this patient population.
Multiple theories have been proposed for explaining age-related pharmacodynamic alterations.
It is believed that initial exposure of the dihydropyridines to the baroreceptors reduces the response to low blood pressure, and over time, it corrects itself upon prolonged drug exposure.
In addition, aging affects the pharmacological response of many drugs by changing the pharmacodynamics of the drugs.
The pharmacological response of the drugs majorly depends on the number of target receptors and affinity of the drug to the target (e.g., transporters, ion channels, enzymes, and receptors) ( Turnheim, 2003 ).
Pharmacokinetics is best defined as what the body does to the drug; it includes ,With aging, there are changes in all these areas; some changes are more clinically relevant.
The metabolism and excretion of many drugs decrease, requiring that doses of some drugs be decreased.
