Drugs in Elderly Flashcards
What are the pharmokinectic changes in elderly ?
Absorption: slower gastric emptying,
altered nutritional habits, greater use of
OTC medications
• Distribution: increased body fat, reduced
lean body mass, reduced total body water
• Metabolism: heart failure and diseases
that affect liver function more common
Age
• The efficiency of pharmacokinetic processes varies as we age. • In the very young and the very old, the many ways in which bodies handle drugs can be significantly different from that of young or middle-aged adults.
Age Affects Phamrkonic processes
What are the pharmokinetic changes ?
Elimination: decreased cardiac output and
blood flow affect liver and kidneys
• Creatinine clearance may not indicate
decline in renal function
• Liver and kidney dysfunction may cause
intensified drug effects because of
increased half-life
What are the physiological changes old peopel
Heart - cardiac output and blood flow decrease
Liver - Fcunton of enzyme and blood flow decrease
Kidneys - Blood flow , glomerul filtration , neuphron function decrease
Stomach- gastric secreation decrease
Instetines - first pass effect decrease /Peritsialsi and mitlity decrease
Polypharmacy
is defined as increase in the number of medications or the use of more medications than are medically necessary.
Multiple medications prescribed
• Increases chances of drug–drug
interactions
• Increases chances of liver dysfunction,
malnutrition, confusion, and falls
• Liver dysfunction contributes to delirium
and acute confusion states
Multiple drug therapies cause
confusion in elderly patients and lead
to medication errors and further
drug interactions.
Changes in Drug Effects
Antihypertensives: may cause hyperglycemia, hyperuricemia, hypokalemia – Beta-blockers less frequently prescribed – ACE inhibitors less useful except in diabetes and heart failure – Alpha1 -blockers, centrally acting alpha2 agonists less frequently used
Changes in Drug Effects (continued)
Cardiac glycosides: possible toxic effects more dangerous – Half-life of digoxin may be increased by 50% • Antiarrhythmic drugs: chance of toxicity increases • Anticoagulants: increase in change of bleeding
Prothrombin Time
Elderly patients who are taking anticoagulants must have periodic monitoring of prothrombin time (PT) or international normalized ratio (INR) to determine the level of anticoagulant in the blood and to regulate anticoagulant therapy.
Changes in Drug Effects (continued)
Sedatives/hypnotics: eliminated more slowly if patients
have reduced renal function
• Narcotic analgesics: elderly patients more susceptible
to respiratory effects
• Antidepressants/antipsychotics: older antipsychotic
drugs should be avoided in elderly patients; older adults
more likely to experience toxic effects of
antidepressants
Depress/Suci
The suicide rate among people older than age 65 is more than twice the national average, and psychiatric depression, a leading cause of suicide, is often undertreated in elderly patients.
Drug disposition in the elderly
Ability to handle drugs less well compared with younger adults – Absorption and distribution – Metabolism – Excretion
Drug effect in elderly
Drug effect in the elderly • Changes in sensitivity – increased in the case of CNS drugs – decreased in the case of autonomic drugs • Problems associated with loss of normal function
Noncompliance
Noncompliance with prescribed drug therapy due to forgetfulness, adverse effects, confusion, physical disabilities, inability to read directions (visual problems) • Inadequate health-care and prescription coverage often forces older patients to avoid taking required medications.
Guidelines for treatment of the
elderly
• Is the drug needed? • Appropriate formulation • Correct dose and mode of administration • Compliance • Length of treatment • When treatment should otherwise be stopped (monitoring)
