lecture 4. geriatric Flashcards
(23 cards)
Age Affects Pharmacokinetic Processes
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. (ex. peristalsis slows down)
Physiological changes in the elderly
heart - cardiac output and blood flow decrease
liver - function of enzymes and blood flow decrease
kidneys - blood flow, glomerular filtration, and nephron function decrease
stomach - gastric secretions decrease
intestines - peristalsis and motility decrease; first pass effect decrease
*THEY ALL DECREASE - don’t always try to memorize, think about it logically!!
Pharmacokinetic Changes: absorption
slower gastric emptying, altered nutritional habits, greater use of OTC medications.
Distribution
increased body fat, reduced lean body mass, reduced total body water (seniors don’t want to drink and go pee as often)
Metabolism
heart failure and diseases that affect liver function more common.
Elimination
decreased cardiac output and blood flow affect liver and kidneys.
Creatinine clearance is an indicator of glomerular filtration rate.
Liver and kidney dysfunction may cause intensified drug effects because of increased half-life.
Pharmacokinetic changes
SEE CHART for all detailed numbers!!!
body fat INCREASES
body water, hepatic blood flow, kidnet weight, lean body mass, serum albumin ALL DECREASE
Pharmacodynamic Changes
Changes in CNS may cause more or less sensitivity to drug action due to changes in receptors.
Average blood pressure and symptomatic orthostatic hypotension (low blood pressure that happens when standing after sitting or lying down) increase with age.
Blood glucose levels often increase, and temperature regulation is sometimes impaired.
Yohimbe
Yohimbe is a natural supplement widely taken to treat ERECTILE DYSFUNCTION
It is not standardized because it is a supplement
Patients with any of the following should NOT take yohimbe:
- Hypertension
- Hepatic disease (liver)
- Renal disease (kidney)
- Peptic ulcer (stomach/ upper small GI)
Polypharmacy
Multiple drug therapies cause confusion in elderly patients and lead to medication errors and further drug interactions.
- Increase risk of toxicity.
- Increases risk of drug-drug, drug-nutrient and drug-disease interactions.
- Increases risk of mistakes in taking their medication.
- Increases chances of liver dysfunction, malnutrition, confusion, and falls.
(Liver can regenerate!)
- Liver dysfunction contributes to delirium and acute confusional states.
Changes in Drug Effects (for geriatric patients) Antihypertensives
may cause hyperglycemia (blood sugar), hyperuricemia (urine), hypokalemia (potassium)
Changes in Drug Effects (for geriatric patients) Cardiac glycosides
Possible toxic effects more dangerous
Half-life of digoxin may be increased by 50%, narrow therapeutic range (must be careful with narrow therapeutic ranges).
Toxic effects are more dangerous, it takes longer for the body to clear digoxin, so it stays in the system longer than normal, and the safe amount of digoxin in the blood is very small
Changes in Drug Effects (for geriatric patients) Antiarrhythmic drugs
chance of toxicity increases.
Changes in Drug Effects (for geriatric patients) Anticoagulants
increased risk of bleeding.
Changes in Drug Effects (for geriatric patients) Sedatives/hypnotics:
eliminated more slowly if patients have reduced renal function.
Changes in Drug Effects (for geriatric patients) Narcotic analgesics:
elderly patients more susceptible to RESPIRATORY effects.
Changes in Drug Effects (for geriatric patients) Antidepressants/antipsychotics
Older antipsychotic drugs should be avoided in elderly patients; older adults more likely to experience toxic effects of antidepressants.
NSAIDs (nonsteroidal anti-inflammatory drugs):
must be used cautiously.
Advil, Ibuprofen, naproxen, etc..
Corticosteroids
may cause osteoporosis.
Increased laxative use
may cause electrolyte imbalances.
Aminoglycosides (type of abx)
toxic to kidneys and other organs; other antimicrobial drug doses should be reduced in patients with renal dysfunction.
Noncompliance
Noncompliance with prescribed drug therapy due to forgetfulness, adverse effects, confusion, physical disabilities, inability to read directions (visual problems), lack of understanding of health issues.
Inadequate health-care and prescription coverage often forces older patients to avoid taking required medications.
Socioeconomic factors also need consideration.
Drug Prescriptions in Elderly Population
People OLDER THAN 65 account for MORE THAN 32% of the drugs prescribed in the United States, even though they REPRESENT ONLY about 12% of the total population
