Chapter 10: Drug Therapy in Geriatric Patients Flashcards
Older adult pt
Disproportionately high prescription drug use exists in the older adult population
Older adult patients experience more adverse drug reactions and drug-drug interactions than younger patients do
~ 15% of poplation take 1/3 of all prescribed meds
Altered pharmacokinetics -More sensitive to drugs than younger adults and with greater variation in pharmacokinetics
Multiple and severe illnesses -Severity of illness, multiple pathologies
Multiple-drug therapy
Excessive prescribing
Poor adherence
a lot of this is secondary to organ system degeneration
Individualization of treatment is essential
Each patient must be monitored for desired and adverse responses
Regimen must be adhered to
Goals of treatment: Reduce symptoms and improve quality of life
outline of drug therapy in older adult pt
Pharmacokinetic changes in older adults
Pharmacodynamic changes in older adults
Adverse drug reactions and drug interactions
Promoting adherence
older adult absorption
Altered gastrointestinal absorption is not a major factor in drug sensitivity
Rate of absorption may slow with age
Delayed gastric emptying and reduced splanchnic blood flow also occur
distribution older adult
Increased percentage of body fat
Storage depot for lipid-soluble drugs
Decreased plasma levels
Decreased response
Decreased percentage of lean body mass
Decreased total body water
Distributed in smaller volume; concentration increased and effects more intense
Reduced concentration of serum albumin
May be significantly reduced in malnourished patients
Causes decreased protein binding of drugs and increased levels of free drugs
older adult metabolism
Hepatic metabolism declines with age
Reduced hepatic blood flow, reduced liver mass, and decreased activity of some hepatic enzymes occur
The half-lives of some drugs may increase, and responses are prolonged
Responses to oral drugs (e.g., those that undergo extensive first-pass effect) may be enhanced
Older adult excretion
Renal function undergoes progressive decline beginning in early adulthood -Reductions in renal blood flow, glomerular filtration rate, active tubular secretion, and number of nephrons
Drug accumulation as a result of reduced renal excretion is the most important cause of adverse drug reactions in older adults
Renal function should be assessed with drugs that are eliminated primarily by the kidneys
In patients who are older adults:
Use creatinine clearance rather than serum creatinine to assess this, because lean muscle mass (source of creatinine) declines in parallel with kidney function
Creatinine levels may be normal even though kidney function is greatly reduced
Pharm changes in older adult pt
Alterations in receptor properties may underlie altered sensitivity to some drugs
Drugs with more intense effects in older adults -Warfarin and certain central nervous system depressants
Beta blockers less effective in older adults, even in the same concentrations
Reduction in number of beta receptors
Reduction in the affinity of beta receptors for beta-receptor blocking agents
ADRs
Seven times more likely in the elderly
Account for 16% of hospital admissions
Account for 50% of all medication-related deaths
Majority are dose related rather than idiosyncratic
STOPP -screening tool of older peoples potentially inappro. Prescriptions
Symptoms in older adults often nonspecific
May include dizziness and cognitive impairment
Predisposing ADR factors
Drug accumulation secondary to reduced renal function
Polypharmacy
Greater severity of illness
Multiple pathologies
Greater use of drugs that have a low therapeutic index (e.g., digoxin)
Increased individual variations secondary to altered pharmacokinetics
Inadequate supervision of long-term therapy
Poor patient adherence
Measures to reduce ADRs
Obtain a thorough drug history that includes over-the-counter medications
Consider pharmacokinetic and pharmacodynamic changes due to age
Monitor the patient’s clinical response and plasma drug levels
Use the simplest regimen possible
Monitor for drug-drug interactions
Periodically review the need for continued drug therapy
Encourage the patient to dispose of old medications
Take steps to promote adherence and to avoid drugs on the Beers list
Promo dherence in cass with unintentiona nonadherence
Simplified drug regimens
Clear and concise verbal and written instructions
Appropriate dosage form
Clearly labeled and easy-to-open containers
Daily reminders
Support system
Frequent monitoring
Encourage pt to bing all pills to visits
26-59% of older adults fail to take meds as prescribed
Inentional nonadherence
Most cases (75%) of nonadherence are intentional
Reasons include the following:
High cost of drugs, side effects, and the patient’s belief that the drug is unnecessary or that the dosage is too high
