DRUG USE AND PRINCIPLES OF CLINICAL CARE IN GERIATRIC PATIENTS
DRUG USE AND PRINCIPLES OF CLINICAL CARE IN GERIATRIC PATIENTS
Geriatrics and Gerontology are often used to mean the same thing. Geriatrics is the branch of medicine that deals with the illness and care of the aged, while Gerontology is the study of factors affecting the normal aging process and the effects of aging on persons of all ages.
Geriatric nursing focuses on the care of the sick elderly. Gerontologic nursing includes not only the care of the sick elderly, but also health maintenance, illness prevention, and the promotion of quality of life to assist the person to grow to an ideal state of health and well being.
Simply stated, our role as health care providers is to assist our elderly patients to get better, to maintain at their current status – accepting declines – or to ease their dying.
Pharmacotherapy for the elderly can cure or palliate disease as well as enhance health-related quality of life (HRQOL). HRQOL considerations for the elderly include focusing on improvement in physical functioning, psychological functioning, social functioning, and overall health. Despite the benefits of pharmacotherapy, HRQOL can be compromised by drug-related problems. The avoidance of drug related adverse consequences in the elderly requires health care practitioners to become knowledgeable about a number of age-specific issues.
GERIATRIC PHARMACOLOGY
In general, everything diminishes with age. Both the pharmacodynamic as well as the pharmacokinetic character changes with time. With aging inherent variability in physiologic differences becomes accentuated. Pharmacodynamic responses are blunted, ability to eliminate drugs is diminished and sensitivity to the toxic effects of drugs is increased. The effects of diseases are often additive and accumulate with time. Disability and capacity for recuperation or compensation are decreased. As a result the incidence of adverse drug events is concentrated in the elderly.
The concern for drug use in the elderly stems from the disproportionate use of drugs in the elderly. Geriatric patients represent 12% of population but receive 30% of all prescriptions. Two thirds use 1 or more drugs daily. Average use is 5 – 12 drugs daily and < 5% use no drugs. One third use 1 or more psychotropic drugs each year.
PATHOPHYSIOLOGY OF AGING
In the elderly the physiologic underpinnings are altered. There is an altered, usually diminished, receptor sensitivity and responsiveness. The ability to mount a compensatory physiologic response is diminished. Normal homeostatic mechanisms are blunted and sometimes produce inappropriate responses.
The elderly accumulate diseases. Even “healthy” elderly have diminished capacities. Aging is a continuum and the aged are stratified by degree of age. As age progresses so do the exceptional considerations.
ALTERED PHARMACOKINETICS
ABSORPTION –
Age related changes are small. Decreased motility and changes in surface area are less significant than disease-specific changes. Effects of age on absorption for delayed and sustained release formulations have not been well-documented. A diminished first-pass effect results in an increased bioavailability.
DISTRIBUTION-
As a consequence of the age-related changes in body composition, polar drugs that are mainly water-soluble tend to have smaller volumes of distribution (V) resulting in higher serum levels in older people. Gentamicin, digoxin, ethanol, theophylline, and cimetidine fall into this category. Loading doses of digoxin need to be reduced to accommodate these changes. On the other hand, nonpolar compounds tend to be lipid-soluble and so their V increases with age. The main effect of the increased V is a prolongation of half-life. Increased V and t1/2 have been observed for drugs such as diazepam, thiopentone, lignocaine, and chlormethiazole.
METABOLISM-
In general, oxidative capacity is somewhat diminished with age. Phase II reactions are better preserved than Phase I. Disease and environmental factors have a greater impact on hepatic drug metabolism than age per se. High extraction drugs may have decreased clearance.
ELIMINATION –
Decrease in Clearance and increase in half- life for renally cleared drugs.
The age-related change in renal clearance is the most consistent and predictable change in pharmacokinetics. The dose of most drugs that are renally cleared should be adjusted for renal function. The adjustment method most frequently used is the Cockroft-Gault equation to estimate renal clearance.
CLCr (ml/min) =
(140 – age) (lean weight in kg)
72 (serum creatinine in mg/dL)
ALTERED PHARMACODYNAMICS
There is some evidence in the elderly of altered drug response or “sensitivity.” Four possible mechanisms have been suggested: (1) changes in receptor numbers, (2) changes in receptor affinity, (3) postreceptor alterations, and 4) age-related impairment of homeostatic mechanisms. For example, muscarinic, parathyroid hormone, ?-adrenergic, ?1-adrenergic, and ?-opioid receptors exhibit reduced density with increasing age. Also, the elderly are more sensitive to the central nervous system effects of benzodiazepines. The elderly also exhibit a greater analgesic responsiveness to opioids when compared with their younger counterparts, even when pharmacokinetic parameters are similar in the two groups. In addition, the elderly demonstrate an enhanced responsiveness to anticoagulants such as warfarin and heparin, as well as thrombolytic therapy. In contrast, the elderly exhibit decreased responsiveness to certain drugs (e.g., ?-agonists/antagonists). Also, reflex tachycardia, seen commonly with vasodilator therapy, is often blunted in the elderly. For some drugs (e.g., calcium channel blockers), both enhanced responsiveness (as demonstrated by greater reduction in blood pressure) and decreased responsiveness (as demonstrated by reduced atrioventricular nodal blockade) can occur simultaneously in elders.
Physiologic Changes with Aging
Organ System Manifestation
Body composition
? Total body water
? Lean body mass
? Body fat
? or ? Serum albumin
? or ? ?1-Acid glycoprotein (? by several disease states)
Cardiovascular
? Myocardial sensitivity to beta-adrenergic stimulation
? Baroreceptor activity
? Cardiac output
? Total peripheral resistance
Central nervous system
? Weight and volume of the brain
Alterations in several aspects of cognition
Endocrine
Thyroid gland atrophies with age
Increase in incidence of diabetes mellitus, thyroid disease
Menopause
Gastrointestinal
? Gastric pH
? Gastrointestinal blood flow
Delayed gastric emptying
Slowed intestinal transit
Genitourinary
Atrophy of the vagina due to decreased estrogen
Prostatic hypertrophy due to androgenic hormonal changes
Age-related changes may predispose to incontinence
Immune
? Cell-mediated immunity
Liver
? Liver size
? Liver blood flow
Oral
Altered dentition
? Ability to taste sweetness, sourness, and bitterness
Pulmonary
? Respiratory muscle strength
? Chest wall compliance
? Total alveolar surface
? Vital capacity
? Maximal breathing capacity
Renal
? Glomerular filtration rate
? Renal blood flow
? Filtration fraction
? Tubular secretory function
? Renal mass
Sensory
? Accommodation of the lens of the eye, causing farsightedness
Presbycusis (loss of auditory acuity)
? Conduction velocity
Skeletal
Loss of skeletal bone mass (osteopenia)
Skin/hair
Skin dryness, wrinkling,
changes in pigmentation, epithelial thinning,
loss of dermal thickness
? Number of hair follicles
? Number of melanocytes in the hair bulbs
COMMON CLINICAL DISORDERS IN GERIATRICS
Dementia
Dementia is progressive deterioration in intellectual function and other cognitive skills, leading to a decline in the ability to perform activities of daily living. Diagnosis is by history and physical examination. Potentially reversible causes of cognitive impairment (e.g., drugs, delirium, depression) should be excluded. Treatment is with general measures and usually a cholinesterase inhibitors(donepezil, rivastigmine, galantamine), memantine, or both.
Parkinsonism
It is a relatively common disease of the elderly. Levodopa preparations should be used with caution and bromocriptine and other ergot derivatives should be avoided.
Hypertension
Hypertension is defined as systolic BP >= 140 mm Hg or diastolic BP >= 90 mm Hg. Isolated systolic hypertension, a common form of hypertension in the elderly, is defined as systolic BP >= 140 mm Hg and diastolic BP < 90 mm Hg. For most elderly patients, hypertension does not have a reversible cause and is asymptomatic. Evaluation should include detection of other cardiovascular risk factors and end-organ damage and a search for secondary causes when appropriate. Treatment is with lifestyle modifications and drugs, often starting with a thiazide-type diuretic.
Cardiac failure
Heart failure is common among persons >= 65 years. Its prevalence increases exponentially after age 70. Heart failure is now the most common diagnosis among hospitalized elderly patients. Treatment should be aimed at reducing symptoms, improving quality of life, and preventing acute exacerbations and hospitalization. Diuretics, ACE inhibitors, nitrates and digoxin are important for elderly.
Myocardial infarction
Clinically recognized or unrecognized MI occurs in 35% of elderly persons; 60% of hospitalizations due to acute MI occur in persons >= 65yrs. Unless contraindicated, aspirin (or if contraindicated, ticlopidine or clopidogrel) should be given. The role of glycoprotein IIb/IIIa inhibitors (e.g., tirofiban, abciximab) in the treatment of elderly patients with acute MI is under study.
Urinary incontinence
Eight to 34% of community-dwelling elderly persons suffer from urinary incontinence; rates are higher in women than in men, and urinary incontinence affects > 50% of elderly patients in hospitals and in nursing homes. The commonly used drugs for detrusor instability are oxybutynin and tolterodine.
Constipation
Constipation is more common in elderly persons–who report more straining and sensation of anal blockage–than in middle-aged persons. It can be treated in most elderly persons with dietary and behavioral changes and judicious use of laxatives and enemas.
Osteoporosis
Fractures resulting from minimal trauma result in significant morbidity and mortality in the elderly. These fragility fractures are related to underlying osteoporosis. Treatment of osteoporosis with bisphosphonate therapy has been shown to be effective in reducing fracture incidence and was largely underutilized in our study.
Arthritis
Osteoarthritis, gout, pseudogout, rheumatoid arthritis and septic arthritis are the important joint diseases in elderly.
DRUG RELATED PROBLEMS IN THE ELDERLY
Although medications used by the elderly can lead to improvement in HRQOL, negative outcomes owing to drug-related problems are considerable. Three important and potentially preventable negative outcomes owing to drug-related problems that can
occur in the elderly are adverse drug withdrawal events (ADWEs), which are clinically significant sets of symptoms or signs caused by the removal of a drug; therapeutic failure (inadequate or inappropriate drug therapy and not related to the natural progression of disease); and adverse drug reactions (ADRs), defined as a reaction that is noxious and unintended and which occurs at dosages normally used in humans for prophylaxis, diagnosis, or therapy.
A number of factors are believed to increase the risk of drug related problems in the elderly, including suboptimal prescribing (e.g., overuse of medications or polypharmacy, inappropriate use, and underuse), medication errors (both dispensing and administration problems), and patient medication nonadherence (both intentional and unintentional).
Overuse
Polypharmacy can be defined as either the concomitant use of multiple drugs or the administration of more medications than are indicated clinically. Multiple medication use has been strongly associated with ADRs. Polypharmacy is also problematic for elderly
patients because it may increase the risk of geriatric syndromes (e.g., falls, cognitive impairment), diminished functional status, and health care costs.
Inappropriate prescribing
Inappropriate prescribing can be defined as prescribing of medications outside the bounds of accepted medical standards.
Underuse
An important and increasingly recognized problem in elders is underuse, defined as the omission of drug therapy that is indicated forthe treatment or prevention of a disease or condition. Underuse may have an important relationship with negative health outcomes in the elderly, including functional disability, death, and health services use.
Medication Nonadherence
Medication nonadherence is a common problem in the elderly. Nonadherence is associated with increased health services use and adverse drug reactions.
Approach to medication prescribing
At the point of initial prescribing, it is important to avoid using medications that are potentially inappropriate in the elderly. When starting a new medication, the lowest
possible dose should be used and titrated slowly. A rule of thumb to help prevent potentially harmful iatrogenic illness is to initiate a medication at one-third to one-half of the manufacturer’s recommended dosage. Whenever possible, once-a-day dosing is preferred since complex dosing makes it difficult for patients to adhere to medications. Each medication should be matched with its diagnosis, and those without a clear indication should be eliminated. A medication should not be added to combat the side effects of another one. When multiple medications are used for one diagnosis, maximizing doses should be considered the number of medications. A time-limited prescription should be written and a team approach, involving the family, caregiver and pharmacist should be followed.
GERIATRIC CARE
Generally, elderly have a different perception of life and death. They tend to be more anxious about disabilities, as it may lead to loss of independence and a precursor of death. They do not want to be a burden to themselves or to the family or society. The central theme of geriatric care is “Care rather than Cure”. Geriatric care aims at achieving:
Maximum functional capacity
Independence and comfort
Minimum caregiver stress
Best forms of health care
Listening to their statements
Respecting them at all times
Providing regular medical examination
Screening for common diseases
Implementing preventive measures
Executing health promotional activities
Geriatric care principles
To improve the quality of life is more important than prolonging life
To honor the patient’s wishes while investigating and treating
To improve the general condition and nutritional status
To identify co morbid conditions and correct them before surgery
To explain the procedure, possible risks and complications of the proposed surgery
To get detailed informed consent in writing for all procedures
To initiate the treatment early
To consider alternative modalities of treatment instead of high-risk surgery
To modify the treatment regimen considering the ageing physiology
To take up proactive measures so as to prevent any iatrogenic complications
To assess the capabilities of the patient and the family or caregivers as it is essential to make a good and safe management plan
To provide continued, comprehensive, interdisciplinary team care.
Differences between general and geriatric principles
General Principles
Geriatric Principles
Aim: to cure the disease
Aim: to cure if possible /take care always
Investigation & diagnosis is important
Investigations as per the wishes and
convenience of elders
Curative / extensive surgery
Curative/ palliative surgery
Preserve life at any cost
Preserve functional capacity
Geriatric Assessment
A comprehensive multidimensional geriatric assessment is the first step in treating the geriatric patients. It is important to examine physiological, mental and emotional functions as well as socioeconomic and environmental factors. A systematic evaluation of the patient’s ability to perform the tasks associated with independent living should be done and recorded for problem detection and treatment.
History taking in elders
Spend time in getting a good history from the patient, the family members and/ or the care giver in a comfortable surroundings. If needed, ask leading questions to get the proper history.
Elicit past history (go through the previous medical records), treatment history, personal history and family history.
Record patient’s attitude and treatment preferences, availability of family and financial support.
Enquire thoroughly complete medication history, poly pharmacy, over the counter drugs and alternative medicines. Consult referring physician for more details, if required.
Sometimes the history may not be forthcoming and the physian has to rely on the history given by the caregivers, physical examination and investigations.
Physical examination
Provide a comfortable environment for the elderly and carry out complete clinical examination under good lighting. Sometimes it is necessary to postpone the examination according to the patient’s wishes. Examine the following and record the findings.
General examination for the presence of anemia, cyanosis, jaundice, lymphadenopathy, edema, nutritional disorder, decubitus, colour of skin, hydration, oral cavity (for hygiene, dryness, glossitis, presence of teeth or dentures) etc.,
Systemic examination for CNS, CVS, RS, and abdomen
Local examination for mass lesion, ulceration and malignancy. Detailed inspection, palpation, percussion and auscultation should be done.
Diagnosis
All efforts should be taken to arrive at the clinical diagnosis and confirmed by investigations Multiple pathological problems with multiple symptoms are common in elders and no single diagnosis is possible for all symptoms
Sometimes it may not be possible to arrive at a diagnosis due to patients ill health and unwillingness or it may not be necessary if the patient is terminally ill. In such cases the general measures are taken to keep the geriatric patient comfortable and free from pain.
Treatment
Always aim for complete cure of the disease
The geriatric patient has many modalities of treatment and surgical option is one
among them.
Alternatives to high-risk surgery and non-operative treatments should also be ex-
-plained, if and when the surgery is contemplated.
Consider the general condition and co- morbidities, diagnosis, natural course of
the disease, complications and prognosis.
Sometimes cure may not be possible due to various reasons, in such situations palliative and supportive measures should be undertaken To relieve symptoms like dyspnoea, dysphagia and pain
To ameliorate the ill effects of foul smelling discharge, fungating ulceration
To provide enteric route for nutrition
Always provide general supportive measures and care
STRATEGIES OF HEALTHY PRESCRIBING IN OLDER PATIENTS
The vision is that older people should participate to their fullest ability in decisions about their health and wellbeing and in family and community life. They are supported in this by co-ordinated and responsive health and disability support programmes.
The following eight objectives identify areas where change is essential if the vision is to be achieved.
1. Older people and their families are able to make well-informed choices about options for healthy living, health care and/or disability support needs.
2. Policy and service planning will support quality health and disability support programmes integrated around the needs of older people.
3. Funding and service delivery will promote timely access to quality integrated health and disability support services for older people, family and carers.
4. The health and disability support needs of older will be met by appropriate, integrated health care and disability support services.
5. Population-based health initiatives and programmes will promote health and wellbeing in older age.
6. Older people will have timely access to primary and community health services that proactively improve and maintain their health and functioning.
7. Admission to general hospital services will be integrated with any community-based care and support that an older person requires.
8. Older people with high and complex health and disability support needs will have access to flexible, timely and co-ordinated services and living options that take account of family and carer needs.
ROLE OF PHARMACIST IN GERIATRIC CARE
Pharmacists are committed to optimizing pharmaceutical therapies for each patient to improve outcomes and reduce costs. They are making significant contributions to the profession through specialized pharmaceutical care. Pharmacists, aided by a comprehensive system employing information technology and clinical “best practices ” work with physicians to identify patients at risk for a given disease state and ensure that optimal drug therapy is received and unnecessary healthcare expenditures are eliminated. Medications are probably the single most important healthcare technology in preventing illness, disability and health in the geriatric population. New products provide pharmacists with valuable tools for promoting quality of life but also confer upon them the more difficult task as well as the greater responsibility of balancing clinical effects to provide the highest possible quality of life for their patients.
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