Presentation on theme: "DRUG PRESCRIBING FOR THE ELDERLY"— Presentation transcript:
1DRUG PRESCRIBING FOR THE ELDERLY بسم الله الرحمن الرحيمDRUG PRESCRIBING FOR THE ELDERLYAly A. Misha’l MD, FACPSenior consultant in Medicineand EndocrinologyAmman-Jordan
2Senility and frailty was described in the Glorious Qur’an in a sense of physical weakness and decline in capabilities, implying significant needs for care, sympathy and mercy.
3” .... وقد بلغت من الكبر عتياً“ “…. And I have grown quite decrepit from old age”The Glorious Qur’an, Chapter19: Verse 8
4” قال ربي إني وهن العظم مني.....“ “ O my lord! Infirm (Brittle) indeed are my bones …”The Glorious Qur’an, Chapter 19: Verse 4.
5” ومنكم من يردُّ إلى أرذل العمل لكي لا يعلم بعد علم شيئاً“ “Some of you are sent back to feeble age, so that they know nothing after what they have known”The Glorious Qur’an, Chapter 16: Verse 70
6Caring for sick elderly subjects, as part of medical practice, is an act of worship, human and religious duty, that the whole society (Ummah) will be held sinful if it fails to induce and support some of its members to become caring medical professionals (Fardh Kifayah).
7Optimizing medical care is a cornerstone in both Itqan (perfection) and Ihsan (excellence)
8Optimizing drug therapy is a cornerstone of proper caring for older individuals.
9Basic parameters: 1. Deciding whether a drug is indicated. 2 Basic parameters: 1.Deciding whether a drug is indicated. 2.Choosing the most appropriate drug. 3.Determining dose schedules.
104. Monitoring for effectiveness and toxicity. 5 4. Monitoring for effectiveness and toxicity. 5. Educating the patient (and family) about expected side effects.
116.Educating the patient (and family) about indications for seeking consultation.
127. Always inquire about the use of over the counter drugs, herbal preparations and dietary supplements.
138. The possibility of an adverse drug event should always be borne in mind when evaluating an elderly individual.
14Any new symptom should be considered drug-related until proven otherwise.
15Geriatric Clinical pharmacology: Addresses:Pharmacokinetics:i.e, absorption, distribution, metabolism and excretion.Pharmacodynamics:i.e, the physiologic affects of the drug.
16Adverse drug reactions. Drug interactions.Rational drug therapy for older persons.
18Age related increase in the proportion of body fat: causes increase in volume of distribution for lipid-soluble drugs:e.g: benzodiazepines.
19Age-related decrease in lean body mass: causes 10-15% decrease in total body water:The volume of distribution declines for hydrophilic drugse.g, alcohol.
20Plasma albumen concentration decreases in elderly malnorished subjects, especially those with advanced cancer.
21The plasma-binding of some drugs decreases and the unbound fraction may exceed 50% increase free drug concentrations and toxicity. e.g, Salicylate, Naproxen, Acetazolamide, Valproate.
22Age-related decrease in liver mass: 20-50%: during the age span up to 80 years. Decreased amount of drug- metabolizing enzymes.
23Associated with that, there is gradual decrease of hepatic blood flow. Decrease in clearance of drugs.
24Decrease in elimination by conjugation of some drugs by up to 25%. e.g. Theophylline.
25Decreased first-pass metabolism of some drugs that are highly extracted by the liver. e.g. Labetalol, Propranolol, Verapamil and Morphine:This results in decreased systemic bioavailability and decreased concentration.
36High affinity receptors are diminished High affinity receptors are diminished. Decline in receptor- effectar coupling. e.g: I.V isoproterenol to increase heart rate in older patients: Compromised More doses are needed.
37Sensitivity to psychoactive drugs is greater in older persons: e Sensitivity to psychoactive drugs is greater in older persons: e.g anxiolic drugs and hypnotics.
38Pain management for cancer patients: e. g Morphine and pentazocine Pain management for cancer patients: e.g Morphine and pentazocine. Duration of pain relief is prolonged with increasing age. Probably due to decreased volume of distribution.
39Anesthesia: Increased brain sensitivity to I.V fentanyl and altentanil.
41Quality of Drug Prescribing: Several dimensions:Avoidance of inappropriate medications.Appropriate utilization of indicated drugs.
42Monitoring for side effects, and drug levels. Avoidance of drug-drug interactions.Involvement of the patient and integration of his/her values.
43Quality indicators for appropriate medication use in older adults: Indicator titleDescriptionRationaleMonitoring warfarin therapyWhen warfarin is prescribed, international normalized ratio (INR) should be monitored using standard protocols.Older adults are at high risk for drug toxicity that can be identified earlier if there is close monitoring for agents with a narrow therapeutic range.Monitoring loop diuretic therapyWhen loop diuretic therapy is prescribed, electrolytes should be checked within one week after initiation and at least annuallyRisk of hypokalemia due to diuretic therapy
44Cont. Indicator title Description Rationale hypoglycemic agent When prescribing an oral hypoglycemic agent, chlorpropamide should not be used.This therapy has a prolonged half- life that can result in serious hypoglycemia and is more likely than other agents to cause the syndrome of inappropriate secretion of antidiuretic hormone.Avoid drugs with strong anticholinergic propertiesDo not prescribe drug therapies with a strong anticholinergic effect, if alternative therapies are available.These therapies are associated with adverse events such as confusion, urinary retention, constipation, and hypotension.
45Indicator title Description Rationale Avoid barbituatesIf an older adult does require the therapy for control of seizures, do not use barbiturates.These therapies are potent central nervous system depressants, have a low therapeutic index, are highly addictive, cause drug interactions, and are associated with an increased risk for falls and hip fracture.Avoid meperidine as an opioid analgesicWhen analgesia is required, avoid use of meperidine.This therapy is associated with an increased risk for delirium and may be associated with the development of seizures.Monitor renal function and potassium in patients prescribed angiotensin- converting enzyme inhibitorsIf ACE inhibitor therapy is initiated, potassium and creatinine levels should be closely monitored.Monitoring may prevent the development of renal insufficiency and hyperkalemia.Knight, El, Avorn, Ann Intern Med 2001; 135:703.
46POLYPHARMACYIn evaluating subjects on multiple medications, always consider:Over-the-counter drugs.Herbal preparations.Supplements.
47Around 50% of older patients use 5 or more medications.
48Older individuals are at greater risk for adverse drug events (ADE), due to changes in pharmacokinatics and pharmacodynamics.
49Polypharmacy increases the potential of drug-drug interactions.
50Polypharmacy is a risk factor for falls and hip fractures.
51Polypharmacy increases the risk of “Prescribing Cascades”: When an ADE is misinterpreted as a new medical condition.
52EXAMPLES OF PRESCRIBING CASCADES: Initial drug therapyAdverse drug eventSubsequent drug therapyAntipsychoticsExtrapyramidal signs and symptomsAntiparkinsonian therapyCholinesterase inhibitorsUrinary incontinenceIncontinence treatmentThiazide diureticsHyperuricemiaGout treatmentNSAIDsIncreased blood pressureAntihypertensive therapyRochon, PA, Gurwitz, JH. BMJ 1997; 315:1096Gill, SS, Mamdani, M, Naglie, G, et al. Arch Intern Med 2005;
53ANTICHOLINERGIC MEDICATIONS Associated with multiple adverse effects in older individuals:Memory impairment.Confusion, hallucinations.Dry mouth.Blurred vision.
60Cont. Therapy Therapy description Reason for concern Rarely appropriateCarisoprodolSkeletal muscle relaxantStrong anticholinergic properties, sedation and weaknessDiazepamBenzodiazepineLong half-life
61Rochon, P, Lane, c, Bronskill, S, et al. Drugs aging 2004; 21:939 TherapyTherapy descriptionReason for concernSome indication (but often misused)AmitriptylineAntidepressantStrong anticholinergic properties and sedationDiphenhydramineAntihistamineStrong anticholinergic propertiesDoxepinIndomethacinNSAIDMore CNS adverse effects than other NSAIDsMethyldopaAntihypertensiveCan cause bradycardia and exacerbate depressionOxybutyninAntimuscarinicStrong anticholinergic properties, sedation and weaknessReserpineCan induce depression and sedationTiclopidinePlatelet inhibitorPoor adverse effect profileRochon, P, Lane, c, Bronskill, S, et al. Drugs aging 2004; 21:939
62DRUG-DRUG INTERACTIONS: ONE MAJOR PROBLEM OF POLYPHARMACY
63Older adults are particularly vulnerable: e Older adults are particularly vulnerable: e.g: Increased risk of bleeding with warfarin therapy with co- administration of NSAIDs, SSRIs, Omeprazole, lipid-lowering agents, amiodarone and fluorouracil.
64Risk of hypoglycemia: Increased with concomitant use of glyburide and co-trimoxazole.
65Digoxin toxicity increases with concomitant use of clarithromycin
66Treating physicians should review all existing medications in every patient’s visit.
67STEPWISE APPROACH TO PRESCRIBING FOR OLDER ADULTS Review current drug therapyDiscontinue potentially unnecessary therapyConsider adverse drug events as a potential cause for any new symptomConsider non-pharmacological approachesSubstitute with safer alternativesReduce the doseUse beneficial therapies when indicatedRochon, P, JH, Gurwitz. The Lancet 1995;346:32.