Presentation on theme: "DRUG PRESCRIBING FOR THE ELDERLY"— Presentation transcript:
1 DRUG PRESCRIBING FOR THE ELDERLY بسم الله الرحمن الرحيمDRUG PRESCRIBING FOR THE ELDERLYAly A. Misha’l MD, FACPSenior consultant in Medicineand EndocrinologyAmman-Jordan
2 Senility 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
6 Caring 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).
7 Optimizing medical care is a cornerstone in both Itqan (perfection) and Ihsan (excellence)
8 Optimizing drug therapy is a cornerstone of proper caring for older individuals.
9 Basic 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.
10 4. Monitoring for effectiveness and toxicity. 5 4. Monitoring for effectiveness and toxicity. 5. Educating the patient (and family) about expected side effects.
11 6.Educating the patient (and family) about indications for seeking consultation.
12 7. Always inquire about the use of over the counter drugs, herbal preparations and dietary supplements.
13 8. The possibility of an adverse drug event should always be borne in mind when evaluating an elderly individual.
14 Any new symptom should be considered drug-related until proven otherwise.
15 Geriatric Clinical pharmacology: Addresses:Pharmacokinetics:i.e, absorption, distribution, metabolism and excretion.Pharmacodynamics:i.e, the physiologic affects of the drug.
16 Adverse drug reactions. Drug interactions.Rational drug therapy for older persons.
18 Age related increase in the proportion of body fat: causes increase in volume of distribution for lipid-soluble drugs:e.g: benzodiazepines.
19 Age-related decrease in lean body mass: causes 10-15% decrease in total body water:The volume of distribution declines for hydrophilic drugse.g, alcohol.
20 Plasma albumen concentration decreases in elderly malnorished subjects, especially those with advanced cancer.
21 The 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.
22 Age-related decrease in liver mass: 20-50%: during the age span up to 80 years. Decreased amount of drug- metabolizing enzymes.
23 Associated with that, there is gradual decrease of hepatic blood flow. Decrease in clearance of drugs.
24 Decrease in elimination by conjugation of some drugs by up to 25%. e.g. Theophylline.
25 Decreased 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.
36 High 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.
37 Sensitivity to psychoactive drugs is greater in older persons: e Sensitivity to psychoactive drugs is greater in older persons: e.g anxiolic drugs and hypnotics.
38 Pain 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.
39 Anesthesia: Increased brain sensitivity to I.V fentanyl and altentanil.
41 Quality of Drug Prescribing: Several dimensions:Avoidance of inappropriate medications.Appropriate utilization of indicated drugs.
42 Monitoring for side effects, and drug levels. Avoidance of drug-drug interactions.Involvement of the patient and integration of his/her values.
43 Quality 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
44 Cont. 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.
45 Indicator 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.
60 Cont. Therapy Therapy description Reason for concern Rarely appropriateCarisoprodolSkeletal muscle relaxantStrong anticholinergic properties, sedation and weaknessDiazepamBenzodiazepineLong half-life
61 Rochon, 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
62 DRUG-DRUG INTERACTIONS: ONE MAJOR PROBLEM OF POLYPHARMACY
63 Older 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.
64 Risk of hypoglycemia: Increased with concomitant use of glyburide and co-trimoxazole.
65 Digoxin toxicity increases with concomitant use of clarithromycin
66 Treating physicians should review all existing medications in every patient’s visit.
67 STEPWISE 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.