Drug Use in the Elderly

UMMS CRIT Module II: Drug Therapy in the Elderly

Jerry H. Gurwitz, MDChief, Division of Geriatric MedicineUniversity of Massachusetts Medical SchoolUMass Memorial Medical Center

UMMS CRIT 2012 Module II: Drug Therapy in the Elderly

Advancing Geriatrics Education (AGE) A UMMS initiative funded by the Donald W. Reynolds Foundation

It is much easier to write upon a disease than upon a remedy.

The former is in the hands of nature and a faithful observer with

an eye of tolerable judgement cannot fail to delineate a likeness.

The latter will ever be subject to the whim, the inaccuracies and

the blunder of mankind.

William Withering (1741-1799)



A desire to take medicine is, perhaps, the great feature which

distinguishes man from other animals.

Sir William Osler, 1891



“I know of no way to end an office visit as satisfactorily and as efficiently as by writing a prescription. The patient knows that the visit is over and is expected to leave. He has something in his hand that he thinks will help him and obtaining it required an office visit.”

Marcus Reidenberg, MDEditor Emeritus, CP&T



Drug Use in the Elderly

• 57% of all elderly use > 5 drugs per week

• 19% of elderly use > 10 drugs per week



• Overuse

• Inappropriate prescribing

• Underuse

Suboptimal Medication Use

Hanlon JT et al. JAGS. 2001;49: 200-9. Fisk D et al. Arch Intern Med. 2003;163: 2716-2724.



Polypharmacy is not necessarily bad!

Polypharmacy



• Any transition - hospitalizations, discharges, ER visits, subacute

care stays

• New meds, different doses…

• Changes from generic to brand- nomenclature, color and/or shape

Drug Regimen Changes ~They are very common!



• The more providers and visits, the more medications are prescribed

• 2/3 of all physician visits end with a prescription

• Expectations of the patient to receive a prescription

• Lack of communication between prescribers

• Self-treatment: unbeknownst to the physician

Why so many changes?



• Increased risk of adverse drug events and near-misses

• Noncompliance or nonadherence leading to poor outcomes

• Increased costs

Impact on the Patient



• Multiple co-existing illnesses

• Polypharmacy: redundant effects and drug-drug interactions

• Adverse drug effects nonspecific

• Pharmacologic changes with aging

• Medical error

Factors Influencing Drug Effects and Risk of Adverse Effects in the Elderly



• Absorption• Distribution• Metabolism• Excretion

Pharmacokinetics: Changes with Aging



Body Composition Changes in Adult Men with Aging

Age Group Body Weight (kg) Body Fat (kg) Muscle Mass

(kg)

20-29 80 15 24

30-49 81 19 20

60-69 79 23 17

70-79 80 25 13

Data adapted from Cohn et al, 1980





• Phase I reactions- primarily oxidative reactions– Decline in efficiency with aging

• Phase II reactions- conjugation reactions– No decline in efficiency with aging

Hepatic Metabolism of DrugsChanges with Aging



Renal Function: Changes with Aging

AgeCR

EAT

ININ

E C

LE

AR

AN

CE



t1/2 ~ Vd/Clearance



Pharmacodynamics: Changes with Aging



Clinical Pearl

Any new symptom in an elderly patient should be considered a drug side effect until proven otherwise.

Jerry Avorn, MD



The Prescribing Cascade

Drug 1

ADE

Drug 2



The Prescribing Cascade

Metoclopramide

Extrapyramidal Effects

Levodopa Rx



Case-Control Study Design

Metoclopramide:Yes or No?

Metoclopramide:Yes or No?

BEGIN

L-dopaRx

Controls

CLASSIFY/COMPARE



Results

Metoclopramide users were over three times more

likely to begin use of L-dopa therapy compared with

non-users (OR=3.09; 95% CI 2.25 to 4.26).



Likelihood of L-dopa Treatment by Metoclopramide Dose



Conclusion

Metoclopramide confers an increased risk for the

initiation of treatment generally reserved for the

managment of idiopathic Parkinson’s disease.

Avorn et al, JAMA, 1995



• Medication reconciliation – at time of transitions

• Anticipate errors – prescribing & monitoring

• Watch out for prescribing cascades

• Simplify the medication regimen

• Identify obstacles (costs, cognitive impairment)

• Enlist family/nursing/PCP support & involvement

• Make sure there is good follow-up

Improving the Quality of Prescribing to Older Adults



Lessons from the Case

Documents

Drug Use in the Elderly