The document discusses challenges in pharmacotherapy for geriatric patients. It notes that illness is more common in older adults, leading to high rates of polypharmacy. Age-related changes can impact absorption, distribution, metabolism and excretion of drugs. This generally results in lower clearance and increased sensitivity to medications. Drug-drug and drug-disease interactions are also more common. The document provides prescribing pearls like starting low doses and avoiding high risk medications. It emphasizes the need for careful monitoring to optimize outcomes for geriatric patients.

1. DR. VANDANA TAYAL
ASSISTANT PROFESSOR
PHARMACOLOGY
Medication in Geriatric
Patients

2.  Successful pharmacotherapy means using
 the correct drug
 at the correct dose
 for the correct indication
 in an individual patient

3. TODAY’S TOPICS
Challenges of Geriatric Pharmacotherapy
•Medication use patterns
•Age related changes in Pharmacokinetics &
Pharmacodynamics
Interactions – Drug-drug, Drug-disease
Drugs to avoid
Prescribing Pearls for elderly

4. MEDICATION USE PATTERN

5. Extent of Medication use
 Illness is more common in older persons -
Cardiovascular disease, Diabetes Mellitus, Arthritis,
Gastrointestinal disorders, Respiratory diseases, Bladder
dysfunction
 Polypharmacy - Elderly = 12% of population but
32% of prescriptions

6. Average use for persons 65
 2 to 6 prescription drugs
 2 to 4 over-the-counter medicine
 1 to 3 vitamin and herbal supplement

7.  More adverse drug reactions
 Drug Interactions
 Increased cost
 Decreased adherence to drug regimens
Polypharmacy Leads to?

8. Factors contributing to Non-adherence
 Large number of medications
 Expensive medications
 Complex or frequently changing schedule
 Adverse reactions
 Confusion about brand name/trade name
 Difficult-to-open containers
 Rectal, vaginal, SQ modes of administration
 Limited patient understanding

9. Age related changes relevant to
drug prescribing

10. Unique Pharmacokinetics and Pharmacodynamics:
normal part of the aging process
PK
 Absorption
 Distribution
 Metabolism
 Excretion
PD
 Receptor numbers, affinity, or post-receptor
cellular effects
“Start low, go slow”!

11. Effects of Aging on Absorption
 Rate of absorption may be
delayed
 Lower peak concentration
 Delayed time to peak concentration
 Overall amount absorbed
(bioavailability) is unchanged

12. Effects of Aging on Volume of Distribution
(Vd)
Aging Effect Vd Effect Examples
 body water  Vd for hydrophilic
drugs
ethanol, lithium
 lean body mass  Vd for drugs that
bind to muscle
digoxin
 fat stores  Vd for lipophilic
drugs
diazepam, trazodone
 plasma protein
(albumin)
 % of unbound or
free drug (active)
diazepam, valproic acid,
phenytoin, warfarin
 plasma protein
(1-acid glycoprotein)
 % of unbound or
free drug (active)
quinidine, propranolol,
erythromycin, amitriptyline

13. Effects of Aging on Hepatic Metabolism
 Metabolic clearance of drugs by the liver may be
reduced due to:
 decreased hepatic blood flow
 decreased liver size and mass
 Examples: morphine, meperidine, metoprolol,
propranolol, verapamil, amitryptyline,
nortriptyline

14. Effects of Aging on the Kidney
 Decreased kidney size
 Decreased renal blood flow
 Decreased number of functional nephrons
 Decreased tubular secretion
 Result:  glomerular filtration rate (GFR)
 Decreased drug clearance: atenolol, gabapentin,
H2 blockers, digoxin, allopurinol, quinolones

15. Pharmacodynamics and Aging
 Generally, lower drug doses are required to achieve
the same effect with advancing age.
 Receptor numbers, affinity, or post-receptor cellular
effects may change.
 Changes in homeostatic mechanisms can increase or
decrease drug sensitivity.

16. Pharmacodynamics
 Some effects are increased
 Fentanyl, diazepam, morphine, theophylline
 Alcohol causes increased drowsiness and
lateral sway in older people than younger
people at same serum levels
 Some effects are decreased
 Diminished response to isoproterenol and
beta -blockers

17. PK and PD Summary
 PK and PD changes generally result in decreased
clearance and increased sensitivity to medications in
older adults
 Use of lower doses, longer intervals, slower titration
are helpful in decreasing the risk of drug intolerance
and toxicity
 Careful monitoring is necessary to ensure successful
outcomes

18. High Risk Medications

21. “Tips” for Safe Traditional NSAID Use
 Substitute acetaminophen when possible around the
clock instead of NSAID
 Use PRN when possible
 Use lowest dose possible
 Use for acute flare for 7-10 days then discontinue
 When necessary for chronic use, insist on routine 3
monthly BUN and CBC

24. Drug-Interactions

25.  Likelihood  as number of medications 
 May lead to adverse drug events
 Most common DDIs:
 cardiovascular drugs
 psychotropic drugs
 Most common drug interaction effects:
 confusion
 cognitive impairment
 hypotension
 acute renal failure
Drug-Drug Interactions (DDIs)

26. Common Drug-Drug Interactions
Combination Risk
Epinephrine + Thiazide/ furosemide
diuretic
Hypokalemia, arrythmia
NSAID + diuretic/antihypertensive Lessen efficacy of anti-HT
ACE inhibitor + potassium / K sparing
diuretic
Hyperkalemia, hypotension
Digoxin + diuretic Electrolyte imbalance; arrhythmia
Benzodiazepine + antidepressant
Benzodiazepine + antipsychotic
Sedation; confusion; falls
CCB/nitrate/vasodilator/diuretic Hypotension
Doucet J, Chassagne P, Trivalle C, et al. Drug-drug interactions related to hospital admissions in older adults: a
prospective study of 1000 patients. J Am Geriatr Soc 1996;44(9):944-948.

27. Common Drug-Disease Interactions
Combination Risk
NSAIDs + CHF
Thiazolidinediones + CHF
Fluid retention; CHF exacerbation
NSAIDs + HTN Fluid retention; decreased effectiveness of
diuretics
NSAIDs + gastropathy Increased ulcer and bleeding risk
Metformin + CHF Hypoxia; increased risk of lactic acidosis
BPH + anticholinergics Urinary retention
CCB + constipation
Narcotics + constipation
Anticholinergics + constipation
Exacerbation of constipation

28. PRINCIPLES OF PRESCRIBING

29. Consider non-pharmacologic agents
Avoid prescribing prior to diagnosis
Complete drug history, including herbs and
nonprescription drugs (Vitamins)
Have patient bring in medications at each visit
Consider drug-drug and drug-disease
interactions
Adjust doses for renal and hepatic impairment
 Start low, go slow
Prescribing Pearls

30. Prescribing Pearls
Prescribe a drug that will treat more than
one existing problem
Examples:
– calcium channel blocker or beta blocker to
treat both hypertension and angina pectoris
– Alpha-blocker to treat both hypertension and
prostatism

31. Avoid starting 2 agents at the same time
Keep regimen as simple as possible
Discontinue a drug if it is ineffective or
intolerable adverse effects occur
Consider risk vs. benefit
Prescribing Pearls

32. Consider the cost
Provide legible written instructions
Instruct caregivers as needed
Prescribing Pearls

33. Conclusions

34. Summary
 Successful pharmacotherapy is a challenge in
geriatric population
 Age alters PK and PD
 ADEs are common among the elderly
 Risk of ADEs can be minimized by appropriate
prescribing

35. THANK YOU