1. Pharmacological Concepts: Geriatric Considerations Margarita Blajeva (Group 35, 2010)

2. Objectives
Describe the main physiological changes that occur with aging
Identify factors affecting absorption and distribution with the geriatric client
Describe how drugs are metabolized and excreted in the elderly
Examine the issues related to drug compliance in the elderly population

4. Demographics Geriatric population Concerns with Geriatric Pharmacology
largest consumers of Rx medications
the higher the age, the higher the number of Rx drugs a person takes
average usage ~ 3-4 drugs per senior (not uncommon to have 10+ Rx)
nature and frequency of adverse drug reactions increase with age
Concerns with Geriatric Pharmacology
changes in body metabolism
drug interactions
disease processes
changes in lifestyle

5. Aging Estimated that after 25-30 years of age, CO  by 1% a year
Most body organs  in size with age  fewer cells to carry out organ functions
Changes the way in which body will cope with metabolic processes – particularly important for pharmacology
Pharmacological changes:
Drug absorption
Drug distribution
Drug metabolism
Drug excretion

6. Drug Absorption Changes to intestinal tract: Result: Peak drug level:
decreased blood flow
reduced absorptive surface area
decreased gastric secretions
decreased motility
Result:
SLOWED rate of drug absorption
SLOWED rate of drug action
Peak drug level:
tends to decrease with age
same amount of drug will be absorbed but over a longer period of time

8. Drug Distribution Changes in body composition:
Lean body mass (muscle) % decreases
Body water % decreases
Body fat increases
(memory helper: people get weaker, fatter and dryer)
Because body fat increases with age
Lipid soluble drugs = wider distribution…
Lipid soluble drugs:
Organs with greater fat (adipose tissue/muscle) will get more than younger adults
Organs with lower fat content (liver/kidney) will get less than younger adults  liver & kidney do most of the metabolism and excretion so…
= SLOWED elimination
= GREATER half life
= GREATER duration of action

9. Drug Distribution Body water change = more drug in less fluid
GREATER concentration of drug
HIGHER concentration of drug in elderly patient
Water soluble drugs:
Less bodily fluid to dissolve in
Less distribution to organs with high adipose content
GREATER concentration of drug in certain organs
GREATER pharmacological effects

10. Drug Metabolism In general… Why? Mixed-function oxidase system
RATE of drug metabolism decreases with age
…but there is much variability
Why?
Decreased blood flow to liver (less coming in/fewer resources available)
Decreased production of liver enzymes
Mixed-function oxidase system
Enzymes responsible for oxidizing drugs
Tend to be strongly affected by the aging process
Drugs that are oxidized (eg. Benzodiazepines) will be metabolized slower…
 longer duration of drug action

11. Drug Excretion Main routes of elimination: Renal & Gastrointestinal
“Enterohepatic cycling”
Some drugs also are eliminated by travelling through the liver, biliary tract, then intestinal tract
Some of these drugs, which undergo enterohepatic cycling, will not be eliminated at a final step but will re-enter circulation
 increased half-life & duration

12. Drug Excretion Renal excretion
One of the most greatly impacted systems by aging process
Renal function decreases across the board:
 glomerular filtration rate (GFR)
 creatine clearance
What this means for medications that are primarily excreted by renal system:
 duration of action
 plasma drug concentration
pharmacological action
Therefore dosage must be reduced accordingly.

13. Drug Compliance Extremely important issue in elderly…
Challenges with elderly compliance
Complicated dosing regimens
Confusion
age related memory loss
pathologic processes (Alzheimer’s, dementia, etc.)
live alone
lack of instructions for drug taking procedures
confusion tends to be directly proportional to number of Rx medications taken
Presence of unpleasant side effects of drug discourages use
“Polypharmacy” = multiple drug prescriptions

14. Drug Compliance Other considerations: Helping compliance:
Understanding and training – compliance may be increased dramatically with thorough instructions about the uses and methodology involved with a given medication
Form – patients may have difficulty with certain forms of medications (e.g. swallowing large capsules)
Container – may be difficult to open, or difficult to read and understand
Helping compliance:
Understanding of the how and why: this should be done by physician but often is not
Developing easy to follow schedule
e.g. Pill A after lunch/ Pill B before bed

15. Drug Compliance BLISTER PACK!!!
A possible solution to patient compliance problems

16. Summary Demographics & Aging Drug Absorption Drug Distribution
Drug Metabolism
Drug Excretion
Compliance

17. THE END