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

1. Pharmacological Concepts: Geriatric ConsiderationsMargarita 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 • 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: • 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… 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: • 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!!!

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

17. THE END