SWK-597-43W Chapter 10

1. Chapter 10
Drugs and the
Older Adult

2. Objectives (1 of 3)
1. Discuss the physiologic changes that
occur as we age that affect our response
to drug administration, including
absorption, distribution, metabolism, and
excretion.
2. Describe the symptoms of anti-cholinergic
syndrome and identify classes of drugs
with anti-cholinergic side effects.

3. Objectives (2 of 3)
3. Describe the symptoms of serotonin
syndrome and identify classes of drugs
that have serotonergic activity.
4. Identify classes of drugs that should be
avoided in the older patient as outlined in
Beer’s criteria and STOPP.
5. Identify classes of drugs that are
underutilized in the older patient, as
described in START.

4. Objectives (3 of 3)
6. Discuss drugs of abuse in older adults.
7. Discuss the use of herbal therapy and
supplements.
8. Describe the increase in drug side effects
that occur as the result of taking an increased
number of drugs
9. Discuss how to manage polypharmacy.
10.Discuss the principle of Go Low – Go Slow in
the use of drugs in the older patient.

5. Introduction (1 of 4)
• Number of drugs used by older patients
has increased dramatically
• People age 65 and older:
– Make up 13% of the U.S. population
– Buy 33% of the prescription drugs
• 95% of 70-year-old Americans reportedly
use at least one medication

6. Introduction (2 of 4)

7. Introduction (3 of 4)
• Food and Drug Administration (FDA)
– Responsible for approval of prescription and
non-prescription drugs
– Does not require drugs to be tested in older
populations
– Does not regulate the production of herbal
medications and supplements

8. Introduction (4 of 4)
• Many drug interactions are due to both
pharmacokinetic and pharmacodynamic
interactions
– Phamacokinetics
• What the body does to a drug
– Pharmacodynamics
• What the drug does to the body

9. Pharmacokinetics (1 of 15)
• Drug absorption
– Depends on how a drug is administered:
• Oral, sublingual, intranasal, intravenous,
intramuscular, topical, subcutaneous, or inhaled
• Oral administration is most common
– Each administration route could potentially be
impacted by the aging process

10. Pharmacokinetics (2 of 15)
• Oral administration
– Most drug absorption occurs in the small
intestine
– Rate of gastric emptying needs to be considered
• Slowed gastric emptying increases the amount of
time it takes to attain maximal drug concentrations in
the blood without a change in maximal drug
concentration
– Oral administration does not significantly affect
the clinical response to drugs

11. Pharmacokinetics (3 of 15)
• Transdermal administration
– Administration through the skin
– Convenient method for administering a steady
amount of a drug over a prolonged period
– Age-related changes in skin can impact
absorption
• May lead to lower concentrations in the blood

12. Pharmacokinetics (4 of 15)
• Drug distribution
– Drugs distribute throughout the body based
on their physicochemical properties
– Most important is the hydrophilicity or
lipophilicity of the drug
– Effect of aging on distribution is very much
dependent on the specific drug

13. Pharmacokinetics (5 of 15)
• Drug metabolism
– Liver is the main organ of drug metabolism
– Drug metabolizing enzymes are not
significantly affected by aging (in the absence
of disease)
– Other changes are more significant
• Decreased blood flow in the liver decreases
extraction of drugs from the blood and slows
metabolism

14. Pharmacokinetics (6 of 15)
• Drugs with a high extraction from the
blood are most affected with age
– Increases half-life of these kinds of drugs
– Example: half-life of diazepam (valium)
• 20 hours in a person’s twenties
• 80 hours in a person’s eighties

15. Pharmacokinetics (7 of 15)

16. Pharmacokinetics (8 of 15)

17. Pharmacokinetics (9 of 15)
• Some drugs metabolize to active
metabolites
– Drug breaks down but is transformed into
another active drug
– Example: diazepam
• Metabolizes to three active metabolites
• Single dose may continue producing effects for 6
days

18. Pharmacokinetics (10 of 15)
• Drugs are metabolized in the liver by a
number of enzymes
– Major group belongs to the class of
cytochrome P450s, which has many subtypes
– Vary considerably based on a person’s:
• Genetic background, including ethnic background
• Previous exposure to drugs
• Current drug regimen

19. Pharmacokinetics (11 of 15)
• Many therapeutically important drugs will
inhibit the CYP450 enzymes
– Slows metabolism of other drugs
– Drug levels in blood will increase, potentially
leading to toxicity

20. Pharmacokinetics (12 of 15)
• Enzyme induction
– Occurs when the liver produces more of the
metabolizing enzyme after exposure to the
drug
– Leads to:
• Increased metabolism of drugs metabolized by this
specific enzyme
• Lower blood levels of the drug
• Decreased therapeutic efficacy

21. Pharmacokinetics (13 of 15)

22. Pharmacokinetics (14 of 15)
• Drug excretion
– Ability to excrete drugs and metabolites is
altered as a person ages
– Most are excreted in urine through the kidneys
• Another route is through the bile into the intestines
– Decreased kidney function with age further
decreases excretion of drugs
– Effect on drug excretion depends on properties
of the drug

23. Pharmacokinetics (15 of 15)

24. Pharmacodynamics
• Involves examining how drug responses
change based on changes in cellular
responses to drugs over the life span
• Depends on the changes that occur in the
drug’s targets
• Knowing why a person responds to
specific medications can help the
physician make decisions about the best
drug to prescribe

25. Pharmacogenomics (1 of 2)
• Study of how a person’s genetic
background determines the
pharmacokinetic and pharmacodynamic
responses to drugs
• Widespread variability in how older adults
metabolize drugs based on the levels of
subtypes of cytochrome P450 enzymes
– Lab tests are available to determine the levels
of these enzymes in a patient

26. Pharmacogenomics (2 of 2)
• Advances are also being made in:
– Understanding how genetics change the
response to drugs
– Precision dosing as a part of personalized
medicine

27. Anti-Cholinergic Syndrome
(1 of 9)
• Collection of symptoms related to the
effects of agents that block acetylcholine
in the nervous system
• Greater risk of occurrence in older adults
• Polypharmacy is an important contributor

28. Anti-Cholinergic Syndrome
(2 of 9)
• Cholinergic system
– Neurotransmitter acetylcholine is involved in:
• Learning and memory in the brain
• Central nervous influence on organs
• Parasympathetic nervous system

29. Anti-Cholinergic Syndrome
(3 of 9)
• Some classes of drugs have emerged from
the large class of antihistamines
• Antihistamines have widespread usage
– Related classes of drugs act as antagonists at
the muscarinic subtype of cholinergic receptors
• Possible to take multiple medications for
multiple conditions that all have antagonist
effects at the muscarinic cholinergic
receptor

30. Anti-Cholinergic Syndrome
(4 of 9)

31. Anti-Cholinergic Syndrome
(5 of 9)

32. Anti-Cholinergic Syndrome
(6 of 9)
• Important concern is the effects of
polypharmacy on cognition
– Many species show a slow and continuous
decline in the cholinergic forebrain system
– A rapid decline of this system can result in
dementia at an early age
– If medications are used that work against
these same receptors, the patient’s symptoms
will worsen

33. Anti-Cholinergic Syndrome
(7 of 9)
• Other syndromes
– Serotonin syndrome
• Medications that increase serotonin in the brain:
– Antidepressants
– Selective serotonin reuptake inhibitors (SSRIs)
– Some opioid pain relievers
– Trazadone (used to help induce sleep)
– Dextromethorphan (cold medication)

34. Anti-Cholinergic Syndrome
(8 of 9)

35. Anti-Cholinergic Syndrome
(9 of 9)
• Symptoms of serotonin syndrome
– Vary from very mild to life threatening
– Hyperreflexia, clonus, and altered mental
status are commonly seen
– Symptoms resolve with discontinuation of the
drugs

36. Drug Dependence, Misuse,
and Addiction (1 of 2)
• Drugs used to treat older adults can:
– Have serious side effects (pain relievers)
– Lead to tolerance and dependence (sleep
aids)
• Discontinuation can result in symptoms of
withdrawal
• Strict limits should be placed on the use of
drugs with misuse potential

37. Drug Dependence, Misuse,
and Addiction (2 of 2)
• Alcohol misuse
– Can lead to dependence and uncontrolled use
– Health consequences:
• Decreased cognitive function
• Cardiomyopathy
• Hepatitis and cirrhosis of the liver
• Increased risk of falls when combined with
sedatives
• Can exacerbate the side effects of medications

38. Beers’ List and
STOPP/START (1 of 3)
• Beers Criteria for Potentially Inappropriate
Medication
– Identifies medications inappropriate for use by
older adults
– Important for healthcare practitioners to
consider all drug classes before prescribing
for older populations

39. Beers’ List and
STOPP/START (2 of 3)
• Screening Tool of Older People’s Potentially
Inappropriate Prescriptions (STOPP)
– Divides findings into nine systems
– Indicates care with use of duplicate drug
classes
– Same team later developed the Screening Tool
to Alert Doctors to Right Treatments (START)
• Retained the same nine systems as STOPP

40. Beers’ List and
STOPP/START (3 of 3)

41. Herbal Medicines and
Supplements (1 of 5)
• All age groups are using more
nutraceuticals
– Older adults consume more than any other
age group
• Purpose of use varies considerably
depending on current popular and medical
opinion
– Women use more dietary supplements than
men

42. Herbal Medicines and
Supplements (2 of 5)

43. Herbal Medicines and
Supplements (3 of 5)
• Nutraceuticals may not be safe and
effective
– Not regulated by the FDA unless they are
shown to be a significant risk to public health
– Over-the-counter remedies are drugs and can
have significant side effects and interactions
with other medications

44. Herbal Medicines and
Supplements (4 of 5)

45. Herbal Medicines and
Supplements (5 of 5)
• Manufacturers of nutraceuticals cannot
advertise that they are treatments for any
diseases
– No dosage can be recommended for taking them
– Consumers are expected to find the proper
dosage themselves, for any given indication
• More research needs to be done to
determine how nutraceuticals can best be
used

46. Polypharmacy (1 of 6)
• Older patients take more medications than
younger patients in part due to:
– Increased incidence of chronic disease
– Media pressure from the pharmaceutical
industry
• Iatrogenic component
– Practitioners add additional medications to
treat side effects

47. Polypharmacy (2 of 6)

48. Polypharmacy (3 of 6)
• Basic common-sense steps are generally
taken to reduce the number of drugs
prescribed for a patient
• First step is being aware of all medications
(and dosages) being taken, including
herbal and dietary supplements

49. Polypharmacy (4 of 6)

50. Polypharmacy (5 of 6)
• Important to consider:
– Clinical signs associated with each medicine
– Possible side effects
– How each drug is being taken
• Review may lead to changing medications
to obtain a more favorable side effect
profile
– Avoid treating side effects with another drug if
possible

51. Polypharmacy (6 of 6)
• If at all possible, only start one drug at a time
– May take some time for the drug to reach
therapeutic levels in the blood
• Important to know whether the dose should
be adjusted downward to account for hepatic
or rental metabolism
– Use the phrases “Go Low and Go Slow” and
“KISS—Keep It Simple Seriously” when
evaluating medications in older patients