Definition: Pharmacokinetics
How a drug is absorbed, distributed, metabolized
and excreted
Definition: Pharmacodynamics
How the body is affected by a drug at the
cellular level and in relation to the target organ
Elimination/ Serum Half-Life
the time required to decrease the drug
concentration by one half of its original value
Pharmacokinetics
- Absorption of oral (PO) medications can be
affected by reduced gastric acid, increased
gastric pH, delayed gastric emptying, and
the presence of other substances (ie. food). - Most PO meds are absorbed in the small
intestine. - It takes 5 half-lives to reach steady-state
concentrations after a drug is initiated OR
to eliminate a drug from the body after the
drug is discontinued.
Age-Related Physiological Changes that Affect the
Action of Medications in Older Adults
- Decline in renal function (eGFR)
- Hepatic blood flow decline
- Decreased muscle mass and water content
- Low serum albumin (protein)
- Altered receptor sensitivity
What Affects medication-taking Behavior?
- Motivation
- Knowledge about the medication
- Cultural and psychosocial influences
- Physical ability to remove the substance from the container and administer it
- Ability to swallow oral preparations
- Additional skills related to administer nasal, transdermally, SC and by other routes
What is Polypharmacy
More medications than are clinically indicated.
- Not about the number of medication
- About the appropriateness & combination of
medications
Consider:
- All medications have side-effects
- Older adults are more likely to experience stronger
side-effects
- ALWAYS consider whether the benefit outweighs the
riskFunctional
Consequences
Associated with
Medications in
Older Adults
- Disease or polypharmacy may alter the
therapeutic effects of a medication - Adverse effects
- Anticholinergic Adverse Effects
- Altered mental status
- Antipsychotics in people with dementia
- Tardive Dyskinesia and Drug-Induced
Parkinsonism
Adverse Effects Factors that increase older
adults’ risk for adverse events are:
- Higher number of medications
- Malnourishment or dehydration
- Multiple comorbidities
- An illness that interferes with cardiac, renal or
hepatic function - Cognitive impairment
- History of medication allergies or adverse effects
- Fever that can alter the action of certain
medications - Recent change in health
- Certain medications: anticoagulants/
antiplatelets, antidiabetics, NSAIDs, CNS drugs
Anti-Cholinergics
- Anticholinergics are drugs that block the
action of acetylcholine, a neurotransmitter,
or a chemical messenger, that transfers
signals between certain cells to affect how
your body functions. - They inhibit the parasympathetic (stabilizing) nervous
system.
Anti-psychotics
- Increasingly used in LTC facilities.
- US is restricted by FDA to prescribe
antipsychotics ONLY for psychotic symptoms,
not for wandering, anxiety, or insomnia. - Not similar in Canada.
- Studies confirm need for education of
nursing staff to improve knowledge,
attitudes and beliefs about antipsychotic use
for nursing home residents.
What are Anti-cholinergics used for
- OTC medications used for coughs, colds, flu and
sleep problems. - Treatments for older adults (antihistamines,
antidepressants, antipsychotics, CV agents,
antiparkinsonians, GI and urinary agents). - Contribute to long-term cognitive impairment.
- Can counteract the effects of cholinesterase
inhibitors, a primary treatment for dementia. - Safer alternatives usually exist; try to advocate
for them.
Tardive Dyskinesia
- Rhythmic involuntary movements of the
trunk, extremities, jaw, lips, mouth or
tongue. - Wormlike movements of the tongue,
chewing, grimacing, lip smacking, jaw
clenching, eye blinking, and side-to-side jaw
movements. - Can begin 3-6 months after initiation of
antipsychotic use and persist after
medication is discontinued.
Drug-Induced Parkinsonism
- Parkinson-like symptoms such as shaking,
involuntary or poorly controlled movement. - Condition can be easily misdiagnosed as
Parkinsonism and patients are started on
new medications. - Manifestations can be reversed if the drug is
stopped.
BEERS
- A list of medications known to increase
the risk of delirium and other adverse
reactions in older adults. - These medications should not be
prescribed for older adults unless there is
a greater benefit-risk ratio for a particular
situation, and then should only be used
for the shortest possible duration.
Medications are safest
and most therapeutic
when taken as
prescribed and when
they are regularly
reviewed
Nursing Goals of Assessment
- Determine effectiveness of existing
regimen - Identify any factors that interfere with the
current regimen - Ascertain risks for adverse effects or
altered therapeutic actions - Detect adverse medication effects
- Identify teaching needs regarding
medications
Scope of Medication Assessment
- Prescription and OTC medications (all routes)
taken regularly - Medications taken “as needed” or PRN
- Vitamins, minerals, and dietary supplements
- Herb and Folk remedies and complementary/
alternative modalities - Alcohol, substances
- Smoking/inhaling
Medication Reconciliation
- Identifying medications at any transition in
care - View all the medications
- Address ability to get prescriptions filled
- Address issues that affect adherence
- Allow the client to ask questions
Nursing Intervention
- Recommend all older adults have a list of what the are currently
taking - Ensure clients and caregivers understand the appropriate use of
“as needed” (PRN) medications - Encourage use of devices and systems to improve medication
adherence (ie. pillboxes, blisterpacks, etc.) - Encourage nonpharmacologic approaches to manage behavior
- Decrease number of medications
- Assess for financial barriers: Generic vs brand
Interdisciplinary
Intervention
- Encourage a review of medications with primary
physician at every visit - The pharmacist’s role is to review specific
actions and interactions of medications - Advocate for referral to Seniors Clinic for followup of complex clients
- Refer to Home Care if assistance is required for
medication administration - Social Worker referral for assistance with
financing
A healthy 70-year-old has been using diphenhydramine (Benadryl) for allergic rhinitis. One week later, the client begins to exhibit signs of confusion and disorientation. The spouse calls the primary care facility to speak with the nurse. Which event should the nurse suspect first?
Question 1Select one:
a.
The older adult has dehydration, leading to delirium.
b.
The older adult is having transient ischemic attacks/strokes.
c.
The older adult has an overwhelming infection.
d.
The older adult is experiencing an adverse drug effect.
The older adult is experiencing an adverse drug effect.
A nurse assesses an older adult who has been having a difficult time sleeping throughout the night and incontinence. Which question by the nurse will best provide clues to these problems?
Question 2Select one:
a.
“What medications do you take when you need to stay asleep?”
b.
“What did your health care practitioner tell you about your medications?”
c.
“How many times a night do you get up to urinate?”
d.
“What beverages do you drink on a regular basis?”
“What beverages do you drink on a regular basis?”
A nurse initiates an acute care for elders unit in a medical facility. Which factor should the nurse include when teaching the nursing staff about delivering medications to the older adults on the unit?
Question 3Select one:
a.
Drug metabolism shifts from the liver to the kidneys as individuals age.
b.
Older adults tend to need more frequent doses of a drug to achieve therapeutic effect.
c.
Older adults face an increased risk of adverse medication effects.
d.
Older adults tend to achieve clearance of medication faster than do younger clients.
Older adults face an increased risk of adverse medication effects.
