Pharmacotherapeutics (Mimi's with edits!:)) Flashcards
difference between pharmacokinetics vs pharmacodynamics
Pharmacokinetics- What the body does to the drug
Pharmacodynamics- What the drug does to the body
Pharmacokinetics can be altered by (3)
- disease
- environment
- meds
is absorption changed with aging?
minimally altered by aging
how does aging affect absorption?
- decreased size of absorptive surface
- increased gastric pH
- decreased splanchnic blood flow
- decreased Gastric motility
what is absorption altered by
- Drugs that
- alter stomach PH
- inc/dec GI motility
- cause mucosal damage
- prevent absorption
- reduce active transport mechanisms - Disorders that change GI motility: DM, IBS, GERD, dumping syndrome
- Bariatric surgeries, gastroparesis, achalasia, biliary dyskinesia, hiatal hernia, spastic esophagus, GI obstruction, diarrhea, constipation, pseudo-obstruction, infections
Drugs that Delay Gastric Emptying
ABCDGHLOPT
Alcohol
Aluminum hydroxide antacids
Anticholinergics
Beta Blockers
Calcium channel blockers
Cyclosporin
Diphenydramine
GLP1
GLP2
H2 receptor antagonists
Levadopa
Lithium
Ondansetron
Opioids
Phenothiazines Antipsychotics
Proton pumpinhibitors
Tricyclic antidepressants
What physiologic changes occur with aging that affects distribution?
- lean muscle replaced with adipose tissue
- reduction in total-body water content
- decreased serum albumin
how does increased adipose tissue affect distribution
Increased adipose tissue leads to lipophilic drug changes such as:
* deceased serum levels
* increased volume of distribution
* increased metabolism
* increased elimination half life
how does low total-body water content affect distribution
Low total-body water content = dec vol of distribution for Hydrophilic meds (e.g., digoxin, lithium) = higher serum levels
how does decreased serum albumin affect distribution
occurs with poor nutrition, impaired renal function, and many chronic medical conditions. this leads to:
-increased “free” drug levels
- Increased risk of SE when high protein-binding drugs are used
how does aging impact metabolism?
Reduction in CYP450 metabolism d/t age-related reduced hepatic blood flow and liver size
- Drugs can inhibit or induce P450 enzymes
- Px if one drug inhibits P450 and another requires it for metabolism
- Px if one drug induces P450 and leads to rapid metabolism of another drug
what are the physiologic changes with aging on excretion?
Impacted by decrease in Renal tubular function and GFR
why is there physiologic changes in excretion with aging
- d/t a loss in muscle mass, a patient’s serum creatinine may be normal despite renal impairment
- Creatinine is a waste product produced by muscles from the breakdown of a compound called creatine.
- Creatinine is removed from the body by the kidneys, which filter almost all of it from the blood and release it into the urine.
What are reasons that pharmacodynamics change as we age?
altered receptor affinity or numbers
post-receptor alterations
impairment of homeostatic mechanisms
Older patients are more sensitive to drugs that suppress the CNS, leading to what types of SE?
delirium
confusion
agitation
The simultaneous use of multiple drugs by a single patient, for one or more conditions; >5 drugs
what is this term?
Polypharmacy
Most common in older adults
Complications of polypharmacy
Increased adverse drug reactions, drug-drug interactions, drug-disease interaction
Cost burden
Increase risk of hospitalization
Decreased quality of life
Polypharmacy – Adverse Reactions
- Not necessarily related to age
- MC from use of multiple meds and number of chronic illnesses present
- The primary purpose of a medication may also be the source of an adverse drug reaction
approx. 14 million hospitalizations occur each year in elderly patients
what two medications are responsible for 2/3 of all medication related hospitalizations
- Anticoagulants (Warfarin)
- hyperglycemics (insulin)
narrow TI drugs
- digoxin
- warfarin
- lithium
- theophylline
- cyclosporine
- tacrolimus
- gentamicin
wide TI durgs
- ibuprofen
- acetaminophen
- antihistamines
- most abx
- BB
- multivitamins
- proton pump inhibitors
what is the term for Unwanted effects of drugs at normal dosage and use
adverse drug reaction
An injury/harm resulting from the use of a pharmacologic agent
what is this adverse reaction term?
Adverse Drug Event
Bradycardia leading to syncope with B-blocker use
Diarrhea related to abx use
Bleeding associated with anticoagulants
are all examples of what type of adverse reaction?
adverse drug reaction
- Adverse drug reaction
- Unintentional overdose
- Withdrawal reaction after abrupt discontinuation
are all examples of what type of adverse reaction?
adverse drug event
how does polypharmacy cause adverse reactions to the metabolism?
-
Inhibition of the P450 system (MC)
- Inhibition of P450 slows metabolism of atorvastatin leading to toxic levels of statin resulting in liver dysfunction, myalgias, and rhabdomyolysis -
Induction of the P450 system
- Results in rapid clearance and decreased effectiveness of drugs that are metabolized by P450
how does polypharmacy contribute to drug-disease interactions?
Underlying disease increases susceptibility to unwanted physiologic effects of a drug
Pt has multiple health care providers
what is this condition? how much does an additional prescriber increase the risk of an adverse drug reaction?
poly-provider syndrome
Each additional prescriber = 29% increase in adverse drug reactions
prevention for poly-providers
- Limit the number of providers prescribing to one patient
- Limit the number of pharmacies (should only have 1)
- Use electronic prescribing (e-scribe)
- Helps keep track of prescriptions
- Some have a drug-drug interaction checker
- Alerts provider to drug interactions before submitting
What is the term that describe the practice of pharmacotherapy in older adults is similar to the practice of pharmacotherapy in younger adults?
Geriatric Pharmacotherapy
Requires an understanding of:
Drug indications
Dosing
Adverse reactions
Drug–drug interactions
what equation can be used to guide drug dosage levels in the geriatric population in terms of creatinine clearance?
cockcroft-gault equation
Why should you be weary of following serum creatine levels?
Serum creatinine levels often remain within normal limits despite a decrease in GFR
older people typically have less muscle mass and are physically less active than younger adults and thus produce less creatinine
what are the Tools to help providers avoid misuse/overuse/underuse of prescription drugs in older adults
(4)
- The Brown Bag Medication Review - Patient to bring medications with them if possible
- AGS Beers Criteria® - updated in 2019
- STOPP - Screening Tool of Older Person’s Prescriptions
- START – Screening Tool to Alert providers to Right Treatment
An expert reviewed list of medications that should be avoided or used with caution in geriatric patients
which geriatric pharmacotherapy criteria is this?
AGS Beers Criteria
Five categories of drugs in AGS Beers Criteria
Drugs to avoid in most older patients
Drugs to avoid in patients with specific health conditions
Drugs to avoid in combination with other treatments due to concern for drug-drug interactions
Drugs to use with caution because of risk of harmful side effects
Drugs to dose differ
what medication is MC implicated in ER visits and hospitalizations for adverse drug reaction
Benefits of stroke prevention in A.Fib and for tx of VTE outweigh risk of hemorrhage for most patients
warfarin
Older age is associated with increased risk of drug-induced hypoglycemia
2nd most common cause of adverse drug reaction for ER visits
what is this drug?
effects?
insulin
Factors that contribute to hypoglycemia
Diminished renal function
Medications that interact with insulin’s effects
Impaired cognitive function
which type of insulin has less risk of hypoglycemia? increased risk?
LA basal insulins - less
sliding-scale insulin - increased
AVOID in elderly patients (if possible)
risks of LA sulfonylureas
All have potential to cause hypoglycemia
Risk is greater in older adults due to decreased drug clearance = Results in accumulation of the drug
what is the preferred drug in LA sulonylureas? what do you avoid?
Glipizide
glyburide
cautions w/ digoxin
- Very narrow therapeutic window - toxicity common
- Impaired renal function and drug-drug interactions lead to elevated serum digoxin levels
- sx of toxicity: fatigue, confusion, GI disturbances
- Monitor serum levels
Potential risks in older adults with NSAIDs
- Peptic ulcer disease
- Renal impairment
- Exacerbates HTN
- Promotes fluid retention
NSAIDs are CI in who/what?
- Heart failure
- Renal dysfunction
- High risk of peptic ulcer induced GI bleeding
what must you do with ASA and NSAIDs if both must be used
- Maximize the time between taking cardioprotective ASA and NSAID
- Take ASA upon awakening, NSAID at least 2 hours later
Alternatives with NSAIDs
- acetaminophen (Tylenol)
- diclofenac gel (Voltaren)
- Topical NSAID with relatively minimal systemic absorption
- Follow up in 2-4 weeks after starting NSAID to evaluate for renal dysfunction, fluid retention, BP elevation
If you must administer NSAIDS amongst the elderly population what should you do to minimize adverse effects
Use at the lowest dose, for the shortest duration possible
Co-administer PPI
Take with food
cautions with opioids
Psychomotor impairment
Increased risk of delirium
impaired gait/falls
sedation
N/V/C
Respiratory depression
Central sleep apnea
antipsychotics in dementia is associated with increased likelihood/risk of:
- MI, stroke, VTE
- Falls, fractures
- Mortality
When deemed necessary to use:
- Discuss benefits and risks with family / caregiver
- Document discussion
- Use for minimum duration of therapy
Complications of nonadherence
Inadequate disease control
Increased ER visits and hospitalizations
Increased health care costs
Higher mortality
Predictors of nonadherence include
- Asymptomatic disease
- Medication side effects
- Inadequate follow-up
- Lack of patient understanding of the value of treatment
- poor patient education
- poor provider–patient relationship
- low literacy
- poor hearing, cognitive impairments - Missed appointments and transportation difficulties
- Complicated dosing regimens
- Polypharmacy
- Financial hardships
How do you improve adherence in geriatric pharmacotherapy
- Patient education!!!
- Review side effect profiles and compliance at EVERY visit
- Consider financial implications of treatment regimens
- Consider dosing regimens
Geriatric Pharmacotherapy Cost Burden
- Hypothetical patient with COPD, DMT2, HTN, osteoporosis, osteoarthritis
- Guidelines for management could require up to 12 medications with multiple daily dosing regimens
- Average monthly cost of recommended medications in this patient $406/month
