Module 8 - Special Populations Flashcards
Special populations include
- Pregnancy and lactation
- paediatrics
- geriatrics
drugs that are least likely to pass through fetal-placental barrier
- water soluble
- ionized
- bound to plasma proteins (molecules too large)
effects of increased levels of progestins?
- delayed gastric emptying (give more time for absorption to occur)
- increased volume of breath and causes pulmonary vasodilation (higher absorption of inhaled anesthetics only)
changes during pregnancy that affect Absorption
- the blood supply to organs responsible for absorption may change
- increased levels of progestins
- Gastric acidity reduced (affecting ionization of drug)
Changes during pregnancy affecting distribution
- Increased Blood volume can dilute drugs and decrease plasma protein concentrations
- blood flow to uterus and kidneys is increased resulting in higher distribution
- blood flow to skeletal muscle is decreased resulting in lower distribution
- altered lipid levels alter transport and distribution of drugs.
Changes during pregnancy affecting metabolism
Drug metabolism can be increased (drugs become inactive faster) and decreased (drugs become inactive slower) depending on specific CYP450 enzymes.
Changes during pregnancy affecting elimination / excretion
- blood Flow to kidneys increases significantly as pregnancy progresses
- directly increases glomerular filtration rate (GFR) and therefore elimination of MOST drugs is increased (may not be clinically significant)
Considerations: pharmacotherapy during pregnancy
- what is the effect of the CONDITION on the pregnancy? - danger to baby?
- what is the effect of the PREGNANCY on the condition? - Danger to mother?
Def: Teratogens
A substance, organism, or physical agent to which an embryo or fetus is exposed that produces a permanent abnormality on structure or function, causes growth retardation, or results in death.
- extent of significance is very dependent on timing during pregnancy
Examples of teratogens
ACE-I
Statins
Lithium
Some anticonvulsants, antibiotics, etc
- NEVER rely on memory to determine teratogenicity of drug ALWAYS look it up!
FDA pregnancy categories
A - studied in pregnant women and proven to be safe
B - animal studies revealed no harm, BUT no human trial available. OR animal studies showed harm BUT human trials revealed no harm
C - Animal studies revealed har AND no human tails available OR No animal or human studies
D - Studies have revealed harm to fetus but benefits of therapy may outweigh risks in some women
X - studies have confirmed harm and product is contraindicated in pregnancy
Guidlines for pharmacotherapy During Lactation
- administer drug immediately after last feeding to ensure lowest possible levels at next feeding
- Administer drug before longest period between feedings (overnight)
- preference of short half-life drugs with high-protein binding
- consider whether drug is safe to use in infants
- advise pt to check on safety of the drug every time
- avoid natural health product due to lack of reliable information
Drugs that can decrease Milk Production
antihistamines sedating medications some decongestants weight loss medications diuretics high doses of Vitamin B6 Estrogen Nicotine Ergot Alkaloids (for migraines)
MOA: Domperidone
a dopamine antagonist - also increases prolactin levels (indirectly) - off-level used to increase breast milk production
lactation feedback system uses positive feedback - the act of breastfeeding releases more prolactin, which causes more milk production
Adverse effects: Doperidone
Headache, cramping, diarrhea, dry mouth, irregular menstrual bleeding; very small amount passes into breast milk.
Nurse’s role: pregnancy and lactation
Provide objective and non-judgmental information to pt
Act as a resource for information
participate in conversations of benefits vs. risks of treatment
refer patients to appropriate resources
support patient regardless of her decision
Developmental considerations - pediatrics
Organ function is still in development and is responsible for most pharmacokinetic changes
paediatrics (child) includes Newborns - 18 years of age
sites of administration for injections change as age increases and as muscles grow (vaccinations)
doses of drugs are often prescribed as mg/kg or body surface areas (BSA) regimens which require absolute precision in calculations - weight adjusting dose will differ significantly based on age.
Pharmacokinetic Changes in children affecting absorption
GI absorption generally slow in newborn and improves with age
r/t many factors: surface area, degrees of Gi tract profusion, gastric pH, gastric and intestinal motility, biliary function, Gi bacterial flora and dietary contents, first-pass effect - ALL effecting absorption
- generally decrease absorption
Pharmacokinetic Changes in children affecting Distribution
Premature infants have higher membrane permeability
Body composition (more water and less fat) alters distribution - depending on solubility of drug
Lower plasma proteins leads to higher bioavailability of active drug - protein levels increase with age
as heart becomes stronger, cardiac output increases and tissue perfusion is enhanced, increasing distribution
Pharmacokinetic Changes in children affecting metabolism
- CYP450 system does not fully develop until 15-18 years of age
- very low % of adult enzyme activity at birth and increases slowly over time
- each individual enzyme develops at a different rate
- lower liver perfusion also decreases rates of metabolism
- Cumulative effect is generally slower metabolism
Pharmacokinetic Changes in children affecting elimination / excretion
- nephrogenesis complete at 36 wks gestation
- glomerular filtration rate approaches adult levels at 6 months of age
- tubule development (reabsorption and secretion) takes a bit longer
- cumulative effect is generally SLOWER elimination / excretion of drugs than adults
Medication administration in children
Younger children (3-5yrs): brief description followed by QUICK administration older children (5+): can understand longer explanations before administration to ease anxiety
monitoring Adverse effects in children
- can be difficult to monitor due to inability to communicate or describe
- specific drugs that cause specific adverse effects in children (ASA –> eye’s syndrome)
- important to use resources
Nurse’s role: pharmacotherapy in children
- provide comfort - for children and parents
- encourage dafe medication practices at home
- individualize medication administration techniques to each child
- carful monitoring for adverse effects
- encourage adherence at home
- Educate parents.
Def: polypharmacy
a high number of medications (5-10+) which increases the chances of:
- drug-drug and drug-disease interactions
- drug-induced problems
- prescribing cascades
pharmacotherapy consideration in Geriatric patients
In general - physiological processes slow down as age advances
Pharmacokinetic Changes in Geriatrics affecting Absorption
- Gi motility slows, gastric pH increased, decreased blood flow to and from GI tract
- Cumulatively, alterations in absorption are usually clinically insignificant
- important to note that GI tract is the most common site of distress in elderly, likely due to changes in eating habits, nutrition, and elimination.
Pharmacokinetic Changes in Geriatrics affecting distribution
- Lower total body water results in less distribution BUT higher serum concentrations of water soluble drugs
- lipid soluble drugs can accumulate in the higher fat content
- lower plasma protein production leads to higher concentrations of unbound drug
- inefficient BBB leads to higher incidences of cognitive effects
Pharmacokinetic Changes in Geriatrics affecting metabolism
- CYP450 enzymes still active and it is highly controversial whether activity is significantly reduced
- Lower levels of metabolism likely due to reduced hepatic blood flow, therefore any drug metabolized by liver (regardless of specific enzyme) will potentially have longer half-life
Pharmacokinetic Changes in Geriatrics affecting elimination / excretion
- Renal blood flow, GFR, and tubular functions (reabsorption and secretion) all gradually decline with age
- Serum Creatinune remains to be best marker of GFR, can calculate creatinine clearance to predict drug elimination
Some reasons adherence may be difficult in Geriatric patients?
may be r/t: finances physical limitations visual impairment cognitive decline polypharmacy unpleasant adverse effect
ways to improve adherence in geriatric patients?
- ensure patient understanding
- contacting supportive financial services
- easy-open containers or pill boxes
- simplify regimens
- engage family members or other supports
- schedule adequate follow-up
what medications should NOT be crushed to altered?
- enteric-coated
- Extended release (ER, XR, XL), sustained release (SR) modified release (MR) controlled delivery (CD) long-acting (LA)
- drugs knows to directly irritate esophagus or stomach
- drugs meant for sublingual or buccal administration
- capsule contents should not be crushed
some reasons older adults are at an increased risk for adverse effects?
- polypharmacy
- physiological changes that affect pharmacokinetics and pharmacodynamic of medications
- difficulty to differentiate between an adverse effect and normal aging process
complications around adverse effects in geriatric patients
- Advere effect and disease / condition can present differently in a geriatric patient - atypical symptoms, also may not be able to communicate symptoms
what awesome symptoms that medications should be considered the underlying cause of in Geriatric patients?
- rapid weight loss sudden change in mental status dehydration restlessness falls urinary or fluid retention change in bowel habits anorexia Major change in functional status of organ
Potentially inappropriate medications in Geriatrics
Antihistamines Bensodiazapines Digoxin - reduce renal clearance and can cause serious toxicity Muscle relaxants NSAIDs Phenytoin Antipsychotics (both classes) TCAs * exception to every rule - these are just generally inappropriate, not always.
nurse’s role: geriatric patients
- briefly review med list
- follow suggestions that can improve adherence
- assess and monitor for adverse effects
- if possible discard all unused, and expired medications
- periodically question patent about NHP and OTC use
- Suggesting environmental modifications to decrease fall risk
