N323 - Week 2 (Drug Administration Throughout the Lifespan)

Drug therapy is postponed until pregnancy is over with the exception of serious conditions s.a.. (5)

epilepsy

hypertension/gestational hypertension

gestational diabetes

infections

autoimmune

(fever is also rlly bad !)

... of individuals take at least one medication during pregnancy

90%

Impact of Pregnancy on Absorption of Drugs

hormonal changes affect absorption

-inhaled drugs may be absorbed faster

impact of pregnancy on distribution & metabolism

changes in cardiac output, plasma volume, & regional blood flow change distribution & metabolism

impact of pregnancy on excretion

rate of excretion may increase

Teratogen

A substance, organism, or physical agent to which an embryo or fetus is exposed that causes permanent abnormality in structure or function and causes developmental/physical delays or death

Teratogen EX (3)

Diethylstilbestrol (DES)

Thalidomide (most famous)

Methotrexate

(high blood pressure is also rlly bad for babies..)

Thalidomide & Methotrexate

Thalidomide: can lead to internal organ defects & short limbs

-Methotrexate: amino depressant that leads to face deformations

Preimplantation period

weeks 1 to 2 of first trimester (when most women dont know they're pregnant yet)

-teratogen either causes death of embryo or has no effect

Embryonic period

-weeks 3 to 10

-teratogens have maximum impact

-fetus is developing (organ neogenesis) -> try to avoid medications during this time

Fetal period

weeks 11 to 40 or until birth

-blood flow increases & placental membranes thin, maximizing substance transfer to fetus

-less organ neogenesis (safer to give medications)

Current FDA Pregnancy Category Ratings w/ Examples

A (safe)

B

C

D

X (immediate no)

A Rating

Safe -> has no effect

-prenatal vitamins (not many in this category)

B Rating

Suggest NO harm based on animal studies (basically safe)

-looked at patients over time & saw no harm

-EX.. antibiotics, Tylenol

C Rating

shown adverse effect in animals & don't know abt pregnant women

-not that safe -> try to avoid

D rating

know there's a risk (women do not usually take these)

-UNSAFE

X

known teratogen (immediate no)

-may require pregnancy test prior to administering it

Factors that Affect Drug Exposure Through Lactation (5)

time btwn drug administration & chestfeeding

-parent's use illicit drugs

-amount of drug administered

-amount that reaches fetus tissue

-infant's ability to metabolize drugs

When is the safest time to administer drugs if breastfeeding?

after chestfeeding/pumping

(give more time to excrete it through urine, instead of breast milk)

What drugs should be selected for during lactation?

select for drugs w/ a short half life & w/ a high protein-binding ability

What should be avoided during lactation?

teach parents to avoid alcohol, illicit drugs, tobacco (Can pass through in breast milk)

-avoid drugs w/ long half life

-avoid ALL OTC, herbal, dietary supplements

Pharmacology of Infants

-age range

-priority

-child needs to..

-nurse/parent should be aware of..

-... may be route of choice

birth to first 12 mnths

-Priority is safety (more conservative w/ drugs to babies, it's riskier)

-child needs to ingest all medication; difficult to estimate how much lost if spit out

-nurse/parent should be aware of special procedures for drug administration

-IM may be route of choice

Pharmacology of Toddlers

age range

-teach parents abt..

-give toddler...

-oral drugs can be mixed w/...

-Injections are given at..

period from 1 to 3 yrs

-teach parent abt proper storage of drugs (no toddler access to medications)

-give toddler short, concise explanations (give comfort after)

-can be mixed w/ foods like jam, syrup or fruit puree

-given at specific locations (s.a vastus lateralis)

Pharmacology of Preschoolers

-age range

-description (3)

3 to 5 years of age

-safe storage = out of reach

=can begin to assist w/ medications

-brief explanation followed by administration

Pharmacology of School-Age Children

-age range

-description (4)

btwn 6 & 12 years old

-most children healthy in this period

-offer longer, more detailed explanations

-encourage cooperation

-offer choices when appropriate (give them more autonomy)

Considerations of Administering Drugs to infants & children

gastric & first pass absorption reduced (IM absorption faster & irregular)

-Distribution: more drugs enter brain & less protein-binding

-reduced metabolism & excretion

Neonates & Pediatrics Dosing Pearls (5)

body surface area method (uses the west nomogram)

-always uses weight in kilograms, not pounds

-always use cm, not inches

-body weight dosage calculations: uses mg/kg (or mcg/kg)

Pharmacology of Adolescents

btwn ages 13 & 16 yrs

-need support, approval & presence

What do adolescents need to be educated on? (4)

hazards of tobacco & substance use

-sexual intercourse

-eating disorders

-important medical info (allow time for questions, privacy & control)

Pharmacology of young adults (3)

minimal need for prescription drugs (unless chronic diseases or immune-related conditions are present)

-positive medication compliance

-educate abt substance abuse & treatment of STI

Pharmacology of Middle Aged Adults (3)

health changes begin around 45 yrs of age

-prescribed drugs for stress-related illnesses

-numerous life transitions (may be positive lifestyle changes)

Pharmacology of Older Adults (5)

-commonly take..

-some predictable..

-more adverse..

-reminder..

-maintain..

commonly take multiple medications concurrently (polypharmacy)

-some predictable ailments, but much variability remains

-more adverse drug events in geriatric patients

-reminder aids for administration may be used

-maintain independence & dignity

What is reduced & slowed in older adults?

the process of pharmacokinetics (absorption, distribution, metabolism & excretion)

Less Absorption of Drugs in Older Adults (3)

diminished gastric motility

-decreased blood flow to digestive organs

-increased gastric pH

Less Distribution of Drugs in Older Adults is a result of.. (5)

increased body fat

-reduced plasma level

-less body water

-less albumin produced by liver

-decreased cardiac output

What occurs due to the liver producing less albumin in older adults?

decreased plasma protein-binding ability

-increased levels of free drugs (-> increases potential for drug-drug interaction)

What are causes of reduced metabolism in older adults? (3)

reduced first-pass metabolism rate

-decreased production of liver enzymes

-plasma level elevated

What are results of reduced metabolism in older adults ? (2)

-half life of many drugs increased

-tissue concentration of drugs increased

What are causes of reduced excretion in older adults?

reduced renal blood flow

-reduced glomerular filtration (glomerulus.. where most absorption takes place, some reabsorption occurs in nephron tubes)

-reduced nephron fxn

Polypharmacy

use of multiple drugs, unneeded drugs, overlapping drugs

-(risks: drug interactions)

Prescribing Cascade

drug added to treat side effects of another drug

Drug-Drug interactions

When two drugs counteract each other, may increase or decrease effectiveness

-(remember to think of unaccounted for OTCs and supplements, even grape juice!)