Pharmacology I Chapter 3 Life Span Considerations

Pharmacology IChapter 3

Life Span Considerations

Drug Therapy during Pregnancy & Lactation

• First trimester = greatest danger of drug-induced fetal development defects• Third trimester = drug transfer to fetus most likely– Enhanced blood flow to fetus

• Fetus is exposed to same medications as mother– Not all drugs cross placental barrier– Review Pregnancy Safety Categories(A-X) **

Drug Therapy during Pregnancy & Lactation

• Breast-fed infants also at risk for drug exposure– Many drugs easily cross into breast milk

• Decision to continue drug during lactation based on risk/benefit ratio

• Certain illnesses require medication during pregnancy/lactation– HTN– Diabetes– Epilepsy– Infection

Drug Therapy for Infants and Children

• Neonate = newborn• Infant = under 1 year• Child = 1-12 years• Pharmacodynamics altered due to immature organ

function• Certain drugs are contraindicated during growth

periods (may delay or alter growth)• Example: tetracycline may permanently discolor teeth corticosteroids inhibit growth - newborns

Drug Therapy for Infant Children

• Drug dosage is SIGNIFICANTLY different from an adult (both rx and OTC)– Should be based on ideal body weight if obese

• Drug dosage must be based on height and weight– For child < 18 years – Ideal body weight vs. actual body weight ??– > 32% children are overweight (2-19)– Limited studies on children re: dosage and weight– Using IBW on obese child can lead to subtherapeutic dose

w/ certain meds– Prescriber must consider pharmacokinetics !!

Drug Therapy for Children• Penicillin

– unknown• Cephalosporins

– Actual body weight• Digoxin

– Ideal body weight• Narcotics

– Ideal body weight• Dilantin

– Actual body weight for loading dose– Ideal body weight for maintenance doses

• 1 kilogram (kg) = 2.2 pounds (lb)

• Example: Infant >3 mos = 15 lbs. = 200mg Child = 40 lbs. = 1200 mg Adult = >40kg = 1500-2000mg

220 lbs. is equivalent to ____________ kg ?

• Convert 88 lb. to kg ___________________

• Convert 60 kg. to lb ___________________

Drug Therapy for the Elderly• Elderly = Geriatric = Older Adult• Adult >65• 13% of population• Advanced health care/technology– Ability to prolong life

• Growing elderly population• Life expectancy = 78– Will increase to 82 by 2030

Drug Therapy for the Elderly• 30% of prescription drugs

– antihypertensives, cardiac, insulin• 40% of OTC drugs

– analgesics, laxatives, antacids– 30-50% use laxatives

• Polypharmacy– 1/3 elderly take 8 drugs per day– many take >15– Average 2-4 OTC drugs/day

• Financial concerns– pill splitting, skipped doses

• Noncompliance– 40%– Associated w/increased hospitalization

Drug Therapy for the Elderly• Lack of understanding– Medication errors

• Visual ability• Timing of medications• Memory issues• Arthritic, weak hands• Illiteracy• Lack of support system

– Multiple prescribers– Multiple pharmacies

• 1 pharmacy preferred– Drug interactions

• OTC• Herbals

Drug Therapy for the Elderly: Physiologic Changes

• Cardiovascular– Decreased CO = decreased absorption – Decreased blood flow = decreased absorption

• Gastrointestinal– Increased pH (stomach) = altered absorption– Decreased peristalsis = delayed gastric emptying

• Hepatic (liver)– Decreased blood flow = decreased metabolism– Decreased enzyme production = decreased metabolism

• Renal (kidney)– Decreased blood flow = decreased excretion– Decreased kidney function = decreased excretion

Drug Therapy for the Elderly: Pharmacokinetics• Absorption– Decreased gastric acid secretion

• Lower gastric pH, may inhibit absorption of certain meds– Decline in smooth muscle tone

• Delayed gastric emptying• Decreased peristalsis

– Decreased CO leads to decreased blood flow to GI tract• 40-50% decreased flow to GI tract

– Absorptive surface area decreased• Flattening of intestinal villi

Drug Therapy for the Elderly• Distribution– Less body water• Less dilution of drug in blood

– Less muscle mass, more adipose tissue• Drugs stored in adipose tissue have longer duration in

body– Low albumin level (low protein)• Protein bound drugs will compete for protein

molecules• Unbound drug concentrations increase

Drug Therapy for the Elderly• Metabolism– Declines w/ age– Liver loses mass, less blood flow– Decreased ability to metabolize drugs

• Prolonged half-life– Dosage adjustments necessary

• Excretion– Delayed due to decline in renal function (GFR)– Kidney function must be monitored closely– Dosage adjustments necessary

Drug Therapy for the Elderly

• Which of the following age groups is most likely to

experience dangerous effects from medications :

a. Infantsb. Childrenc. Adultsd. Elderly

Drug Therapy for the Elderly: Dosage Considerations

• Adjustment of dosage needed– Decreased body weight• Decreased muscle mass

– Decreased organ function• Heart, kidney, liver

– Elderly have increased sensitivity to CNS depressants• Anxiety meds, antidepressants, sleeping pills, etc.

Drug Therapy for the Elderly: Polypharmacy

• Multiple illnesses• Average older adult (1 in 3) takes 8 meds per

day• Increased possibility of drug interactions– Anticoagulants, antidepressants, diuretics,

antihypertensive, antacids• Increased possibility of drug-food interactions– Review p. 212 Eliopoulos, table 18.2– Warfarin (Coumadin) – decreased effect w/ high

Vitamin K foods (green leafy vegetables)

Drug Therapy for the Elderly: Problematic Meds

• Narcotics– Confusion, urinary retention, constipation, fall risk

• NSAIDS– Edema, gastric ulceration, renal toxicity

• Antidepressants– Sedation, urinary retention

• CNS depressants– Sedation, weakness, confusion, fall risk

• Diuretics– Dehydration, weakness

Drug Therapy for the Elderly

• Nursing Diagnoses– Risk for injury related to adverse medication

effects– Knowledge deficit related to ……

Drug Therapy for the Elderly:Patient Education

• Encourage patients to carry a list of all meds – Rx and OTC

• Inform patients to check w/ Physician prior to mixing Rx meds and OTC meds !

• Encourage patients to use 1 pharmacy• Educate pt. on names of medications, indications, dosage,

schedule– Verbal & Written

• Teach patients about potential adverse effects & interactions• Remind pt. that adverse effects can occur at any time, even

after long period of use

Drug Therapy for the Elderly: Patient Education

• Teach pt. – DO NOT take other medications within 2 hours of antacids

• Encourage pt. to ask questions to increase level of understanding

• Encourage pt. w/ visual deficit/illiteracy to use color coded med. bottles, labels w/ large print

• Teach pt. to ask for “easy to remove caps” and “pre-split pills”

• Home health – check and review meds @ each visit– Ongoing pt. education

Drug Therapy for the Elderly: Tips for Safe Drug Use

• Pill boxes – Prefilled– Containers with timer (beeps)

• Color-coded medication bottles• Large print labels• Magnifying glasses• “Easy open” caps• Pill cutters– Pharmacist can also cut pills

• http://www.youtube.com/watch?v=R4jqhnUTWvA

• Right click, open hyperlink