Yingling - Drug Therapy and Aging Flashcards
Neonates and Infants:
In critical situations, most often drugs are given ___________, but most drugs are given by ___________ routes.
intravascular, extravascular
These conditions associated with altered ______ drug absorption.
Congenital Heart Disease
Respiratory Distress Syndrome
Congestive Heart Failure
Short Bowel Syndrome
Thyroid Disease
oral
Water soluble drugs have a great distribution in neonates and infants. Why?
they are more water than they are muscle
Percent Body Weight that is water:
a. Neonate: 70-75%
b. Premature neonate: 85%
c. Adult: 55%
Percent Body Fat
a. Premature infant: 1%
b. Full-term: 15%
Percent of extracellular water to body weight
a. Neonate: 40%
b. Adult: 20%
Renal Function:
GFR is ________ (higher/lower) in neonates than adults.
GFR is ________ (inc/dec) by 50% during 1st week of life.
GFR attains adult levels between 6-12 months.
lower
increased
Drug Metabolism
- For infants, there is a ________ (inc/dec) in P450 activity but activity increases rapidly.
- Metabolism in neonate is dependent on drug tx or environmental exposure of mother.
- enzyme induction or inhibition in the fetus
- drugs carried in breast milk - Conjugation reactions __________ (increased/diminished) especially glucuronide conjugation.
decrease
diminished
What 2 drugs are displaced by bilirubin?
Phenytoin
Indomethacin
Child born with PDA and need medication to close it
Adverse Side Effects - what drug?
- 30% dec in GFR
- 60% fall in urine flow rate
- variable effects on electrolyte (hyponatremia)
Indomethacin
Renal Effects in Infants
- Digoxin: t1/2 in neonates is 60-170 hr, adults 30-60 hrs
- Furosemide:
- most common diuretic administered
- immature kidney has dec perfusion (receives 5% of cardiac output at birth)
- delayed response to furosemide
the dosing of a child should be calculated on __________.
surface area
Dosages by body weight can under-estimate dose
Goal with the elderly when prescribing drugs must be to prevent _______________ reactions, a noxious or unwanted response that occurs at a dose that usually is therapeutic.
adverse drug reactions
If the response to a drug is an unexpected response of the immune system, it is a ______________ reaction.
hypersensitivity
Functional Changes in the Elderly
- Cardiac: cardiac output declines 1%/yr after the age of _______
-
Renal: GFR declines 0.5%/year after the age of _______
tubular secretion decreases 0.5-1%/year
30
20
Fact.
Type A Reactions: predictable pharmacokinetics and pharmacodynamics
Type B Reactions: unpredictable, Black Box Warnings - life-threatening
Use of __________ lowers absorption of cimetidine, digitalis, tetracycline, phenytoin.
antacids
Decreased gastric acid secretion by parietal cells, raise stomach pH. This results is less absorption of __________ and __________.
ferrous sulfate and ketoconzaole
Vd for lipid soluble drugs is ________ (inc/dec) d/t increased adipose tissue.
This increases t1/2.
Diazepam, Flurazepam, Amiodarone
increased
Vd for water soluble drugs is __________ (inc/dec) d/t decreased total body water (as much as 15%).
Diuretics can magnify effect causing elevated serum levels of drug.
Ethanol, Procainamide, Atendol
decreased
Vd for drugs that bind to muscle is _________ (inc/dec) d/t decreased lean body mass.
Digoxin binds to muscle Na+/K+ ATPase.
decreased
Half-life _________ (inc/dec) for some drugs because of decreased phase I metabolism by P450.
Diazepam
increased
Plasma Protein Binding
- Lower plasma albumin results in an increased free fraction of _________ (acidic/basic) drugs, like Warfarin & Phenytoin.
- Protein binding can be decreased by: renal disease and low protein diets.
- Binding displacement with concomitant use of drugs - Wargarin and acetyl salicylic acid
- Acidic
Name term.
____________ is the measurement of the functional loss of drug per unit of time (ml/kg).
Clearance
True or False: Hepatic Clearance affects both Phase I and Phase II metabolism.
False - decrease in hepatic clearance mostly affects Phase I metabolism, NOT PHASE II.
____________ (what organ) elimination in the elderly is diminished for:
digoxin
penicillin
gentamicin
tobramycin
lithium
tetracycline
1st generation cephalosporins
Renal
Fact: Elderly have decreased muscle mass and lower creatinine production.
Pharmacokinetics or Pharmcodynamics?
Changes in the binding of drug to receptor, receptor number or altered translation of receptor initiated responses.
Elderly:
-dec adrenergic receptor response
-dec effect of B-adrenergic agonists and antagonists (less bradycardia with propanolol)
-inc receptor response to opiates and benzos
(greater sedation with morphine or diazepam)
Pharmacodynamics
Digoxin has lower _______ elimination in the elderly.
Diuretics - watch for ________ and/or ________ depletion.
renal
potassium or magnesium
Psychoactive Drugs
Black Box warning for atypical and typical __________ antagonists in elderly.
____________: worsens orthostatic hypotension
____________: requires renal excretion and dose must be adjusted for renal function.
Dopamine
chlorpromazine
lithium
What class of drugs is used to treat arthritis, pain and inflammation?
-GI Ulceration
- Alter renal function:
- potential to induce Na+ and H20 retention
- dec renal blood flow and GFR
- induce hyperkalemia
- impair action of certain diuretics
- LT use of analgesics can induce papillary necrosis
-Selective COX Inhibitors
NSAIDS
What is the name of the Program for the FDA Medical products reporting system?
Med Watch Program
Fact: Prescription Cascade - drugs for drug side effects.
