Principles of Drug Utilization Flashcards
Questions to consider about how patients perceive medication
- What is your patient’s values regarding
medical treatment? - What benefit/outcome are they seeking?
- What benefit/outcome does evidence
demonstrate the medication has for the
given illness/disease you propose to
treat? - Should pills be “1st line”?
- Can they afford it?
NNT and NNH formulas
NNT - Number needed to treat
NNT = 1/ARR
NNT - Number needed to harm
NNH = 1/ARI
Four stages of life in relation to medications
Fetus
Neonate and Infant
Adult
Elderly
A _____ is an agent that can
cause malformations in a
developing fetus.
teratogen
Factor that allow drugs to cross the
placenta:
- Lipophilic drugs
- Smaller drugs
- Free drugs not bound to plasma proteins
Fetus are deficient in which enzymes?
CYP450
What happens if teratogen exposure is within the first 14 days of fetus?
All or none, results in death or no effect.
What happens if teratogen exposure occurs between 14-60 days of fetus?
Exposure at this stage leads to death of fetus or significant malformations
What happens if teratogen exposure to fetus occurs Day 60 onward:
Does not result in malformation but interfere with function of
organ. Example: ACE inhibitors can cause renal failure in infants.
The Neonatal period is from birth to ____ weeks of age
4
Neonates have differences in their pharmacokinetics, including:
- Absorption: Reduced peristalsis, Higher pH
- Distribution: Increased blood volume, Lower levels of plasma proteins, Blood flow varies so intramuscular injection may not work
- Metabolism: Not born with CYP450 enzyme but develop them over the first few
weeks-months - Excretion: Renal function is reduced in the 1st year of life. Full term babies only
have 30% of normal GFR, Renal tubular secretion is not fully developed.
Factor that allow drugs to enter into the breast milk:
- Smaller molecules can cross more easily
- Lipophilic drugs can cross more easily
- pH of blood and milk
- Breast milk has a lower pH than plasma; therefore alkaline drugs, once they
reach the milk, become ionized and are trapped in the breast milk - Drugs bound to plasma proteins cannot pass into the breast milk
The ____ stage of life should be considered the reference with which all others are compared for medications
adult
How are pharmacokinetics different for the elderly?
- Absorption: Higher gastric pH, Delayed gastric emptying
- Distribution: Low blood volume, Hydrophilic drugs have a higher plasma concentration, Higher body fat, Lipophilic drugs have a lower concentration
- Metabolism: Impaired hepatic metabolic function, Due to reduction in liver mass, hepatic blood flow, and phase 1 enzymes
- Excretion: Some may have declining renal function
Most important factors influencing elderly use of drugs:
- Polypharmacy: Elderly far more likely to be taking multiple medications, predisposing
them to drug interactions - Health: More likely to have kidney or liver disease which will decrease the ability
to excrete drugs - Adherence More likely to have cognitive deficits and live alone
