Therapeutics in Pregnancy Flashcards
do the pharmacokinetics of drugs change during pregnancy
yes
pharmacokinetics changes of drugs during pregnancy widely includes
- absorption: oral; IM/SC/transdermal
- distribution
- metabolism
- excretion: renal; hepatobiliary
(ADME)
oral absorption has what pharmacokinetic change in pregnancy
tends to decrease
why does oral absorption tend to decrease as a pharmacokinetic change in pregnancy
- delayed gastric emptying due to progesterone (smooth muscle relaxant)
- reduction in gut motility due to physical effect of uterus
- decreased gastric acid production-> increases gut pH -> variable effects on drug absorption
- nausea and vomiting that may occur from morning sickness
how is oral absorption decrease attenuated in some cases
increases in gastrointestinal blood flow
why does IM/SC/transdermal absorption tend to increase as a pharmacokinetic change in pregnancy
- there is increased regional blood flow
IM/SC/transdermal absorption has what pharmacokinetic change in pregnancy
tends to increase
some significant changes in distribution that occur during pregnancy result in which - decreased or increased volume of distribution of drugs?
increased volume of distribution
what do the increased distributions of volume affect in medication administration
in general, greater dosage of drug required to achieve a therapeutic effect
what happens to total plasma volume throughout pregnancy
- increases
- increased total body water (increase total plasma volume)
-> affects serum protein
what drugs does increased body fat from pregnancy increase the volume of distribution for
lipophilic drugs
describe how can increase unbound fraction of medications -> greater therapeutic effect for a given dose in some medications
- decreased serum protein (dilutional)
- serum proteins bind drugs in bloodstream => more free drug in bloodstream
- can result in greater therapeutic effect for a given dose in pregnant vs non pregnant
what is volume of distribution in pharmacokinetics
distribution of a drug within the body relative to its concentration in the bloodstream
drug distributes more extensively throughout the body beyond the bloodstream. It suggests that the drug is distributed into tissues and organs beyond the bloodstream
more widely distributed within the body’s compartments
what changes in pregnancy lead to decreased serum protein
- serum protein is protein levels in blood serum
- during pregnancy plasma volume increases which has diluting effect on serum protein
how does metabolism of drug change during pregnancy
drug clearance may be increased or decreased based on the particular metabolic pathway