Pharmacology of Pregnancy and Lactation Flashcards
Physiological changes of pregnancy may alter drug disposition and effect through:
- Direct Effects - ex. Placental transfer
- Indirect Effects - Changes in placental and uterine function
- Even after delivery drugs may affect breastfeeding
Most Common Medications Taken During Pregnancy
Antiemetics
Antibiotics
Analgesics
At least 10% taking drugs with long term effects on CNS
Antidepressants
Anticonvulsants
Antipsychotics
Concerns of Medications during Pregnancy
Teratogenicity Effects ( not only congenital abnormalities but non-birth development such as puberty) Fetal Loss Congenital Malformation Fetal Growth Restriction Preterm Labor
Recently recognized mothers who are ultra-rapid metabolizers of codeine may transfer morphine through breast milk :
to cause neonatal CNS depression and even death
Major physiologic changes during pregnancy alter drug disposition
Absorption and Uptake
Oral absorption and bioavailability not usually affected by pregnancy
Intestinal motility decreases
Gastric emptying only delayed during labor or administration of opioids
Reduced FRC (functional residual capacity)
Increased minute ventilation increases pulmonary uptake of inhalational anesthetic agents
Distribution
Peripheral delivered drugs are delivered more quickly
Onset of IV and inhalational dependant on time course of their cerebral drug concentrations (amount of concentrated drug to brain) A delay in the increase in arterial and brain anesthetic concentration will result from increased peripheral perfusion
Increased peripheral perfusion will increase the return of drug during elimination phase
_____ binding changes more important clinically
Protein
Increased concentrations of free drug (not protein bound) which is offset by
increased clearance (increased GFR)
______ and ____ require monitoring and modification of dose because of changes in protein binding
Theophylline, phenytoin
Most drugs are metabolized in the ____
liver
Rate of metabolism depends on __________
hepatic blood flow
Although CO increases it is not clear if
blood flow to liver increases
Most cytochrome (CYP) P450 isoenzymes ______
increase
drugs Increases Metabolism
Phenytoin
Morphine
MIdazolam
Drugs that Decreases Metabolism
Caffeine
Theophylline
Drugs metabolized by the liver may require __________in dose, depending on the metabolic pathway involved.
increases or decreases
Drugs excreted unchanged by the kidneys often require an ______dose.
increased
No anesthetic drugs have been shown to be teratogenic
true or false
true
There is no know teratogenic risk associated with the use of _______which is preferred mild analgesic and antipyretic during pregnancy
acetaminophen
NSAIDs have been associated with
an increase risk for some birth defects
Aspirin usually avoided in the third trimester because of fetal risk for:
Renal injury
Oligohydramnios
Intrauterine constriction of the ductus arteriosus
Opioids are not considered to have a _______ ____
teratogenic risk
Tramadol has analgesic effects from weak opioid activity and inhibition of _________ and _________uptake Tramadol exposure in early pregnancy was associated with a higher number of spontaneous abortions and it should be avoided in the first trimester
serotonin and norepinephrine
Some studies have suggested that first-trimester exposure to ______ increases the risk for cleft lip with or without cleft palate, neural tube defects, intestinal atresia, and limb defects. Other reports have not suggested an increase rate of congenital abnormalities after fetal exposure to benzodiazepines
diazepam
_____has the highest teratogenic risk followed by _______, _____, and _______.
Valproate, phenytoin, phenobarbitone and topiramate