Pregnancy Pharm

Absorption of Drug

the movement of a drug from its site of administration into the blood

Distribution of Drug

drug movement from circulation throughout body and tissues

Elimination of Drug

metabolism and excretion

Pharmacological effect of drug leads to clinical response... what are the two possible clinical responses?

toxicity

effectiveness

Pharmacokinetics

the process by which drugs are absorbed, distributed within the body, metabolized, and excreted

Pharmacodynamics

the process by which a medication works on the body

via absorption and distribution

Perinatal

the time and events surrounding birth

How does lipid solubility affect pharmacokinetics? Pertaining to pregnancy

more lipid solubility = more crossing of placenta

What are lipid soluble drugs called?

lipophilic

What is an example of a lipophilic drug?

thiopental

How does ionization of drugs influence pregnancy-related pharmacokinetics?

highly ionized drugs cross the placenta slowly

Is this generally 'good/bad?'

good

you don't generally want drugs to cross the placenta

What are some examples of highly ionized drugs?

succinylcholine

tubocurarine

What are some drugs that are taken for Cesarian sections?

bupivicaine

midazolam

fentantyl/remifentanil

acetaminophen/NSAID

What is bupivicaine used for?

spinal anesthesia

What is midazolam used for?

pre-spinal anesthesia

What is fentanyl used for?

analgesia

What is most ideal about using Remifentanil on pregnant patients?

it has a low risk of crossing the placenta

Essentially, Remifentanil is wanted to influence the ___, not the ___

mother

fetus

What are Acet/NSAIDs used for?

post=operative pain

How does molecular size affect pharmacokinetics? Relate it to pregnancy

larger molecules cross the placenta with more difficulty

smaller molecules cross placenta with less difficulty

How do you measure molecular size?

molecular weight

Drugs with MW of ___ can easily cross the placenta

250-500

Drugs with MW of 500-1000 ___

cross with difficulty

Drugs greater than 1000 ___

can barely cross, if at all

In regards to lipid solubility, ionization, and molecular size, the placenta essentially serves as a ___

barrier

Which anticoagulant is preferred during pregnancy: heparin or warfarin?

heparin

Why?

it barely crosses the placenta

Why is warfarin generally not used during pregnancy? Effects

teratogenic

Why is warfarin generally not used during pregnancy, as compared to heparin? Pharm

smaller

more lipid-soluble

What factor 'aids the placental barrier' in preventing drugs from crossing?

plasma proteins

How?

plasma proteins bind drugs

this will affect the rate of transfer and the amount transferred

However, as a general rule of thumb, if a compound is highly ___ it will not be affected greatly by protein binding

lipid soluble

The placenta serves as a barrier. The placenta also plays a role as a site of ___ of some drugs that pass through it

metabolism

Drugs that cross the placenta enter via the ___

umbilical vein

About 40-60% of umbilical vein flow enters the ___

fetal liver

Is this good/bad, in the case of inappropriate drug consumption on behalf of the mother? And why?

bad

fetal liver will receive these drugs and break them down inside of the fetus

The fetal live metabolizes drugs more (quickly/slowly) than the adult liver

slowly

What does this lead to?

more medication build up in the fetus

more effect... and more adverse effects....

The ___ categorizes drugs based on their pregnancy-associated teratogenic risks

FDA

Teratogen

any factor that can cause a birth defect

Category A

no risk to fetus

Category B

studies indicate no risk to the animal fetus; information for humans is not available

generally considered safe for human use

B can also be ....

animal studies showing adverse effects, but pregnant women (human) show no adverse effects

Category C

adverse effects reported in the animal fetus; information for humans is not available

Category D

there is positive evidence of human fetal risk based on adverse reaction data from investigational or marketing experience or studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risks

When can a category D drug be used? Hint: this is rare

life-threatening situations

serious disease, for which safer drugs cannot be used or are ineffective

Category E

never use this drug on pregnant patients!!!

NO MATTER WHAT

Toxic drug actions depend on the fetus's ___ and ___

stage of development

how long the mom takes the drug for

What is a popular example of a drug that is teratogenic?

Thalidomide

What does taking Thalidomide when pregnant cause?

phocomelia

(limb disorder)

What is probably the most popularly discussed fetal syndrome?

fetal alcohol syndrome

How does a baby get this?

mom drinks alcohol during pregnancy

What are some behavioral symptoms of fetal alcohol syndrome?

hyperactivity, delayed motor development, and intellectual disability

How about physical?

small head, epicanthal folds, flat midface, smooth philtrum, low nasal bridge, small eye openings, short nose, thin upper lip, underdeveloped jaw

If a baby is born very underweight and tiny in size, and the mother took drugs during her pregnancy, you can assume that the mother took one of these two:

nicotine

cocaine

Are there fetal therapeutics that can provide positive effects to/in the developing fetus?

yes

Give a few examples:

corticosteroids —> stim lung dev

Phenobarbital —> induces hepatic enzymes

Digoxin, flecainide, verapamil —> treats fetal cardiac arrhythmias

antivirals —> decreases/eliminated transmission of viruses, such as HSV and HIV, to the fetus

What are some commonly used drugs during pregnancy?

antiemetics

antacids

antihistamines

analgesics

antimicrobials

diuretics

hypnotics

social drugs

Antiemetics are usually taken/most necessary during the ___ of pregnancy

start

What are some examples of drugs that pose significant teratogenic effects and cannot be taken during pregnancy?

Diazepam —> withdrawal effects affecting fetus at birth

Propylthiouracil —> congenital goiter

Tamoxifen —> spont abortion risk

Tetracycline —> discoloration/defects of teeth

Topiramate —> oral cleft

Most drugs taken by a ___ woman are detectable in ___.... Think postpartum

lactating

breast milk

T/F: nursing of a newborn would lead to exposure of the drug in the newborn

true

Which drugs are more likely to accumulate in breast milk?

weak base drugs

Why?

breast milk has a slightly lower pH (6.8) than plasma (7.4)

If a nursing mother needs to take meds, and the drug is relatively safe, the drug should be taken ___ after nursing and ___ before the next feeding

30-60 minutes

3-4 hours

Most ___ are detected in breast milk

antibiotics

___ can sedate the nursing infant, as they are often transmitted by breast milk

Sedatives/Hypnotics

What are some examples of S/H?

barbiturates

diazepam

opioids

ethanol

Are stimulants commonly transmitted via breast milk?

no

but it is definitely possible, especially in high concentrations

What are some examples of stimulants?

nicotine

caffeine

What are some drugs that are fine to be used during lactation?

aspirin

ampicillin

penicillin

thyroxine

How about drugs that are not to be used during lactation?

methadone/heroin

radioactive Iodine

tetracycline

chloramphenicol

diazepam