Targeted Pharmacology Flashcards
Historically what has been the protective barrier for the fetus?
uterus
What drug was prescribed in the 1960s that left children with developmental abnormalities?
Thalidomide
Prescribed for pregnant females for anxiety or morning sicknesss
What drug produced gray baby syndrome?
choramphenical
drug is cleared thrlough liver and kidneys
What would sulfonamide cause?
kernicterus-build of bilirubin
What is increased in pregnant women?
7
Blood flow to the skin
pH
Nausea and Vomiting
Blood volume (causes drug concentration in serum to decrease)
Water content of skin
Fat tissue
Renal blood flow/GFR/faster elimination
What is decreased in pregnant women?
4
Gastric motility
Gastric Acid secretions (causes increased pH which makes it easier for drugs of a more basic nature to get absorbed and harder for drugs of a more acidic nature to get absorbed)
Albumin concentration
Drug concentration in the serum
Why is nausea and vomiting a risk factor for pregnant women?
they are likely to not absorb an adequate amount of nutrients
How much does the blood volume increase?
30-50%
Why is the serum concentration reduced in pregnant women?
its diluted. An example is phenytoin. you have the same amounts of drug but in more volume
Why does increase in adipose composition affect drug activity?
reduced serum drug concentrations of hydrophobic drugs
What does reduced albumin concentration cause?
Since there is not as many proteins to bind to there is increased levels of drugs in the blood (increased serum levels)
More free phenytoin to be excreted and working on the body
How do progesterone levels relate to CYP enzyme activity?
Induce or inhibit the CYP enzyme. So if CYP enzymes are induced then there will be less drug in the blood. If they are inhibited there will be less drug in the blood.
(totally dependant on the person, and specifically their progesterone levels)
How is elimination affected during pregnancy?
Increased renal blood flow
increased GFR
Increased urination
What are the factors that affect medicaiton distribution across the placenta?
- Lipophilic, hydrophobic, non-ionized
- Molecular size
- Osmotic gradient
- Protein binding affinity
Describe issues with fetal drug exposure and the liver?
Fetal hepatic metabolism develops slowly- mother can clear it quickly but the child won’t be able to
When are the critical periods of development in the fetus and how does this relate to drug exposure?
critical period is usually during first trimeter
Some meds are considered safer during certain trimesters
What drugs do we want to consider for labor in the final trimester?
bleeding during labor
Anticoagulants and antiplatelets
Risk Category A what kind of risk?
- Remote possibility of fetal harm
- No risk of fetal harm demonstrated in controlled trials
Risk Category B what kind of risk?
- Animal studies have no demonstrated fetal harm,
- human studies have not been conducted
OR
- Animal studies have demonstrated potential fetal harm,
- but controlled human trials have been done without evidence of harm
Risk Category C what kind of risk?
- Animal studies have demonstrated potential fetal harm,
- but there are no controlled trials to confirm the event in humans
OR
No animal or human studies are available
Risk Category D what kind of risk?
Evidence of fetal risk has been demonstrated in humans, but use may be justified in some cases based on benefit:risk (benefit risk ratio)
Category X: Teratogens
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NEVER USE:
- Significant fetal harm shown in studies with animals or humans
- Significant functional or structural fetal harm
- Contraindicated in women of childbearing age & throughout pregnancy
- Risk of use clearly outweighs any potential benefit
When treating pregnant women how do we treat them first?
3
- Non-pharmacologic strategies- use first
- Minimal effective dose for least amount of time
- If alternative medications are available use the agent with the best safety profil first
Regarding pregnancy pharmacokinetics, which of the follow is true?
Pregnant patients have:
- Increased gastric motility
- Decreased water content of skin
- Decreased blood flow
- Increased blood volume
Increased blood volume by 30-50%
Benefits for mother during lactation (why you should breast feed!)
3
- Post-partum depression
- hypertension
- epilepsy
What does the rate and extent of passive diffusion depend on?
5
Physical properties of the drug:
- lipophilic, hydrophobic and nonionized
- Degree of ionization
- the pH of breast milk is around 7-7.2 (serum of 7.4)
- drug with high pKa = ion trapping - molecular size
- Osmotic gradient
- protein binding affinity
Maternal factors that you should consider while breastfeeding and whether a drug should be takem or not?
4
Blood flow to the breast
Mammary tissue composition
Milk composition
Rate of milk production
How much of the drug does the infant get from the maternal dose?
1-2%