Pregnancy & Lactation Flashcards
What will happen to drugs that are renal cleared during pregnancy?
The concentration of renal cleared drugs will decrease cut to the increased maternal plasma volume, cardiac output, and GFR increase by 30-50%
What will happen to fat soluble drugs during pregnancy?
- Distribution of fat soluble drugs may increase
What will happen to drugs that highly bind to proteins in the blood during pregnancy?
Increase in distribution of drugs that are highly protein bound (unbound drugs do not change much in concentration)
What effect does nausea, vomiting and delayed gastric emptying have on drugs during pregnancy?
- Alters the absorption of drugs
- Increased gastric pH will affect absorption of weak acids and bases
- Increased estrogen/progesterone may result in enhanced elimination or accumulation of some drugs
What chemical properties may influence the rate of transfer of drugs across the placenta?
- Lipid solubility
- Electrical change
- Molecular weight
- Degree of protein binding of the drug
What could happen in the first two weeks after conception if exposed to a teratogen?
The “all or nothing” effect. Either the embryo will be destroyed or the embryo will not have any problems at all
What could happen to an embryo if it is exposed to teratogens between 18 and 60 days of pregnancy?
This is the period of organogensis and exposure to teratogen could lead to structural anomalies.
Other problems are: growth retardation, CNS abnormalities and death
Medications associated with teratogenic effects
- Chemo drugs (methotrexate, cyclophosphamide)
- Sex hormones diethylstilbesterol)
- Lithium
- Retinoids
- Thalidomide
- Certain anti-epileptics
- Coumarin derivatives (coumadin)
Category A drugs
These drugs have no risk to the fetus in any trimester
Category B drugs
Animal studies have shown these drugs have no effect on the fetus but they have not been tested on humans
Category C drugs
Animal studies have shown these drugs have an adverse effect on the fetus. No studies done on humans but benefits might outweigh potential risk in certain situations.
Category D drugs
Animal studies have shown these drugs have an adverse effect on the fetus. No studies done on humans but benefits might outweigh potential risk in certain situations.
Category X drugs
Do not use these drugs in pregnancy. Evidence of fetal abnormalities or risk have been found.
What are the pregnancy induced conditions? (9)
- Constipation
- GERD
- N&V
- Gestational diabetes
- HTN
- Thyroid abnormalities
- Thromboembolism
- UTI
- Allergic Rhinitis
Tx for Constipation
- Light exercise
- Dietary fiber
- Fluids
- Supplemental fiber/stool softener if needed
- Can also use osmotic laxatives (polyethylene glycol, lactulose, sorbitol, magnesium and sodium salts)
What should you avoid with constipation?
Castor oil and mineral oil
Tx of GERD
- Antacids
- Aluminum
- Calcium
- Magnesium preparations
- Sucralfate
- H2 blockers (famotidine, ranitidine) are safest.
What should you avoid with GERD?
- Sodium bicarbonate
- Magnesium trisilicate
Tx of N&V
- Frequent, small, bland meals
- Avoid fatty foods
- Pyridoxine (Vit B6)
- Antihistamines (doxylamine)
- Acupressure at point P6 on velar aspect of the wrist
Tx of Gestational Diabetes
- Daily self monitoring required
- Insulin therapy
- Alternatives to insulin: glyburide and metformin (not as well studied as glyburide)
At what glucose levels do you need to start treating gestational diabetes?
FPG- below 90-99
1Hr postprandial- </= 140
2Hr postprandial- below 120-127
Tx of HTN
- Calcium 1 g/day
- Magnesium sulfate is recommended to prevent eclampsia
- Methyldopa, labetalol and CCB are commonly used
What should you avoid in the treatment of HTN during pregnancy?
- ACE
- ARB
- renin inhibitors
- Diazepem
- Phenytoin
What thyroid abnormality can happen to pregnant women?
During pregnancy, there is an increase in thyroid hormone secretion so some women get postpartum thyroiditis
How do you treat postpartum throiditits?
- Most of the time it resolve spontaneously
- Propanolol/labetolol provide symptomatic relief of adrenergic symptoms
Tx of thromboembolism during pregnancy
- Unfractionated heparin
- LMWH (preferred)
How long should you tx thromboembolism during pregnancy?
Should be continued throughout pregnancy and for 6 weeks after delivery
Should you take warfarin for thromboembolism during pregnancy?
NO. Don’t do it.
Tx of UTI during pregnancy
- Cephalexin (usually stick with cephalosporins)
- Nitrofurantoin (not active against proteus species)
What is contraindicated for Tx of UTIs during pregnancy?
- Sulfa drugs (bacterium)
- fluoroquinolones
- tetracycline
First line tx for allergic rhinitis during pregnancy
- intranasal corticosteroids
- nasal cromolyn
- 1st generation antihistamines
What is contraindicated in the tx of allergic rhinitis during pregnancy?
Oral decongestants like sudafed
Purpose of tacolytic agents
To postpone delivery long enough to allow for the maximum effect of antenatal steroid administration
Examples of tacolytic agents
- Beta agonists
- Magnesium
- Ca channel blocker
- NSAIDS
Example of beta agonist
Terbutaline 250-500mg SQ q3-4hrs
Beta agonist side effects
Higher incidence of maternal side effects:
- hypokalemia
- arrhythmias
- hyperglycemia
- hypotension
- Pulmonary edema
Example of CCB
Nifadipine
CCB side effects
- Fewer side effects compared to magnesium and beta agonist
- Hypotensive effect
- Change in uteroplacental blood flow
Example of NSAIDS
Indomethacin
NSAID side effects
Increased rate of premature constriction of the ductus arterioles in infants
Antenatal Corticosteroid Purpose
For fetal lung maturation to prevent RDS
Dosing of antenatal corticosteroids
Betamethasone 12mg IM q24hrs for 2 doses
or
Dexamethasone 6mg IM q12hrs for 4 doses
(given to pregnant mom between 26 and 34 weeks)
What happens to the cervix in the last few weeks of pregnancy?
Softens and thins to facilitate labor
What hormones regulate cervical ripening and labor induction?
Prostaglandins E2 and F2, they increase callagenase activity in the cervix leading to thinning and softening
What are the most common indications for induction?
- Postdatism (beyond 42 wks)
- Pregnancy induced HTN (80%)
Labor Induction Medications
- Postaglandin E1 analogs
- Prostaglandin E2 analog
- Anti-progesterone agent
- oxytocin
Prostaglandin E1 Analog examples
Dinoprostone (prepidil gel or cervidil vaginal insert)
What must you do when giving a prostaglandin E1 analog?
Pt must be attached to a fetal heart rate monitor for the duration of cervidil use and 15 minutes after its removal
Prostaglandin E2 analog
Misoprostol
Side effects of Misoprostol
- Uterine hyperstimulation
- meconium stained amniotic fluid
When is misoprotol contraindicated?
Women with a previous uterine scar because of its a/w uterine rupture
Anti-progesterone agent example
Mifepristone
Oxytocin
- Most commonly used labor induction agent
- Effective in low dose and high dose
Epidural Analgesics
- Used for pain
- Fentanyl
- Bupivacine
Patient controlled epidural analgesics
- Patient controls the amount and timing of anesthetic
- Results in lower total dose of local anesthetic
Regional anesthesia side effects
- Hypotension
- Pruritis
- Inability to void
Epidural side effects
- prolongation of 1st and 2nd stages of labor
- higher number of instrumental deliveries
- maternal fever
Factors affecting drug transfer from maternal blood to breast milk
- degree of protein binding in maternal plasma
- molecular weight
- lipid solubility
- maternal plasma concentration
- drug half life
- drug pH
What is one of the most significant factors in the drug transfer to breast milk?
Degree of protein binding in maternal plasma proteins.
***Highly bound medications transfer in low amounts
Low molecular weight drugs
Passively diffuse into breast milk. However larger molecules are not likely to transfer in large amounts
Lipid solubility of drugs
Higher lipid solubility increases the likely hood of transfer into the breast milk
What type of drugs are the best for lactating mothers?
Drugs with lower oral bioavailability and lower lipid solubility
When should a lactating mother take medication?
- Try to increase the interval of when you take the drug to when you feed as much as possible
- Immediately after breast feeding
What can a lactating mother do during short term drug therapy?
Pump and dump if the medication is not compatible with breast feeding
Mastitis
Inflammation of the breast (infectious or non-infectious)
What is the most common cause of milk stasis?
mastitis
S/S of mastitis
- breast tenderness
- redness
- warmth
- flu like symptoms
Risk factors for mastitis
- breast engorgement
- plugged milk ducts
- cracked nipples
What bacteria is the most common cause of infectious mastitis?
Staph. Aureus
Tx of mastitis
10-14 day antibiotic such as penicillinase resistant penicillins(dicloxacillin) or cephalosporins (cephalexin) and continue breast feeding or pump if you can
Tx of postpartum depression
- First line tx is sertraline
- Paroxetine and nortriptylline are considered second line tx
Non pharmacologic tx of relactation
Nipple stimulation:
- infants nursing
- mechanical pump
- hand
Parmalogix tx of relactation
Metoclopramide stimulates prolactin secretion. Only used if non pharacologic options aren’t effective. (10mg PO 3x daily for 7 to 14 days)
First line pharmacologic tx of relactation
Fenugreek (herbal supplement)
