Pharmacotherapy in obstetrics

Topics of the lecture

1. Introducton2. Medications used during pregnancy – hormones and

neuro-peptide analogues3. Medications used in labor4. Medications used for miscarriage treatment5. Medications used for fetal hypoxia and gestosis

treatment.6. Medications used for treatment of extra-genital

pathology.7. Medications used for treatment of puerperium

diseases.

Introduction Neuro-humoral system of woman is aimed for

keeping uterus’ muscle relaxed during pregnancy. It’s possible because of increasing of blood levels of steroid hormone pregesterone which is “pregnancy pretector”

Both estrogens and proges-terone are increased during pregnancy but proges-terone prevails

Influence of steroid hormones

Progesterone performs its acton on uterus only in case estrogenes are synthesised enough by corpus luteum and placenta

In other case, progesterone looses its relaxing action on uterus’ muscle

Progesterone

Increases level of adenosinmonophosphate (AMP) which ties Са2+ ions and blocks actine-myosine contractions

Progesterone Increases membrane potential of myocyte and

particularly blocks impulses between myocytes Myometrium becomes insensitive to irritatons

myometrium

Progesterone

Since placenta is formed, progesterone is synthesized by it.

Consequently, placental site is more relaxed than the rest of myometrium

Progesterone

Keeps its relaxing action even in case of retention of the part of the placenta inside of the uterus in puerperium.

It can provoke sub-involution of uterus and post-partum bleeding

Influence of steroid hormones

Before labor level of progesterone decreases and estrogenes are rised

Estrogenes take out myometrium block

Influence of steroid hormones

Membranes of myocytes become sensitive to:

oxitocine, prostaglandines, catheholamines , serotonine.

Mechanism of myometrium contractions

Depolarization of membtanesReleasing of Ca2+ Interaction of calcium ions with contractive

proteins.

Mechanism of myometrium contractions

Myometrium has alpha and beta-adrenoreceptors.

Stimulation of alpha-receptors by catheholamines causes uterus contraction

Stimulation of beta-receptors by catheholamines causes uterus relaxation

Mechanism of myometrium contractions

Uterus body contains alpha and beta catheholamines receptors

Lower segment contains choline and serotonine receptors Cervix contains chemo-, baro- and

mechanoreceptors

Uterotonics and tocolytics drugs

Uterotonics increase uterine contractions (oxytocine, prostaglandines, serotonine, kinines, cathecholamines).

Tocolytics decrease uterine contracions (spasmolytics, beta-receptor-stimulating medications, anti-oxytocin drugs).

Oxitocine

It’s a hormone of supra-optic and para-ventricular nuclei of hypothalamus

Transported to pituitary by axons Performs its influence on membranous level

Prostaglandines

Play very big role in preparing to labor and delivery onset.

“Tissue hormones” are made from fatty (lipid) acides

Prostaglandines

Nowadays synthetic analogues of E2 and F2-alpha prostaglantines are popular because of their high activity

E2 medications (dinoprostone, prepidil-gel, 1 mg) prepare cervix for labor (makes it “ripe”)

F2-alpha medications (dinoprost, enzaprost, i.v. 5 mg/ml) cause regular uterine contractions

Prostaglandines

Their administration causes termination of pregnancy in any term

Pharmacotherapy of miscarriage

Spasmolytics: drotaverine (No-spa) 2 ml i.m., papaverine in average doses

Homeopatic medication: Viburcol

Magnesial treatment

MgSO4 25% - 40 ml i.v. soluted in 400 ml of 0.9% NaCl

MagneB6 1 pill 4-6 times daily (200-300 mg of Mg daily),

Tocolysis (after 16 weeks of pregnancy)

Beta-adrenoreceptor agonist: Gynipral (hexoprenalini

sulphatis)

Pills 0.5 mg each 6-12 hrs

I.v. vials 5 mcg

Side effects should be treated by calcium antagonists: verapamil (isoptin) 1 pill (40 mg) 3 times daily

Tocolysis (after 16 weeks of pregnancy)

Calcium-chanel-blocking agents:

Corinfar (nifedipine) 10 mg every 20 min until symptoms of threatening of pre-term labor are resolved

Key points of hormonal therapy of mascarriage

Hormonal medications should be strictly indicated;

Risk/benefit should be assessed thoroughly;

Individual dosage;Prescription after 8 weeks of pregnancy

should be preferred.

Gestagens

Progesterone 10-25 mg daily; Utrogestane 100 mg p.o. per vaginum 2 times

per day (till 27 weeks); Duphastone (didrogesterone) – 40 mg p.o.at

once, then 1 pill (10 mg) 2-3 times daily.

Treatment of post-partum hemorrage

Oxitocine 5-20 IU Methylergometrine — 1 ml i.m.Prostaglandines

Thank You!