How Do Endocrine Prostaglandins Work?

Endocrine prostaglandin (PG) analogs produced synthetically are used as medications to induce labor or abortion and treat postpartum hemorrhage and gastric bleeding. PGs are a group of lipids released by the immune cells at the site of tissue damage or infection to control inflammation and reduce further damage to the tissue. They also exhibit hormone-like activity. Synthetically produced PGs mimic endogenous PGs.

Carboprost tromethamine is an analog of naturally occurring PG F2 alpha and activates PG F receptor on the smooth muscle causing smooth muscle contractions. This drug stimulates contractions of the uterus and is used for expulsion of fetal material and to induce abortion or treat postpartum hemorrhage caused by atonic uterus.

Dinoprostone is a synthetically produced PGE2. It relaxes cervical smooth muscle and stimulates uterine contractions. It is used to induce labor or abortion. Its exact mechanism of action is unclear; it is suggested that it increases intracellular calcium leading to contractions. However, the mechanism of cervical dilation is yet to be studied.

Misoprostol is a synthetic PG E analog that inhibits gastric acid secretion and protects the gastric mucosa. It also reduces fat malabsorption, possibly by stimulating duodenal bicarbonate production. Misoprostol binds to smooth muscle cells in the uterine lining to increase the strength and frequency of contractions and degrade collagen and reduce cervical tone.

Endocrine PGs are available as intramuscular injections, oral tablets, or vaginal suppository and are used for:

• Abortion
• Induction of labor
• Cervical ripening
• Pregnancy termination
• Refractory postpartum uterine bleeding
• Prophylaxis for nonsteroidal anti-inflammatory drug-induced ulcer

Side effects of endocrine PGs may include:

• Injection site reactions
• Nausea and vomiting
• Diarrhea
• Dizziness
• Drowsiness
• Sleep disturbance
• Fatigue
• Headache
• Vertigo (spinning sensation)
• Weakness
• Upper respiratory tract infections
• Fever and chills
• Muscle and joint pains
• Chest pain
• Arrhythmia (irregular heartbeats)
• Hypertension
• Urinary tract infections
• Anxiety
• Blurred vision
• Anaphylaxis (life-threatening allergic reactions)

Gynecological side effects of endocrine PGs may include:

• Uterine rupture
• Uterine bleeding
• Retained placental fragment
• Endometriosis
• Vaginitis
• Vulvitis
• Postpartum disseminated intravascular coagulation
• Premature rupture of membranes
• Hypertonic uterine dysfunction with or without fetal distress
• Abnormal uterine contractions

The information contained herein is not intended to cover all possible side effects, precautions, warnings, drug interactions, allergic reactions, or adverse effects. Check with your doctor or pharmacist to make sure these drugs do not cause any harm when you take them along with other medicines. Never stop taking your medication and never change your dose or frequency without consulting your doctor.

Generic and brand names of endocrine PG drugs include:

• Carboprost tromethamine
• Cervidil
• Cytotec
• Dinoprostone
• Hemabate
• Misodel
• Misoprostol
• Misoprostol vaginal
• Prepidil
• Prostaglandin E2
• Prostin E2