Pharmacological Effect

Misoprostol is a synthetic analogue of prostaglandin E with antisecretory properties. When taken orally, it reduces hydrochloric acid secretion, stimulates bicarbonate and mucus production, and protects internal organ cells. It enhances gastric mucosal stability, preventing erosions and ulcers, and aids in the healing of peptic ulcers. The effects start within 30 minutes of administration and last around 3 hours.

Indications for Use

Misoprostol is recommended for the following conditions:

• Prevention of gastric ulcers linked to NSAID use.

• Treatment of duodenal ulcer exacerbation.

• Stomach ulcers.

• Early-stage abortion (up to 42 days), when used with Mifepristone.

Mechanism of Action

Misoprostol has a mild stimulating effect on gastrointestinal smooth muscles and acts as a catalyst for uterine contractions. It relaxes the cervix, making its dilation easier. This increases uterine tone, which can lead to a miscarriage.

The drug does not significantly affect prolactin, gonadotropins, thyroid hormones, growth hormones, thyroxine, cortisol, platelet aggregation, pulmonary function, or the cardiovascular system.

Contraindications

Misoprostol must not be used in the following cases:

• Pregnancy, unless intended for abortion (due to its teratogenic effects).

• Suspected ectopic pregnancy.

• Hypersensitivity to misoprostol or other prostaglandins.

• Lactation.

• Children and adolescents under 18 years old.

Side Effects

Gastrointestinal: Abdominal pain, nausea, vomiting, diarrhea (11-40%), constipation (1.1%), flatulence (2.9%).

Reproductive system: Irregular menstruation, dysmenorrhea, heavy menstrual bleeding, postmenopausal spotting, uterine cramping.

Allergic reactions: Skin rash, itching, anaphylaxis, angioedema.

Other: Dizziness (2.4%), headache, fatigue, chills, fever, changes in body weight, rare seizures in pre- and postmenopausal women.

Dosage and Administration

Misoprostol is taken orally with water. The dosage depends on the medical condition:

• Gastric ulcer prevention & treatment: 200 mcg taken 2-4 times daily (last dose before bed), with a maximum of 800 mcg per day. If poorly tolerated, the single dose may be reduced to 100 mcg. For renal failure, the dosage is cut by 50%.

• Abortion (with Mifepristone): 400 mcg of misoprostol 36–48 hours after mifepristone.

Overdose Symptoms

• Drowsiness, lethargy.

• Tremors, convulsions.

• Shortness of breath.

• Severe abdominal pain.

• Diarrhea.

• Fever.

• Irregular heartbeat.

• Low blood pressure.

Drug Interactions

• Antacids may lower misoprostolic acid levels (though clinically insignificant).

• Magnesium-containing antacids can increase diarrhea caused by misoprostol.

• Rifampicin, isoniazid, anticonvulsants, antidepressants, cimetidine, aspirin, indomethacin, and phenobarbital-based drugs lower misoprostol levels in the bloodstream.

• Avoid aspirin and NSAIDs for at least one week after taking misoprostol.

• Smoking more than 10 cigarettes per day reduces misoprostol levels.

Precautions

• Misoprostol should always be combined with Mifepristone for medical abortion.

• Administration should be supervised in a medical facility with access to emergency care.

• Patients should be informed about its effects and potential side effects before use.

• Patients must remain under observation for 4-6 hours after administration in case of complications like excessive bleeding.

• Rhesus incompatibility prevention measures should be taken.

Post-Abortion Monitoring

• 80% of abortions occur within 6 hours, while 10% may take up to a week.

• A follow-up examination 8-15 days post-abortion is mandatory.

• If abortion is incomplete after 10-14 days, vacuum aspiration is required.

Storage Conditions

Store in a cool, dry place away from light at a temperature below 25°C.

Shelf Life

24 months.