misoprostol
Cytotec

Available forms
Available by prescription only
Tablets: 100 mcg, 200 mcg

Indications and dosages
 Prevention of gastric ulcer induced by NSAIDs. Adults: 200 mcg P.O. q.i.d. with meals and h.s. Reduce dosage to 100 mcg P.O. q.i.d. in patients who can’t tolerate this dosage.
 Duodenal or gastric ulcer ◇. Adults: 100 to 200 mcg P.O. q.i.d. with meals and h.s. for 4 to 8 weeks.

Pharmacodynamics
Antiulcer action: Misoprostol enhances the production of gastric mucus and bicarbonate and decreases basal, nocturnal, and stimulated gastric acid secretion.

Pharmacokinetics
Absorption: Rapidly absorbed after oral use.
Distribution: Less than 90% bound to plasma proteins.
Metabolism: Rapidly de-esterified to misoprostol acid, the biologically active metabolite. The de-esterified metabolite undergoes further oxidation in several body tissues.
Excretion: About 15% of an oral dose appears in the feces; the balance is excreted in urine. Terminal half-life is 20 to 40 minutes.

Contraindications and precautions
Contraindicated in pregnant women using cytotec to reduce the risk of NSAID-induced stomach ulcers, in breast-feeding women, and in patients allergic to prostaglandins. Uterine rupture may occur if drug is used intravaginally in pregnant women to induce labor or induce abortion beyond the first trimester of pregnancy. Uterine rupture is associated with certain risk factors, including later trimester pregnancies, higher doses of the drug, prior Cesarean delivery, or uterine surgery, or five or more previous pregnancies. Uterine perforation may occur if combined vaginal and oral therapy is used to induce abortion in pregnant women.

Interactions
None significant.

Adverse reactions
CNS: headache.
GI: diarrhea, abdominal pain, nausea, flatulence, dyspepsia, vomiting, constipation.
GU: hypermenorrhea, dysmenorrhea, spotting, cramps, menstrual disorders, postmenopausal bleeding.

Effects on lab test results
None reported.

Overdose and treatment
There has been little clinical experience with overdose. Cumulative daily doses of 1,600 mcg have been administered with only minor GI discomfort noted.
 Treatment should be supportive.

Special considerations
 ALERT Don’t confuse misoprostol (Cytotec) with mifepristone (Mifeprex).
• Drug has been used for treatment and prophylaxis of reflux esophagitis, alcohol-induced gastritis, hemorrhagic gastritis, fat malabsorption in cystic fibrosis, and NSAID-induced nephropathy.
• Don’t prescribe misoprostol for a woman of childbearing age unless she needs NSAID therapy and is at high risk for development of gastric ulcers; is capable of complying with effective contraception practices; has received oral and written warnings about the hazards of therapy, the risk of possible contraception failure, and the hazards this drug would pose to other women of childbearing age who might take it by mistake; and has had a negative serum pregnancy test within 2 weeks before beginning therapy and will begin therapy on the second or third day of her next normal menstrual period.
• Monitor patient for GI distress, especially diarrhea.
• Diarrhea is usually dose-related and develops within the first 2 weeks of therapy. It can be minimized by administering the drug after meals and at bedtime, and by avoiding magnesium-containing antacids.
Pregnant patients
• Pregnant women shouldn’t take misoprostol to reduce the risk of ulcers induced by NSAIDs.
Breast-feeding patients
• Breast-feeding isn’t recommended because of potential for drug-induced diarrhea in infant.
Pediatric patients
• Safety hasn’t been established in children younger than age 18.

Patient education
• Explain importance of not giving drug to anyone else.
• Make sure patient understands that a miscarriage could result if drug is taken by a pregnant woman.
• Advise patient to take drug as prescribed for duration of therapy.

Reactions may be common, uncommon, life-threatening, or COMMON AND LIFE THREATENING.
◆ Canada only
◇ Unlabeled clinical use