Overview
DESCRIPTION Misoprostol oral tablets contain either 100 mcg or 200 mcg of misoprostol, a synthetic prostaglandin E1 analog. Misoprostol contains approximately equal amounts of the two diastereomers presented below with their enantiomers indicated by (±): Misoprostol is a water-soluble, viscous liquid.
Mechanism of Action
CLINICAL PHARMACOLOGY Pharmacokinetics Misoprostol is extensively absorbed, and undergoes rapid de-esterification to its free acid, which is responsible for its clinical activity and, unlike the parent compound, is detectable in plasma. The alpha side chain undergoes beta oxidation and the beta side chain undergoes omega oxidation followed by reduction of the ketone to give prostaglandin F analogs. In normal volunteers, misoprostol is rapidly absorbed after oral administration with a Tmax of misoprostol acid of 12 ± 3 minutes and a terminal half-life of 20 to 40 minutes. There is high variability of plasma levels of misoprostol acid between and within studies but mean values after single doses show a linear relationship with dose over the range of 200 to 400 mcg.
Indications
- INDICATIONS AND USAGE Misoprostol is indicated for reducing the risk of NSAID (nonsteroidal anti-inflammatory drugs, including aspirin)–induced gastric ulcers in patients at high risk of complications from gastric ulcer, e.g., the elderly and patients with concomitant debilitating disease, as well as patients at high risk of developing gastric ulceration, such as patients with a history of ulcer. Misoprostol Tablet has not been shown to reduce the risk of duodenal ulcers in patients taking NSAIDs. Misoprostol Tablets should be taken for the duration of NSAID therapy.
Common Doses
- 200 mcg
- 100 mcg
Dosage
DOSAGE AND ADMINISTRATION The recommended adult oral dose of Misoprostol Tablets for reducing the risk of NSAID-induced gastric ulcers is 200 mcg four times daily with food. If this dose cannot be tolerated, a dose of 100 mcg can be used. (See Clinical Pharmacology : Clinical studies .) Misoprostol Tablets should be taken for the duration of NSAID therapy as prescribed by the physician. Misoprostol Tablets should be taken with a meal, and the last dose of the day should be at bedtime.
Black Box Warning
WARNING MISOPROSTOL ADMINISTRATION TO WOMEN WHO ARE PREGNANT CAN CAUSE BIRTH DEFECTS, ABORTION, PREMATURE BIRTH OR UTERINE RUPTURE. UTERINE RUPTURE HAS BEEN REPORTED WHEN MISOPROSTOL TABLETS WERE ADMINISTERED IN PREGNANT WOMEN TO INDUCE LABOR OR TO INDUCE ABORTION. THE RISK OF UTERINE RUPTURE INCREASES WITH ADVANCING GESTATIONAL AGES AND WITH PRIOR UTERINE SURGERY, INCLUDING CESAREAN DELIVERY (see also PRECAUTIONS and LABOR AND DELIVERY ).
Contraindications
- CONTRAINDICATIONS See boxed WARNINGS . Misoprostol Tablets should not be taken by pregnant women to reduce the risk of ulcers induced by nonsteroidal anti-inflammatory drugs (NSAIDs). Misoprostol Tablets should not be taken by anyone with a history of allergy to prostaglandins.
Side Effects
- ADVERSE REACTIONS The following have been reported as adverse events in subjects receiving Misoprostol Tablets: Gastrointestinal: In subjects receiving Misoprostol Tablets 400 or 800 mcg daily in clinical trials, the most frequent gastrointestinal adverse events were diarrhea and abdominal pain. The incidence of diarrhea at 800 mcg in controlled trials in patients on NSAIDs ranged from 14 to 40% and in all studies (over 5,000 patients) averaged 13%. Abdominal pain occurred in 13 to 20% of patients in NSAID trials and about 7% in all studies, but there was no consistent difference from placebo.
Interactions
- Drug Interactions See Clinical Pharmacology . Misoprostol Tablets has not been shown to interfere with the beneficial effects of aspirin on signs and symptoms of rheumatoid arthritis. Misoprostol Tablets does not exert clinically significant effects on the absorption, blood levels, and antiplatelet effects of therapeutic doses of aspirin. Misoprostol Tablets has no clinically significant effect on the kinetics of diclofenac or ibuprofen.