Misoprostol

DescriptionMisoprostol is a synthetic prostaglandin E1 analog that is commonly used for medical abortion, management of miscarriage, cervical priming, management of postpartum hemorrhage, and induction of labor. Because of misoprostol’s wide use in reproductive health, the drug is in the World Health Organization (WHO) Model List of Essential Medicines. As a synthetic analog of prostaglandin E1, misoprostol can avoid the major side effects caused by PGE1, including fetal bradycardia, pregnant women’s emesis, somnolence, and headache.

UsesInducing Labor Misoprostol is an effective and safe way of inducing labor although the Food and Drug Administration (FDA) has not yet approved it for use in pregnancy. However, the European Union (EU) approved its use after a study that was done between 2002 and 2012. It acts by causing uterine ripening and constrictions of the cervix. Abortion Misoprostol is normally used in combination with other drugs, such as methotrexate or mifepristone for medical abortion. It works by softening the cervix, causing it to open. Also, it makes the uterine muscles contract, thus inducing labor to expel the fetus. Misoprostol is a similar to prostaglandin which as a hormone that can cause a stronger reaction from the uterus. Most of the time, the drug is given in a clinic or hospital birthing centers. Misoprostol can be best administered when one has passed 12 or more weeks of pregnancy to avoid possible severe complications. It can also be administered if there is a possibility of ectopic pregnancy or if one has an intrauterine device (IUD). Misoprostol can be used either vaginally or orally if the pregnancy is still in the first trimester. The pregnant woman is advised to use 12 tablets of 200 grams and should put four tablets into the vagina or under the tongue and let it dissolve for 30 minutes. The woman is further advised to wait for 3 hours and repeat with four more pills in the vagina or under the tongue for 30 minutes. The drug is more effective when inserted into the vagina; however, doctors usually administer it orally due to the possibility of infection when used vaginally. When used together with mifepristone, misoprostol is effective in approximately 95% of early pregnancies. Postpartum Hemorrhage Misoprostol is normally used both as treatment and prevention of postpartum hemorrhage secondary to its uterotonic properties. Studies have revealed that orally administered misoprostol is less effective as compared to oxytocin, but it still plays a vital role in treating postpartum hemorrhage when other agents fail or are not available. Prevention of Ulcer Misoprostol is commonly used for the treatment and prevention of NSAID-induced gastric and duodenal ulcers due to its analgesic and anti-inflammatory properties. It acts by inhibiting gastric acid inhibition of adenylate cyclase by G-protein coupled receptor that leads to decreased proton pump activity and decreased intracellular cyclic AMP levels at the apical surface of the parietal cell. Failed Miscarriage Misoprostol is used in treating a mother in case of fetal death that can result in miscarriage. It is also used in the termination of pregnancy for fetal anomalies. Initially, a low dose is administered and doubled for the extra doses until delivery.

DescriptionMisoprostol is an orally-active PGEl analog useful in the treatment of gastric and duodenal ulcers. As with other agents of this type, misoprostol may prove useful as a gastric cytoprotective when administered concurrently with irritating drugs such as nonsteroidal antiinflammatories.

HistoryMisoprostol was discovered by Searle in 1973, it has undergone extensive clinical evaluation for peptic ulcer dis-ease and related conditions. It is a synthetic prostaglandin E1 analog approved by the US Food and Drug Administration (FDA) for preventing and treating gastric ulcers induced by nonsteroidal anti-inflammatory drugs (NSAIDs). Misoprostol has 4 primary effects, which include cytoprotection of the gastrointestinal mucosa, uterotonic properties, and the adverse effects of diarrhea, abdominal pain, and nausea. Although not FDA-approved, misoprostol is indicated for the short-term treatment of active duodenal or gastric ulcers caused by factors other than NSAIDs.

UsesMisoprostol is a cytoprotective prostaglandin PGE1 analogue that inhibits gastric acid secretion. It has many medical uses, including nine obstetric indications. The drug was originally produced by Pfizer for the treatment of gastric ulcers. Misoprostol is commonly used to prevent NSAID-induced gastric ulcers in patients at high risk of complications from a gastric ulcer, such as elderly patients and patients with a history of ulcer. It has also been used in treating duodenal ulcers unresponsive to histamine H2-antagonists; the drug does not prevent duodenal ulcers,however, in patients taking NSAIDS. Misoprostol can cause miscarriage, often associated with potentially dangerous bleeding.

General DescriptionMisoprostol, (16-(R,S)-methyl-16-hydroxy)-PGE1, methyl ester (Cytotec), is a modified prostaglandinanalog that shows potent gastric antisecretory and gastroprotectiveeffects when administered orally. Misoprostol isadministered orally in tablet form in a dose of 100 to 200 μg4 times a day to prevent gastric ulceration in susceptibleindividuals who are taking NSAIDs. Misoprostol is combinedwith the NSAID diclofenac (Voltaren) in an analgesic product(Arthrotec by Pharmacia), which is potentially safe for longtermantiarthritic therapy. This prostaglandin derivative absolutelyshould be avoided by pregnant women because of itspotential to induce abortion. In fact, the combined use of intramuscularmethotrexate and intravaginal misoprostol has beenclaimed to be a safe and effective, noninvasive method for thetermination of early pregnancy.

Preparationsynthesis of MisoprostolTo a 1000 ml dried flask under a nitrogen atmosphere was added 74.6 g of(E)-trimethyl-[[1-methyl-1-[3-(tributylstannyl)-2-propenyl]pentyl]oxy]silane,125 ml anhydrous THF and 24.2 g of copper (I) iodide. The mixture wasstirred at room temperature for 30 minutes and then it was cooled to -25 to -30°C. 98.8 ml of methyllithium (2.86 M) in DEM was added dropwise and theresultant solution was stirred at -15°C for 2 hours. Then the reaction mixturewas cooled to -78°C and 25 g of methyl-5-oxo-3-[(triethylsilyl)oxy]-1-cyclopentene-1-heptanoate in 100 ml of THF was added rapidly. After stirringthe mixture for 5 min at -78°C, it was quenched into a mixture of 750 ml ofaqueous ammonium chloride solution and 200 ml of ammonium hydroxide.The resulting mixture was warmed to room temperature and stirred until adeep blue aqueous layer was obtained. Ethyl acetate (250 ml) was used forextraction. Then the combined organic layers were washed with brine andsubsequently dried over magnesium sulfate. After a filtration andconcentration under reduced pressure, an oil (105 g) was obtained. This oilcontaining the protected prostaglandin was subjected to acidic deprotection(cat. PPTS, acetone and water) and purification (chromatography on silica gel)to provide 15.8 g (60%) of misoprostol was identical.