A synthetic analog of natural prostaglandin E1. It produces a dose-related inhibition of gastric acid and pepsin secretion, and enhances mucosal resistance to injury. It is an effective anti-ulcer agent and also has oxytocic properties.
Indicated for the treatment of ulceration (duodenal, gastric and NSAID induced) and prophylaxis for NSAID induced ulceration. Misoprostol is also indicated for other uses that are not approved in Canada, including the medical termination of an intrauterine pregnancy used alone or in combination with methotrexate,as well as the induction of labour in a selected population of pregnant women with unfavourable cervices.
This indication is avoided in women with prior uterine surgery or cesarean surgery due to an increased risk of possible uterine rupture. Misoprostol is also used for the prevention or treatment of serious postpartum hemorrhage.
Misoprostol is a prostaglandin E1 (PGE1) analogue used for the treatment and prevention of stomach ulcers.
When administered, misoprostol stimulates increased secretion of the protective mucus that lines the gastrointestinal tract and increases mucosal blood flow, thereby increasing mucosal integrity. It is sometimes co-prescribed with non-steroidal anti-inflammatory drugs (NSAIDs) to prevent the occurrence of gastric ulceration, a common adverse effect of the NSAIDs.
Misoprostol seems to inhibit gastric acid secretion by a direct action on the parietal cells through binding to the prostaglandin receptor. The activity of this receptor is mediated by G proteins which normally activate adenylate cyclase. The indirect inhibition of adenylate cyclase by Misoprostol may be dependent on guanosine-5’-triphosphate (GTP).
The significant cytoprotective actions of misoprostol are related to several mechanisms. These include: 1. Increased secretion of bicarbonate, 2. Considerable decrease in the volume and pepsin content of the gastric secretions, 3. It prevents harmful agents from disrupting the tight junctions between the epithelial cells which stops the subsequent back diffusion of H+ ions into the gastric mucosa, 4. Increased thickness of mucus layer, 5. Enhanced mucosal blood flow as a result of direct vasodilatation, 6. Stabilization of tissue lysozymes/vascular endothelium, 7. Improvement of mucosal regeneration capacity, and 8. Replacement of prostaglandins that have been depleted as a result of various insults to the area.
Misoprostol has also been shown to increase the amplitude and frequency of uterine contractions during pregnancy via selective binding to the EP-2/EP-3 prostanoid receptors.
Metabolism: Rapidly de-esterified to misoprostol acid. The de-esterified metabolite undergoes further metabolism by beta and omega oxidation; oxidation is followed by reduction of the ketone to yield prostaglandin F analogs.
Absorption: Misoprostol is extensively absorbed.
Route of elimination: After a single oral dose of misoprostol to nursing mothers, misoprostol acid was excreted in breast milk.
Half life: 20-40 minutes
All medicines may cause side effects, but many people have no, or minor, side effects.Some medical conditions may interact with Misoprostol.
Tell your doctor or pharmacist if you have any medical conditions.
Common side effects may include: diarrhea, stomach pain, nausea, upset stomach, gas, vaginal bleeding or spotting, heavy menstrual flow or menstrual cramps.
Misoprostol can cause birth defects, premature birth, uterine rupture, miscarriage, or incomplete miscarriage and dangerous uterine bleeding. Do not use misoprostol if you are pregnant. If you are able to become pregnant, you will need to have a negative pregnancy test before starting this treatment. You will also need to use effective birth control to prevent pregnancy during treatment.
This is not a complete list of all side effects that may occur. If you have questions about side effects, contact your health care provider.
