Misolast 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, Misolast is rap >max of Misolast acid of 12 ± 3 minutes and a terminal half-life of 20 to 40 minutes.
There is high variability of plasma levels of Misolast 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. No accumulation of Misolast acid was noted in multiple dose studies; plasma steady state was achieved within two days.
Maximum plasma concentrations of Misolast acid are diminished when the dose is taken with food and total availability of Misolast acid is reduced by use of concomitant antacid. Clinical trials were conducted with concomitant antacid, however, so this effect does not appear to be clinically important.
How is Misolast Supplied
Misolast Tablets 200-mcg tablets are round, white flat-faced beveled edge bisected tablets, debossed "161" above the bisect and "n" below the bisect and plain on the other side; supplied as:
Bottles of 1: 54348-148-00
Bottles of 1: 54348-148-01
Bottles of 2: 54348-148-02
Bottles of 3: 54348-148-03
Bottles of 4: 54348-148-04
Bottles of 6: 54348-148-06
Bottles of 8: 54348-148-08
Store at 20° to 25°C (68° to 77°F) . Store in a dry area.
Misolast is a synthetic prostaglandin E1 analogue that is used off-label for a variety of indications in the practice of obstetrics and gynecology, including medication abortion, medical management of miscarriage, induction of labor, cervical ripening before surgical procedures, and the treatment of postpartum hemorrhage. Due to its wide-ranging applications in reproductive health, Misolast is on the World Health Organization Model List of Essential Medicines. This article briefly reviews the varied uses of Misolast in obstetrics and gynecology.
Misolast is a synthetic prostaglandin E1 analogue marketed as an oral preparation used to prevent and treat gastroduodenal damage induced by nonsteroidal anti-inflammatory drugs (NSAIDs). However, Misolast is used off-label for a variety of indications in the practice of obstetrics and gynecology, including medication abortion, medical management of miscarriage, induction of labor, cervical ripening before surgical procedures, and the treatment of postpartum hemorrhage. Misolast’s effects are dose dependent and include cervical softening and dilation, uterine contractions, nausea, vomiting, diarrhea, fever, and chills. 1 Although Misolast is not approved by the US Food and Drug Administration (FDA) for these indications, in 2002, pregnancy was removed from the label as an absolute contraindication to Misolast use. 2 Misolast’s advantages over other synthetic prostaglandin analogues are its low cost, long shelf life, lack of need for refrigeration, and worldwide availability ( Figure 1 ). 3
ВїPara cuГЎles condiciones o enfermedades se prescribe este medicamento?
El Misolast se usa para prevenir las Гєlceras en las personas que toman ciertos medicamentos para la artritis o el dolor, incluyendo las aspirinas, que pueden provocar Гєlceras. Protege la mucosa que recubre el estГіmago y reduce la producciГіn de secreciГіn ГЎcida.
A synthetic PGE1 analogue administered vaginally with mifepristone (RU 486) as an abortifacient. It is also used to prevent NSAID-induced gastric ulcers and in patients with a history of GI bleeding. Misolast may be of use in reducing acute rejection of renal allografts, a phenomenon partially due to ischaemic damage of kidneys that occurs between the time of “harvesting” and re-establishment of the blood flow; Misolast-treated group subjects suffered acute rejection one-half as often as the placebo group.
When compared to PGE2, Misolast induces complete abortion (i.e., passage of foetus and placenta simultaneously) more often (43% vs 32% for PGE2), was more convenient (insertion of two 100-µg tablets at 12 hours vs insertion of 20 mg suppository every 3 hours, plus antidiarrhoeal, antiemetic and antipyretic medication required for PGE2 therapy), was associated with fewer side effects, including fever (11% vs 63%), vomiting (4% vs 33%) and diarrhoea (4% vs 30%), and is less expensive (USD $0.97 vs $315.30).
Routes of Misolast administration include oral, vaginal, sublingual, buccal, or rectal. Pharmacokinetics studies ( Figure 2 ) comparing oral and vaginal administration have shown that vaginal Misolast is associated with slower absorption, lower peak plasma levels, and slower clearance, similar to an extended-release preparation. 4 – 6 Vaginal Misolast is also associated with a greater overall exposure to the drug (area under the curve ) and greater effects on the cervix and uterus. 5 There is, however, a wide variation in the absorption of Misolast through the vaginal epithelium among different women. 3 There is no clinically significant difference between vaginal Misolast that is administered dry and vaginal Misolast moistened with water, saline, or acetic acid. 7 – 9
WHERE TO BUY MISOPROSTOL
In most countries, Misolast can be purchased in pharmacies as Cytotec or under some other trade name as an anti-ulcer medication. Some pharmacies may ask for a medical prescription for this purpose. Buying so-called “abortion drugs” on the black market or from unknown Internet sources is not recommended. Women can also purchase the combined mifepristone-Misolast regimen online from Women on Web in the Netherlands (http://www.womenonweb.org) with a donation of 70-90 Euros (exceptions are made in difficult cases). This price may be higher than Misolast tablets purchased locally, but the drugs are of known quality, and the combined regimen is significantly more effective than Misolast used alone. Women Help Women (https://womenhelp.org) and Safe2Choose (https://safe2choose.org) also provide safe access to abortion medication.
For more information on medical abortion, consult these web sites:
Other pharmacologic effects
Misolast Tablets does not produce clinically significant effects on serum levels of prolactin, gonadotropins, thyroid-stimulating hormone, growth hormone, thyroxine, cortisol, gastrointestinal hormones (somatostatin, gastrin, vasoactive intestinal polypeptide, and motilin), creatinine, or uric acid. Gastric emptying, immunologic competence, platelet aggregation, pulmonary function, or the cardiovascular system are not modified by recommended doses of Misolast Tablets.
In these trials there were no significant differences between Misolast Tablets and placebo in relief of day or night abdominal pain. No effect of Misolast Tablets in reducing the risk of duodenal ulcers was demonstrated, but relatively few duodenal lesions were seen.
In another clinical trial, 239 patients receiving aspirin 650 to 1300 mg q.i.d. for rheumatoid arthritis who had endoscopic evidence of duodenal and/or gastric inflammation were randomized to Misolast 200 mcg q.i.d. or placebo for 8 weeks while continuing to receive aspirin. The study evaluated the possible interference of Misolast Tablets on the efficacy of aspirin in these patients with rheumatoid arthritis by analyzing joint tenderness, joint swelling, physician's clinical assessment, patient's assessment, change in ARA classification, change in handgrip strength, change in duration of morning stiffness, patient's assessment of pain at rest, movement, interference with daily activity, and ESR. Misolast Tablets did not interfere with the efficacy of aspirin in these patients with rheumatoid arthritis.
What is Misolast (Cytotec)?
Misolast reduces stomach acid and helps protect the stomach from damage that can be caused by taking a nonsteroidal anti-inflammatory drug (NSAID) such as aspirin, ibuprofen (Advil, Motrin), naproxen (Aleve), celecoxib, diclofenac, indomethacin, meloxicam, and others.
Misolast is used to prevent stomach ulcers during treatment with aspirin or an NSAID.
Misolast may also be used for purposes not listed in this medication guide.