Misoprostol
Pronouncation: (MY-so-PRAHST-ole)Class: Prostaglandin
Trade Names:
Cytotec
- Tablets 100 mcg
- Tablets 200 mcg
Novo-Misoprostol (Canada)
Pharmacology
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Feedback for Misoprostol
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Synthetic prostaglandin E 1 analog that inhibits gastric acid secretion and exerts mucosal-protective properties.
Pharmacokinetics
Absorption
Misoprostol is extensively absorbed. T max is approximately 12 min. Food decreases C max and total availability of misoprostol acid is reduced by the use of concomitant antacid.
Distribution
Less than 90% is protein bound and displays linear kinetics.
Metabolism
Misoprostol undergoes rapid de-esterification to its free acid, which is responsible for its clinical activity. It does not affect the hepatic mixed function oxidase CYP-450 enzyme system.
Elimination
Approximately 80% is detected in urine and the t ½ is 20 to 40 min.
Special Populations
Renal Function ImpairmentC max , AUC, and t ½ are almost doubled, but no clear correlation between degree of impairment and AUC is shown. No dosage adjustment is recommended. However, dose reduction my be needed if patient does not tolerate.
ElderlyAUC is increased in patients older than 64 yr of age. However, no dose adjustment is needed.
Indications and Usage
Prevention of gastric ulcers in high-risk patients who are taking NSAIDs.
Contraindications
History of allergy to prostaglandins; pregnancy.
Dosage and Administration
AdultsPO 100 to 200 mcg 4 times daily, in conjunction with NSAID therapy.
Storage/Stability
Store tablets below 77° F. Protect from moisture.
Drug Interactions
None well documented.
Laboratory Test Interactions
None well documented.
Adverse Reactions
CNS
Headache (2%).
GI
Diarrhea (14% to 40% [dose-related]); abdominal pain (13% to 20%); nausea, flatulence (3%); dyspepsia (2%); vomiting, constipation (1%).
Precautions
WarningsAbortion, premature birth, birth defects, and uterine rupture have been reported when misoprostol is administered in pregnant women to induce labor or abortion beyond week 8 of pregnancy. Misoprostol should not be taken by pregnant women for risk reduction of NSAID ulcers. Counsel patients on abortifacient properties. Monitoring recommendationsPrescribe for NSAID ulcer reduction in women only if serum pregnancy test is negative when administered within 2 wk prior to therapy and patient is capable of contraception compliance. Written and oral patient counseling is required. Begin therapy only on second or third day of the next menstrual period. |
Pregnancy
Category X .
Lactation
Undetermined.
Children
Safety and efficacy not established in children younger than 18 yr of age.
Elderly
Reduce dosage if usual dose is not tolerated.
Renal Function
May reduce drug Cl; routine dosage adjustment is not recommended unless usual dose is not tolerated.
Fertility
May adversely affect fertility.
Diarrhea
Dose related (13% to 40%); usually develops early in course of therapy (after 13 days) and is usually self-limiting (resolving after 8 days).
Duodenal ulcers
Not for prevention of duodenal ulcers in patients on NSAIDs.
Overdosage
Symptoms
Sedation, tremor, seizure, dyspnea, abdominal pain, diarrhea, fever, palpitations, hypotension, bradycardia.
Patient Information
- Advise patient to read patient information leaflet before starting therapy and with each refill.
- Advise patient that medication is not used to treat stomach ulcers but is being used to prevent the NSAID from causing stomach ulcers and that the medication must be taken regularly, as prescribed, for this beneficial effect to occur.
- Advise patient to take prescribed dose with or after a meal to reduce risk of diarrhea.
- Advise patient to take the last dose of the day just before bedtime.
- Caution patient not to change the dose or stop taking unless advised by health care provider.
- Advise patient that diarrhea is the most common adverse reaction of misoprostol and that taking each dose with or after meals and avoiding magnesium-containing antacids may minimize this problem.
- Advise patient to notify health care provider if symptoms of stomach ulcer develop (eg, indigestion, stomach pain), or if intolerable adverse reactions (eg, diarrhea, cramping) develop.
- Caution women of childbearing potential to use an effective method of contraception while taking this medication and for 1 mo or for 1 menstrual cycle after misoprostol has been discontinued.
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More Misoprostol resources:
Misoprostol - Includes detailed dosage instructions.
Abortion, Duodenal Ulcer, Stomach Ulcer, Labor Induction, Cervical Ripening, Postpartum Bleeding, NSAID-Induced Ulcer Prophylaxis, Gynecological Conditions
