Misoprostol administration to women who are pregnant can cause birth defects, abortion, premature birth, or uterine rupture. Uterine rupture has been reported when misoprostol was 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. Misoprostol should not be taken by pregnant women to reduce the risk of ulcers induced by NSAIDs.
Patients must be advised of the abortifacient property and warned not to give the drug to others.
Misoprostol should not be used for reducing the risk of NSAID-induced ulcers in women of childbearing potential unless the patient is at high risk of complications from gastric ulcers associated with use of the NSAID, or is at high risk of developing gastric ulceration. In such patients, misoprostol may be prescribed if the patient has had a negative serum pregnancy test within 2 weeks prior to beginning therapy; is capable of complying with effective contraceptive measures; has received both oral and written warnings of the hazards of misoprostol, the risk of possible contraception failure, and the danger to other women of childbearing potential if the drug is taken by mistake; and will begin misoprostol only on the second or third day of the next normal menstrual period.
Cervical ripening for labor induction (off-label use): Note: Avoid use in patients with prior cesarean birth or other major uterine surgery due to increased risk of uterine rupture (Ref). Use caution in patients with preexisting regular painful uterine contractions due to risk of excessive uterine activity (Ref). Monitor fetal heart rate and uterine activity continuously for at least 30 minutes following administration and for as long as regular uterine activity persists (Ref). The ideal dosing regimen has not been established (Ref); examples of regimens are listed below. Refer to institution-specific protocols.
Intravaginal: 25 mcg (one-fourth of 100 mcg tablet); may repeat at intervals of 3 to 6 hours. Higher doses (ie, 50 mcg every 6 hours) may be used in some cases but are associated with an increased risk of adverse events (eg, uterine tachysystole with fetal heart rate decelerations) (Ref).
Oral: 25 mcg (one-fourth of 100 mcg tablet); may repeat at intervals of 2 hours (Ref).
Discontinuation of therapy: Typically continued until the cervix is favorable. If cervix remains unfavorable, may switch to alternative method (eg, balloon catheter), oxytocin, or postpone induction (if no medical contraindications) (Ref). Do not initiate oxytocin sooner than 4 hours after the last misoprostol dose (Ref).
NSAID-induced gastric ulcers, prevention: Note: May be used for prevention of nonsteroidal anti-inflammatory drug (NSAID)–induced gastric ulcers in selected high-risk patients but is not a preferred agent for this indication (Ref).
Oral: 200 mcg 4 times daily; if not tolerated, may decrease dose to 100 mcg 4 times daily.
Postpartum uterine hemorrhage (off-label use): Note: The ideal dosing regimen has not been established and various protocols are available; examples of regimens are listed below. Refer to institution-specific protocols.
Prevention of postpartum hemorrhage: Note: Administer after delivery of the placenta, delivery of the anterior shoulder, or after delayed umbilical cord clamping (Ref). May be used in combination with oxytocin (eg, for patients at high risk of hemorrhage) or as monotherapy when oxytocin is not available or cannot be used. Some experts use combination therapy in all patients regardless of hemorrhage risk (Ref).
Combination therapy (with oxytocin):
Buccal, Sublingual: 200 to 400 mcg as a single dose (Ref).
Monotherapy:
Oral: 400 to 600 mcg as a single dose (Ref).
Sublingual: 600 mcg as a single dose (Ref).
Rectal (alternative route): 400 to 800 mcg as a single dose (Ref). Note: Rectal administration has a slower onset and lower bioavailability compared with other routes (Ref).
Treatment of postpartum hemorrhage: Note: Prompt administration of uterotonic medication(s) for postpartum hemorrhage (an obstetric emergency) is required; if hemorrhage is not controlled by medications, minimally invasive measures and/or emergency invasive intervention may also be warranted (Ref). Misoprostol may be used for the treatment of postpartum hemorrhage unresponsive to oxytocin (with or without tranexamic acid), or as monotherapy when oxytocin is not available or cannot be used (Ref). Some experts prefer other injectable uterotonics (eg, carboprost, methylergonovine) prior to misoprostol use (Ref).
Sublingual: 800 mcg as a single dose (Ref) (range: 400 to 1,000 mcg) (Ref). Lower doses (eg, 400 mcg) may be sufficient when used as adjunctive therapy (Ref).
Oral, Rectal (alternative routes): 600 to 1,000 mcg as a single dose (Ref). Note: These routes are generally not preferred due to a slower onset and lower bioavailability compared with sublingual route (Ref).
Pregnancy loss (miscarriage), first or second trimester (off-label use): Note: Combination therapy with mifepristone and misoprostol is generally preferred to misoprostol monotherapy due to better efficacy (Ref). Refer to Mifepristone monograph for mifepristone dosing.
Combination therapy with mifepristone (preferred):
First trimester:
Misoprostol administration: Buccal, Sublingual, Intravaginal: Misoprostol 800 mcg taken 24 to 48 hours after mifepristone (Ref). Shorter dosing intervals between mifepristone and misoprostol (eg, 7 to 20 hours) have also been described (Ref).
Repeat misoprostol doses: Buccal, Sublingual, Intravaginal: For patients at ≥10 weeks' gestation, repeat 800 mcg every 3 hours until fetal expulsion (Ref). For patients at <10 weeks' gestation with no to minimal bleeding after the initial dose, repeat dose at approximately 24 hours (range 3 hours to 7 days) (Ref).
Second trimester:
Misoprostol administration: Buccal, Sublingual, Intravaginal: Misoprostol 400 mcg taken 24 to 48 hours after mifepristone (Ref).
Repeat misoprostol doses: Buccal, Sublingual, Intravaginal: Repeat 400 mcg every 3 to 6 hours until expulsion (Ref).
Monotherapy:
First trimester:
Buccal, Sublingual, Intravaginal: 800 mcg as a single dose (Ref). May repeat dose at ≥3-hour intervals (eg, every 3 to 24 hours) if needed until expulsion (Ref).
Second trimester:
Buccal, Sublingual, Intravaginal: 400 mcg every 3 to 6 hours until expulsion (Ref).
Pregnancy termination, medication abortion: Note: Combination therapy with mifepristone and misoprostol is generally preferred to misoprostol monotherapy due to better efficacy (Ref). The ideal dosing regimen has not been established and various protocols are available; examples of regimens are listed below. Refer to Mifepristone monograph for mifepristone dosing.
Combination therapy with mifepristone (preferred) (off-label use after 70 days' gestation):
First trimester:
Misoprostol administration: Buccal, Sublingual, Intravaginal: Misoprostol 800 mcg taken 24 to 48 hours after mifepristone (Ref).
Repeat misoprostol doses: Buccal, Sublingual, Intravaginal: For patients at ≥9 to <12 weeks' gestation, give an automatic 800 mcg dose for the patient to self-administer 3 to 6 hours after the first dose. For patients at <9 weeks' gestation with no to minimal bleeding, may repeat 800 mcg once at approximately 24 hours (range 4 to 24 hours) (Ref).
Second trimester (off-label use):
Misoprostol administration: Buccal, Sublingual, Intravaginal: Misoprostol 400 mcg taken 24 to 48 hours after mifepristone (Ref). Shorter dosing intervals between mifepristone and misoprostol (eg, simultaneous dosing, 12 hours between doses) have also been found to be safe and effective (Ref).
Repeat misoprostol doses: Buccal, Sublingual, Intravaginal: Repeat every 3 hours until expulsion (Ref).
Monotherapy (off-label use):
First trimester:
Buccal, Sublingual, Intravaginal: 800 mcg every 3 hours until expulsion (Ref).
Second trimester:
Buccal, Sublingual, Intravaginal: 400 mcg every 3 hours until expulsion (Ref).
Retained products of conception (first half of pregnancy), treatment (off-label use): Note: Referred to as incomplete abortion when occurs after pregnancy loss (ie, miscarriage) or termination. Hemodynamically unstable patients or those with other complications (eg, infection, hemorrhage) may require surgical intervention with or without additional treatment (eg, antibiotics, uterine artery embolization). Hemodynamically stable patients may be managed expectantly or with medical management if symptomatic (eg, prolonged bleeding) (Ref).
First trimester:
Buccal: 800 mcg as a single dose (Ref).
Oral: 600 mcg as a single dose (Ref).
Sublingual: 400 mcg as a single dose (Ref).
Second trimester:
Buccal, Sublingual: 400 mcg every 3 hours (Ref).
Dosage adjustment for concomitant therapy: Significant drug interactions exist, requiring dose/frequency adjustment or avoidance. Consult drug interactions database for more information.
Dose adjustment is not routinely needed; however, the dose may be reduced if the recommended dose is not tolerated. It is not known if misoprostol is removed by dialysis.
There are no dosage adjustments provided in the manufacturer's labeling.
Nonsteroidal anti-inflammatory drug–induced gastric ulcers, prevention: Refer to adult dosing.
The following adverse drug reactions and incidences are derived from product labeling unless otherwise specified. Adverse reactions reported in adults.
>10%: Gastrointestinal: Abdominal pain, diarrhea (including severe diarrhea)
1% to 10%:
Gastrointestinal: Constipation, dyspepsia, flatulence, nausea, vomiting
Nervous system: Headache
<1%:
Cardiovascular: Acute myocardial infarction, arterial thrombosis, cardiac arrhythmia, chest pain, edema, hypertension, hypotension, increased cardiac enzymes in blood specimen, phlebitis, pulmonary embolism, syncope
Dermatologic: Alopecia, dermatitis, diaphoresis, pallor, skin rash
Endocrine & metabolic: Increased thirst, loss of libido, weight changes
Gastrointestinal: Change in appetite, dysgeusia, dysphagia, gastroesophageal reflux disease, gastrointestinal hemorrhage, gastrointestinal infection, gastrointestinal inflammation, gingivitis, increased amylase, rectal disease
Genitourinary: Dysuria, glycosuria, gynecological disease (dysmenorrhea, heavy menstrual bleeding, menstrual disease, spotty menstruation, uterine cramps), hematuria, impotence, mastalgia, urinary tract infection
Hematologic & oncologic: Abnormal white blood cell differential, anemia, increased erythrocyte sedimentation rate, purpuric disease, thrombocytopenia
Hepatic: Abnormal hepatobiliary function, increased serum alkaline phosphatase
Hypersensitivity: Anaphylaxis
Nervous system: Anxiety, asthenia, body pain, cerebrovascular accident, chills, confusion, depression, dizziness, drowsiness, fatigue, neuropathy, neurosis, pain, rigors
Neuromuscular & skeletal: Arthralgia, back pain, gout, muscle cramps, myalgia, stiffness
Ophthalmic: Conjunctivitis, visual disturbance
Otic: Deafness, otalgia, tinnitus
Renal: Increased blood urea nitrogen, polyuria
Respiratory: Bronchitis, bronchospasm, dyspnea, epistaxis, pneumonia, upper respiratory tract infection
Miscellaneous: Fever
Frequency not defined: Genitourinary: Abortion, premature labor
Postmarketing:
Genitourinary: Uterine rupture
Hematologic & oncologic: Abnormal platelet aggregation (Beales 1997), prolonged bleeding time (Beales 1997)
Hypersensitivity to misoprostol, other prostaglandins, or any component of the formulation; pregnancy
When used for termination of intrauterine pregnancy (additional contraindications): Refer to Mifepristone monograph.
Concerns related to adverse effects:
• Abortifacient: Patients must be advised of the abortifacient property and warned not to give misoprostol to others.
Disease-related concerns:
• Cardiovascular disease: Use with caution in patients with cardiovascular disease.
Other warnings/precautions:
• Appropriate use: Pregnancy termination: Misoprostol is approved for use with mifepristone for pregnancy termination. Refer to mifepristone warnings, precautions, and contraindications for appropriate use of misoprostol for this indication.
• Appropriate use: Gastric ulcers: For use only in patients at high risk of complications from gastric ulcers (eg, elderly patients, patients with concomitant diseases) or patients at high risk for developing gastric ulcers (eg, those with a history of ulcers) taking nonsteroidal anti-inflammatory drug (NSAIDs) (including aspirin). Misoprostol must be taken during the duration of NSAID therapy. It is not effective in preventing duodenal ulcers in patients taking NSAIDs.
Excipient information presented when available (limited, particularly for generics); consult specific product labeling.
Tablet, Oral:
Cytotec: 100 mcg
Cytotec: 200 mcg [scored]
Generic: 100 mcg, 200 mcg
Yes
Tablets (Cytotec Oral)
100 mcg (per each): $4.84
200 mcg (per each): $7.05
Tablets (miSOPROStol Oral)
100 mcg (per each): $0.50 - $0.98
200 mcg (per each): $0.60 - $1.50
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Excipient information presented when available (limited, particularly for generics); consult specific product labeling.
Tablet, Oral:
Generic: 100 mcg, 200 mcg
Oral:
Nonsteroidal anti-inflammatory drug (NSAID)–induced gastric ulcers, prevention: Administer with food and avoid magnesium-containing antacids (minimizes diarrhea); take last dose of the day at bedtime. Continue therapy through the duration of NSAID therapy. Initiate on the second or third day of a normal menstrual period in patients of reproductive potential.
Pregnancy termination, combination therapy: Refer to the Mifepristone monograph.
Cervical ripening for labor induction (off-label use): Because the recommended doses require breaking of the commercially available tablets, some reports recommend weighing the tablet fragments (for oral or vaginal use) to ensure accurate dosing (Ref).
Misoprostol is available as an oral tablet. Administration of the tablet via the buccal, sublingual, vaginal, and rectal routes has been evaluated. Each route provides different pharmacokinetic and adverse event profiles which may benefit specific indications (Ref).
Hazardous agent (NIOSH 2024 [table 2]).
Use appropriate precautions for receiving, handling, storage, preparation, dispensing, transporting, administration, and disposal. Follow NIOSH and USP 800 recommendations and institution-specific policies/procedures for appropriate containment strategy (NIOSH 2023; NIOSH 2024; USP-NF 2020).
Note: Facilities may perform risk assessment of some hazardous drugs to determine if appropriate for alternative handling and containment strategies (USP-NF 2020). Refer to institution-specific handling policies/procedures.
NSAID-induced gastric ulcers, prevention: To reduce the risk of nonsteroidal anti-inflammatory drug (NSAID)–induced gastric ulcers in patients at high risk of complications.
Pregnancy termination, medication abortion: Pregnancy termination (medication abortion) through 70 days' gestation in combination with mifepristone (Mifeprex prescribing information).
Cervical ripening for labor induction; Postpartum hemorrhage, prevention or treatment; Pregnancy loss (miscarriage), first or second trimester, monotherapy; Pregnancy termination, medication abortion, monotherapy; Retained products of conception (first half of pregnancy), treatment
Cytotec may be confused with Cytoxan
MiSOPROStol may be confused with metoprolol, miFEPRIStone
The Institute for Safe Medication Practices (ISMP) includes this medication among its list of drugs (contraindicated in pregnancy) which have a heightened risk of causing significant patient harm when used in error (High-Alert Medications in Community/Ambulatory Care Settings).
None known.
Note: Interacting drugs may not be individually listed below if they are part of a group interaction (eg, individual drugs within “CYP3A4 Inducers [Strong]” are NOT listed). For a complete list of drug interactions by individual drug name and detailed management recommendations, use the drug interactions program by clicking on the “Launch drug interactions program” link above.
Antacids: May increase adverse/toxic effects of MiSOPROStol. More specifically, concomitant use with magnesium-containing antacids may increase the risk of diarrhea. Management: Avoid concomitant use of misoprostol and magnesium-containing antacids. In patients requiring antacid therapy, employ magnesium-free preparations. Monitor for increased adverse effects (e.g., diarrhea, dehydration). Risk X: Avoid
Oxytocic Agents: MiSOPROStol may increase adverse/toxic effects of Oxytocic Agents. Specifically, the oxytocic effects may be increased. Management: The concomitant use of misoprostol with other oxytocic agents is not recommended. If sequential use of oxytocin is necessary, oxytocin should be given at least 4 hours after misoprostol. Risk X: Avoid
Phenylbutazone: May increase neurotoxic effects of MiSOPROStol. Specifically, the combination may result in headache, dizziness, and transient diplopia. Risk C: Monitor
Sulprostone: May increase adverse/toxic effects of MiSOPROStol. Risk X: Avoid
Misoprostol peak serum concentrations may be decreased if taken with food (not clinically significant).
Misoprostol should not be used for reducing the risk of nonsteroidal anti-inflammatory drug (NSAID)–induced ulcers in patients of childbearing potential unless the patient is at high risk of complications from gastric ulcers associated with use of the NSAIDs, or is at high risk of developing gastric ulceration. When needed, misoprostol may be prescribed if the patient has had a negative serum pregnancy test within 2 weeks prior to beginning therapy; is capable of complying with effective contraceptive measures; has received both oral and written warnings of the hazards of misoprostol, the risk of possible contraception failure, and the danger to other patients of childbearing potential if the drug is taken by mistake; and will begin misoprostol only on the second or third day of the next normal menstrual period. Advise patients of the abortifacient property and warn not to give the drug to others.
Misoprostol is used for pregnancy termination (medication abortion). In sexually active patients, pregnancy can occur prior to the first menstrual period following treatment. Appropriate contraception can be started as soon as termination of pregnancy is confirmed or before sexual intercourse is resumed. Pregnancy termination via medication abortion does not adversely affect future fertility (ACOG 2020).
Placental transfer of misoprostol acid (the active metabolite of misoprostol) was detected following a single 25 mcg vaginal misoprostol dose for labor induction (de Oliveira Filgueira 2021).
Misoprostol should not be taken by pregnant patients to reduce the risk of ulcers induced by nonsteroidal anti-inflammatory drug; the use of misoprostol for this indication is contraindicated during pregnancy.
Misoprostol administration to pregnant patients may cause birth defects, abortion, or premature birth. Congenital anomalies following first trimester exposure include skull defects, cranial nerve palsies, facial malformations, and limb defects. Misoprostol may produce uterine contractions leading to fetal death, uterine perforation, or abortion. Patients must be advised of the abortifacient property. Uterine tachysystole may occur and progress to uterine tetany; uteroplacental blood flow may be impaired and uterine rupture or amniotic fluid embolism leading to adverse fetal heart changes may occur.
Uterine rupture has been reported when misoprostol was administered in pregnant patients to induce labor or to induce abortion. The risk of uterine rupture increases with advancing gestational age, grand multiparity, and with prior uterine surgery, including cesarean delivery. Monitor uterine activity and fetal status in a hospital setting. Do not use misoprostol in situations where uterotonic drugs are otherwise contraindicated or inappropriate.
Misoprostol is FDA approved for pregnancy termination (medication abortion) through 70 days gestation in conjunction with mifepristone (refer to the Mifepristone monograph for details). It also may be used as monotherapy when mifepristone is not available (ACOG 2020; WHO 2022). Pregnancy termination via medication abortion is not recommended for patients with chronic adrenal failure, porphyrias, coagulopathy or concurrent anticoagulant therapy, intrauterine device in place, ectopic pregnancy or concurrent long-term corticosteroid therapy (ACOG 2020).
Because misoprostol may induce or augment uterine contractions, it has been used off label as a cervical-ripening agent and for induction of labor. Do not use misoprostol for this purpose during the third trimester in conditions where a spontaneous labor and vaginal delivery would be contraindicated, including patients who have had a prior cesarean delivery or major uterine surgery (because the risk of uterine rupture is increased) (ACOG 2009; ACOG 2019).
Misoprostol may be used off-label to manage the retained products of conception (eg, incomplete abortion, defined as the passage of some but not all products of conception in a patient with an open cervix) (WHO 2022). Misoprostol is also used off-label for the treatment of pregnancy loss (miscarriage) during the first or second trimesters (ACOG 2018; FIGO 2023b; WHO 2022).
Misoprostol is effective for the management of postpartum hemorrhage. Misoprostol as adjunctive therapy with oxytocin has been used off label in high-risk patients; monotherapy is recommended in situations where oxytocin is not available (eg, resource-poor settings) or cannot be used. The risk of adverse reactions may be associated with combination therapy (ACOG 2017; FIGO [Escobar 2022]; Gallos 2018; Koch 2019; Morfaw 2019; SOGC [Robinson 2022]; Sweed 2018). Various routes of administration have been used for postpartum hemorrhage (buccal, oral, rectal, sublingual). Sublingual administration has the highest bioavailability, rapid onset, and a moderate duration of action. Rectal administration has the lowest bioavailability and serum concentrations may not reach clinical significance (SOGC [Robinson 2022]). Dose-related fever, shivering, nausea, vomiting, and diarrhea are associated with use of misoprostol (FIGO [Escobar 2022]; SOGC [Robinson 2022]). Buccal administration may be associated with lower plasma concentrations and a decreased risk of adverse reactions compared to sublingual administration (Schaff 2005).
Misoprostol acid (the active metabolite of misoprostol) is present in breast milk.
Peak milk concentrations of misoprostol acid occur within 1 hour after an oral maternal dose and generally decline over 5 hours (Abdel-Aleem 2003; Vogel 2004). The authors of one study suggest taking the maternal dose immediately after a feed; the next feed would be acceptable in 3 to 4 hours (Vogel 2004).
The manufacturer recommends that caution be used if administered to patients who are breastfeeding.
When used for the prevention of NSAID-induced ulcers, take with food.
Cervical ripening for labor induction: Fetal heart rate and uterine activity continuously for at least 30 minutes following administration and for as long as regular uterine activity persists (ACOG 2009).
Postpartum hemorrhage: Heart rate, BP, blood loss, temperature (FIGO [Escobar 2022]).
Pregnancy loss (miscarriage): Evaluate Rh status; ultrasound or serial serum β-hCG (if ultrasound not available) 1 to 2 weeks after dosing; patient reported symptoms (ACOG 2018).
Pregnancy termination: Refer to Mifepristone monograph.
Prevention of nonsteroidal anti-inflammatory drug–induced gastric ulcers: Pregnancy test within 2 weeks prior to therapy in patients who may become pregnant; adequate diagnostic measures in all cases of undiagnosed abnormal vaginal bleeding.
Misoprostol is a synthetic prostaglandin E1 analog that replaces the protective prostaglandins consumed with prostaglandin-inhibiting therapies (eg, NSAIDs); has been shown to induce uterine contractions
Onset of action: Inhibition of gastric acid secretion: 30 minutes
Duration of action: Inhibition of gastric acid secretion: 3 hours
Absorption: Rapid and extensive; extensive; food decreases absorption of misoprostol acid
Protein binding: Misoprostol acid: <90%
Metabolism: Hepatic; rapid de-esterification to misoprostol acid (active)
Half-life elimination: Misoprostol acid: 20 to 40 minutes
Time to peak, serum: Misoprostol acid: Fasting: 12 ± 3 minutes
Excretion: Urine (80%)
Altered kidney function: Cmax, AUC, and t½ are almost doubled, but no clear correlation between degree of impairment and AUC is shown.
Older adult: AUC is increased in patients >64 years of age.