Misoprostol

INDICATIONS AND USAGE Misoprostol is indicated for reducing the risk of NSAID (nonsteroidal anti-inflammatory drugs, including aspirin)–induced gastric ulcers in patients at high risk of complications from gastric ulcer, e.g., the elderly and patients with concomitant debilitating disease, as well as patients at high risk of developing gastric ulceration, such as patients with a history of ulcer. Misoprostol Tablet has not been shown to reduce the risk of duodenal ulcers in patients taking NSAIDs. Misoprostol Tablets should be taken for the duration of NSAID therapy. Misoprostol Tablets has been shown to reduce the risk of gastric ulcers in controlled studies of 3 months' duration. It had no effect, compared to placebo, on gastrointestinal pain or discomfort associated with NSAID use.

DOSAGE AND ADMINISTRATION The recommended adult oral dose of Misoprostol Tablets for reducing the risk of NSAID-induced gastric ulcers is 200 mcg four times daily with food. If this dose cannot be tolerated, a dose of 100 mcg can be used. (See Clinical Pharmacology : Clinical studies .) Misoprostol Tablets should be taken for the duration of NSAID therapy as prescribed by the physician. Misoprostol Tablets should be taken with a meal, and the last dose of the day should be at bedtime.

ADVERSE REACTIONS The following have been reported as adverse events in subjects receiving Misoprostol Tablets: Gastrointestinal: In subjects receiving Misoprostol Tablets 400 or 800 mcg daily in clinical trials, the most frequent gastrointestinal adverse events were diarrhea and abdominal pain. The incidence of diarrhea at 800 mcg in controlled trials in patients on NSAIDs ranged from 14 to 40% and in all studies (over 5,000 patients) averaged 13%. Abdominal pain occurred in 13 to 20% of patients in NSAID trials and about 7% in all studies, but there was no consistent difference from placebo. Diarrhea was dose related and usually developed early in the course of therapy (after 13 days), usually was self-limiting (often resolving after 8 days), but sometimes required discontinuation of Misoprostol Tablets (2% of the patients). Rare instances of profound diarrhea leading to severe dehydration have been reported. Patients with an underlying condition such as inflammatory bowel disease, or those in whom dehydration, were it to occur, would be dangerous, should be monitored carefully if Misoprostol Tablets is prescribed. The incidence of diarrhea can be minimized by administering after meals and at bedtime, and by avoiding coadministration of Misoprostol Tablets with magnesium-containing antacids. Gynecological: Women who received Misoprostol Tablets during clinical trials reported the following gynecological disorders: spotting (0.7%), cramps (0.6%), hypermenorrhea (0.5%), menstrual disorder (0.3%) and dysmenorrhea (0.1%). Postmenopausal vaginal bleeding may be related to Misoprostol Tablets administration. If it occurs, diagnostic workup should be undertaken to rule out gynecological pathology. (See boxed WARNINGS .) Elderly: There were no significant differences in the safety profile of Misoprostol Tablets in approximately 500 ulcer patients who were 65 years of age or older compared with younger patients. Additional adverse events which were reported are categorized as follows: Incidence greater than 1%: In clinical trials, the following adverse reactions were reported by more than 1% of the subjects receiving Misoprostol Tablets and may be causally related to the drug: nausea (3.2%), flatulence (2.9%), headache (2.4%), dyspepsia (2.0%), vomiting (1.3%), and constipation (1.1%). However, there were no significant differences between the incidences of these events for Misoprostol Tablets and placebo. Causal relationship unknown: The following adverse events were infrequently reported. Causal relationships between Misoprostol Tablets and these events have not been established but cannot be excluded: Body as a whole: aches/pains, asthenia, fatigue, fever, chills, rigors, weight changes. Skin: rash, dermatitis, alopecia, pallor, breast pain. Special senses: abnormal taste, abnormal vision, conjunctivitis, deafness, tinnitus, earache. Respiratory: upper respiratory tract infection, bronchitis, bronchospasm, dyspnea, pneumonia, epistaxis. Cardiovascular: chest pain, edema, diaphoresis, hypotension, hypertension, arrhythmia, phlebitis, increased cardiac enzymes, syncope, myocardial infarction (some fatal), thromboembolic events (e.g., pulmonary embolism, arterial thrombosis, and CVA). Gastrointestinal: GI bleeding, GI inflammation/infection, rectal disorder, abnormal hepatobiliary function, gingivitis, reflux, dysphagia, amylase increase. Hypersensitivity: anaphylactic reaction Metabolic: glycosuria, gout, increased nitrogen, increased alkaline phosphatase. Genitourinary: polyuria, dysuria, hematuria, urinary tract infection. Nervous system/Psychiatric: anxiety, change in appetite, depression, drowsiness, dizziness, thirst, impotence, loss of libido, sweating increase, neuropathy, neurosis, confusion. Musculoskeletal: arthralgia, myalgia, muscle cramps, stiffness, back pain. Blood/Coagulation: anemia, abnormal differential, thrombocytopenia, purpura, ESR increased. To report SUSPECTED ADVERSE REACTIONS, contact Lupin Pharmaceuticlas, Inc. at 1-866-403-7592 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch

Pharmacokinetics Misoprostol 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, misoprostol is rapidly absorbed after oral administration with a Tmax of misoprostol acid of 12 ± 3 minutes and a terminal half-life of 20 to 40 minutes. There is high variability of plasma levels of misoprostol 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 misoprostol acid was noted in multiple dose studies; plasma steady state was achieved within two days. Maximum plasma concentrations of misoprostol acid are diminished when the dose is taken with food and total availability of misoprostol 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. Mean ± SD Cmax(pg/ml) AUC(0–4) (pg∙hr/ml) Tmax(min) Fasting 811 ± 317 417 ± 135 14 ± 8 With Antacid 689 ± 315 349 ± 108* 20 ± 14 With High Fat Breakfast 303 ± 176* 373 ± 111 64 ± 79* After oral administration of radiolabeled misoprostol, about 80% of detected radioactivity appears in urine. Pharmacokinetic studies in patients with varying degrees of renal impairment showed an approximate doubling of T 1/2 , C max , and AUC compared to normals, but no clear correlation between the degree of impairment and AUC. In subjects over 64 years of age, the AUC for misoprostol acid is increased. No routine dosage adjustment is recommended in older patients or patients with renal impairment, but dosage may need to be reduced if the usual dose is not tolerated. Drug interaction studies between misoprostol and several nonsteroidal anti-inflammatory drugs showed no effect on the kinetics of ibuprofen or diclofenac, and a 20% decrease in aspirin AUC, not thought to be clinically significant. Pharmacokinetic studies also showed a lack of drug interaction with antipyrine and propranolol when these drugs were given with misoprostol. Misoprostol given for 1 week had no effect on the steady state pharmacokinetics of diazepam when the two drugs were administered 2 hours apart. The serum protein binding of misoprostol acid is less than 90% and is concentration-independent in the therapeutic range. After a single oral dose of misoprostol to nursing mothers, misoprostol acid was excreted in breast milk. The maximum concentration of misoprostol acid in expressed breast milk was achieved within 1 hour after dosing and was 7.6 pg/mL (CV 37%) and 20.9 pg/ml (CV 62%) after single 200 µg and 600 µg misoprostol administration, respectively. The misoprostol acid concentrations in breast milk declined to < 1 pg/ml at 5 hours post-dose.