^ Serious Skin Reactions
NSAIDs, including diclofenac, a component of diclofenac sodium/misoprostol, can cause serious skin adverse reactions such as exfoliative dermatitis, Stevens-Johnson Syndrome (SJS), and toxic epidermal necrolysis (TEN), which can be fatal. These serious events may occur without warning. Inform patients about the signs and symptoms of serious skin reactions, and to discontinue the use of diclofenac sodium/misoprostol at the first appearance of skin rash or any other sign of hypersensitivity. Diclofenac sodium/misoprostol is contraindicated in patients with previous serious skin reactions to NSAIDs [see Contraindications (4)] .
^ Patient Counseling Information
Advise the patient to read the FDA-approved patient labeling (Medication Guide). Inform patients, families, or their caregivers of the following information before initiating therapy with diclofenac sodium/misoprostol and periodically during the course of ongoing therapy.
^ Recommended Dosage In Patients With Osteoarthritis
The recommended dosage for the treatment of osteoarthritis for maximal GI mucosal protection is diclofenac sodium/misoprostol 50 three times a day. For patients who experience intolerance, diclofenac sodium/misoprostol 75 two times a day or diclofenac sodium/misoprostol 50 two times a day can be used, but these dosages are less effective in preventing ulcers. A daily dosage of diclofenac sodium greater than 150 mg/day is not recommended. Daily doses of the components delivered with these regimens are as follows:
^ Description
Diclofenac sodium/misoprostol is a combination product containing diclofenac sodium, an NSAID with analgesic properties, and misoprostol, a gastrointestinal (GI) mucosal protective prostaglandin-1 (PGE1) analog. Diclofenac sodium/misoprostol tablets are white to off-white, round, biconvex, and approximately 11 mm in diameter. Each tablet consists of an enteric-coated core containing 50 mg (diclofenac sodium/misoprostol 50) or 75 mg (diclofenac sodium/misoprostol 75) of diclofenac sodium (equivalent to 46.39 mg or 69.58 mg of diclofenac, respectively) surrounded by an outer mantle containing 200 mcg misoprostol.
Diclofenac sodium is a phenylacetic acid derivative that is a white to off-white, virtually odorless, crystalline powder. Diclofenac sodium is freely soluble in methanol, soluble in ethanol, and practically insoluble in chloroform and in dilute acid. Diclofenac sodium is sparingly soluble in water. Its chemical formula and name are:
C 14H 10Cl 2NO 2Na [M.W. = 318.14] 2-[(2,6-dichlorophenyl) amino] benzeneacetic acid, monosodium salt.
Misoprostol is a water-soluble, viscous liquid that contains approximately equal amounts of two diastereomers. Its chemical formula and name are:
C 22H 38O 5[M.W. = 382.54] (±) methyl 11α,16-dihydroxy-16-methyl-9-oxoprost-13E-en-1-oate.
Inactive ingredients in diclofenac sodium/misoprostol include: colloidal silicon dioxide; crospovidone; hydrogenated castor oil; hypromellose; lactose; magnesium stearate; methacrylic acid copolymer; microcrystalline cellulose; povidone (polyvidone) K-30; sodium hydroxide; starch (corn); talc; triethyl citrate.
^ Clinical Trials Experience
Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.
Adverse reaction information for diclofenac sodium/misoprostol is derived from multinational controlled clinical trials in over 2,000 patients receiving diclofenac sodium/misoprostol 50 or diclofenac sodium/misoprostol 75, as well as from blinded, controlled trials of diclofenac sodium delayed-release tablets and misoprostol tablets
^ Exacerbation Of Asthma Related To Aspirin Sensitivity
A subpopulation of patients with asthma may have aspirin-sensitive asthma which may include chronic rhinosinusitis complicated by nasal polyps; severe, potentially fatal bronchospasm; and/or intolerance to aspirin and other NSAIDs. Because cross-reactivity between aspirin and other NSAIDs has been reported in such aspirin-sensitive patients, diclofenac sodium/misoprostol is contraindicated in patients with this form of aspirin sensitivity [see Contraindications (4)] . When diclofenac sodium/misoprostol is used in patients with preexisting asthma (without known aspirin sensitivity), monitor patients for changes in the signs and symptoms of asthma.
^Misoprostol
Misoprostol is a synthetic PGE1 analog with gastric antisecretory and mucosal protective properties. NSAIDs inhibit prostaglandin synthesis. A deficiency of prostaglandins within the gastric and duodenal mucosa may lead to diminishing bicarbonate and mucus secretion and may contribute to the mucosal damage caused by NSAIDs.
Misoprostol can increase bicarbonate and mucus production, but it has been shown at doses 200 mcg and above that are also antisecretory. It is therefore not possible to differentiate whether the ability of misoprostol to reduce the risk of gastric and duodenal ulcers is the result of its antisecretory effect, its mucosal protective effect, or both.
In vitro studies on canine parietal cells using titrated misoprostol acid as the ligand have led to the identification and characterization of specific prostaglandin receptors. Receptor binding is saturable, reversible, and stereo-specific. The sites have a high affinity for misoprostol, for its acid metabolite, and for other E type prostaglandins, but not for F or I prostaglandins and other unrelated compounds, such as histamine or cimetidine. Receptor-site affinity for misoprostol correlates well with an indirect index of antisecretory activity. It is likely that these specific receptors allow misoprostol taken with food to be effective topically, despite the lower serum concentrations attained.
Misoprostol, over the range of 50 mcg to 200 mcg, inhibits basal and nocturnal gastric acid secretion, and acid secretion in response to a variety of stimuli, including meals, histamine, pentagastrin, and coffee. Activity is apparent 30 minutes after oral administration and persists for at least 3 hours. In general, the effects of 50 mcg were modest and shorter-lived, and only the 200 mcg dose had substantial effects on nocturnal secretion or on histamine- and meal- stimulated secretion.
Misoprostol also produces a moderate decrease in pepsin concentration during basal conditions, but not during histamine stimulation. It has no significant effect on fasting or postprandial gastrin nor intrinsic factor output.
^ Overdosage
Manage patients with symptomatic and supportive care following an acute NSAID overdosage. There are no specific antidotes. It is advisable to contact a poison control center (1-800-222-1222) to determine the latest recommendations because strategies for the management of overdose are continually evolving.
The toxic dose of diclofenac sodium/misoprostol has not been determined. However, signs of overdosage from the components of the product have been described.
^ Hematologic Toxicity
Anemia has occurred in NSAID-treated patients. This may be due to occult or gross blood loss, fluid retention, or an incompletely described effect on erythropoiesis. If a patient treated with diclofenac sodium/misoprostol has any signs or symptoms of anemia, monitor hemoglobin or hematocrit.
NSAIDs, including diclofenac, a component of diclofenac sodium/misoprostol, may increase the risk of bleeding events. Co-morbid conditions such as coagulation disorders or concomitant use of warfarin and other anticoagulants, antiplatelet drugs (e.g., aspirin), and SSRIs and serotonin norepinephrine reuptake inhibitors (SNRIs) may increase this risk. Monitor these patients for signs of bleeding [see Drug Interactions (7)] .
^Diclofenac
The mechanism of action of diclofenac, like that of other NSAIDs, is not completely understood but involves inhibition of cyclooxygenase (COX-1 and COX-2).
Diclofenac is a potent inhibitor of prostaglandin (PG) synthesis in vitro. Diclofenac concentrations reached during therapy have produced in vivo effects. Prostaglandins sensitize afferent nerves and potentiate the action of bradykinin in inducing pain in animal models. Prostaglandins are mediators of inflammation. Because diclofenac is an inhibitor of prostaglandin synthesis, its mode of action may be due to a decrease of prostaglandins in peripheral tissues.
^ Drug Reaction With Eosinophilia And Systemic Symptoms (dress)
Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS) has been reported in patients taking NSAIDs such as diclofenac sodium/misoprostol. Some of these events have been fatal or life-threatening. DRESS typically, although not exclusively, presents with fever, rash, lymphadenopathy, and/or facial swelling. Other clinical manifestations may include hepatitis, nephritis, hematological abnormalities, myocarditis, or myositis. Sometimes symptoms of DRESS may resemble an acute viral infection. Eosinophilia is often present. Because this disorder is variable in its presentation, other organ systems not noted here may be involved. It is important to note that early manifestations of hypersensitivity, such as fever or lymphadenopathy, may be present even though rash is not evident. If such signs or symptoms are present, discontinue diclofenac sodium/misoprostol and evaluate the patient immediately.
^ Renal Impairment
Diclofenac and misoprostol are primarily excreted by the kidney .Long-term administration of NSAIDs has resulted in renal toxicity. Correct volume status in dehydrated or hypovolemic patients prior to initiating diclofenac sodium/misoprostol. Monitor renal function, especially during concomitant use of ACE inhibitors or ARBs. Also, monitor renal function in patients with hepatic impairment. Avoid the use of diclofenac sodium/misoprostol in patients with advanced renal disease. If use cannot be avoided in patients with advanced renal disease, use the lowest dosage for the shortest duration, monitor the patient’s renal function and monitor for clinical signs of worsening renal function [see Warnings and Precautions (5.7), Drug Interactions (7)and Clinical Pharmacology (12.3)] .
^Absorption
Diclofenac: Diclofenac is completely absorbed from the GI tract after oral administration under fasted condition, and peak plasma levels are achieved in 2 hours (range 1–4 hours), and the area under the plasma concentration curve (AUC) is dose-proportional within the range of 25 mg to 150 mg. Peak plasma levels are less than dose-proportional and are approximately 1.5 and 2.0 mcg/mL for 50 mg and 75 mg doses, respectively. The diclofenac in diclofenac sodium/misoprostol is in a pharmaceutical formulation that resists dissolution in the low pH of gastric fluid but allows a rapid release of drug in the higher pH environment of the duodenum. Only 50% of the absorbed dose is systemically available due to first pass metabolism (i.e., oral bioavailability is 50%).
Misoprostol: Misoprostol is rapidly absorbed following oral administration of diclofenac sodium/misoprostol, and misoprostol acid (active metabolite) reaches a maximum plasma concentration in approximately 20 minutes. 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; this effect does not appear to be clinically important.
Food decreases the multiple-dose bioavailability profile of diclofenac sodium/misoprostol 50 and diclofenac sodium/misoprostol 75.
^3 Dosage Forms And Strengths
Delayed-release tablets:
^Premature Closure Of Fetal Ductus Arteriosus
NSAIDs, including diclofenac, a component of diclofenac sodium/misoprostol, increase the risk of premature closure of the fetal ductus arteriosus at about 30 weeks of gestation and later.
^ Masking Of Inflammation And Fever
The pharmacological activity of diclofenac, a component of diclofenac sodium/misoprostol, in reducing inflammation, and possibly fever, may diminish the utility of diagnostic signs in detecting infections.
^General Pharmacokinetic Characteristics
The pharmacokinetic profiles of diclofenac and misoprostol administered as the fixed combination (diclofenac sodium/misoprostol 50 or 75) are similar to the profiles when the two drugs are administered as separate tablets (see Table 2). No pharmacokinetic interaction between the two drugs has been observed following multiple dosing. The diclofenac total exposure [area under the curve (AUC)] is dose-proportional within the range of 25 mg to 150 mg. Approximately dose-proportional increase in misoprostol exposure was also observed within the range of 200 mcg to 400 mcg. Neither diclofenac nor misoprostol accumulated in plasma following repeated doses of diclofenac sodium/misoprostol given every 12 hours under fasted conditions.
^ Pediatric Use
Safety and effectiveness of diclofenac sodium/misoprostol in pediatric patients have not been established.
^ Additional Dosage Recommendations
Diclofenac sodium/misoprostol contains misoprostol, which provides protection against gastric and duodenal ulcers [see Clinical Studies (14)] . For gastric ulcer prevention, the 200 mcg four and three times a day regimens are therapeutically equivalent, but more protective than the two times a day regimen. For duodenal ulcer prevention, the four times a day regimen is more protective than the three or two times a day regimens. However, the four times a day regimen is less well tolerated than the three times a day regimen because of usually self-limited diarrhea related to the misoprostol dose [see Adverse Reactions (6.1)] , and the two times a day regimen may be better tolerated than three times a day in some patients.
Dosages may be individualized using the separate products (misoprostol and diclofenac sodium), after which the patient may be switched to the appropriate diclofenac sodium/misoprostol dosage. If clinically indicated, misoprostol co-therapy with diclofenac sodium/misoprostol to optimize the misoprostol dose and/or frequency of administration, may be appropriate. Do not exceed a total misoprostol dose of 800 mcg/day and do not administer more than 200 mcg of misoprostol at any one time.
When concomitant use of CYP2C9 inhibitors is necessary, the maximum total daily dose of diclofenac is 100 mg per day. Do not exceed a dosage of diclofenac sodium/misoprostol 50 mg twice daily [see Drug Interactions (7)] .
For additional information, refer to the Prescribing Information for the individual products of diclofenac sodium and misoprostol.
^4 Contraindications
Diclofenac sodium/misoprostol is contraindicated in the following patients:
^Warning: Risk Of Uterine Rupture, Abortion, Premature Birth, Birth Defects; Serious Cardiovascular Events; And Serious Gastrointestinal Events
Uterine Rupture, Abortion, Premature Birth, and Birth Defects
Cardiovascular Thrombotic Events
^Principal Display Panel - Mg/ Mcg Tablet Bottle Label
^ Postmarketing Experience
The following adverse reactions have been identified during post approval of diclofenac sodium/misoprostol, diclofenac or misoprostol. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliable estimate their frequency or establish a causal relationship to drug exposure.
Body as a whole:death, fever, infection, sepsis, chills, edema.
Cardiovascular system:arrhythmia, atrial fibrillation, congestive heart failure, hypertension, hypotension, increased creatine phosphokinase (CPK), increased lactate dehydrogenase (LDH), myocardial infarction, palpitations, phlebitis, premature ventricular contractions, syncope, tachycardia, vasculitis.
Central and peripheral nervous system:coma, convulsions, hyperesthesia, hypertonia, hypoesthesia, meningitis, migraine, neuralgia, somnolence, stroke, tremor.
Congenital, familial and genetic disorders:birth defects.
Digestive:enteritis, GI bleeding, glossitis, heartburn, hematemesis, hemorrhoids, intestinal perforation, stomatitis and ulcerative stomatitis.
Female reproductive disorders:intermenstrual bleeding, leukorrhea, vaginitis, uterine cramping, uterine hemorrhage.
Hemic and lymphatic system:agranulocytosis, anemia, aplastic anemia, coagulation time increased, ecchymosis, eosinophilia, hemolytic anemia, leukocytosis, lymphadenopathy, pancytopenia, pulmonary embolism, rectal bleeding, thrombocythemia, thrombocytopenia.
Hypersensitivity:angioedema, laryngeal/pharyngeal edema, urticaria.
Liver and biliary system:abnormal hepatic function, bilirubinemia, liver failure, pancreatitis, hepatitis, jaundice.
Male reproductive disorders:impotence, perineal pain.
Metabolic and nutritional:blood urea nitrogen (BUN) increased, glycosuria, gout, hypercholesterolemia, hyperglycemia, hyperuricemia, hypoglycemia, periorbital edema, porphyria, weight changes, fluid retention.
Pregnancy, puerperium and perinatal conditions: abnormal uterine contractions, uterine rupture/perforation, retained placenta, amniotic fluid embolism, incomplete abortion, premature birth, fetal death.
Psychiatric:confusion, disorientation, dream abnormalities, hallucinations, nervousness, paranoia, psychotic reaction.
Reproductive system and breast disorders:female fertility decreased.
Respiratory system:dyspnea, pneumonia, respiratory depression.
Skin and appendages:acne, bruising, erythema multiforme, exfoliative dermatitis, pruritus ani, rash, skin ulceration, Stevens-Johnson syndrome, toxic epidermal necrolysis, cutaneous reactions (bullous eruption).
Special senses:hearing impairment, taste loss.
Renal and urinary disorders:cystitis, hematuria, interstitial nephritis, micturition frequency, nephrotic syndrome, oliguria, papillary necrosis, renal failure, glomerulonephritis membranous, glomerulonephritis minimal lesion, glomerulonephritis.
Vision:amblyopia, blurred vision, conjunctivitis, glaucoma, iritis, lacrimation abnormal, night blindness, vision abnormal.
^ How Supplied/storage And Handling
Diclofenac sodium and misoprostol delayed-release tablets are supplied as:
The dosage strengths are supplied in:
^ Geriatric Use
Geriatric patients (those 65 years of age and older), compared to younger adult patients, are at greater risk for NSAID-associated serious cardiovascular, gastrointestinal, and/or renal adverse reactions [see Warnings and Precautions (5.2, 5.3, 5.7)] . In addition, the risk of diclofenac-associated adverse reactions may be greater in geriatric patients with renal impairment or those taking concomitant ACE inhibitors or ARBs [see Drug Interactions (7)and Use in Specific Populations (8.6)] .
Avoid use of diclofenac sodium/misoprostol in geriatric patients with cardiovascular and/or renal risk factors. If use cannot be avoided, use the lowest recommended dosage for the shortest duration and monitor for cardiac and renal adverse reactions [see Dosage and Administration (2.1)] . Monitor renal function in geriatric patients during treatment with diclofenac sodium/misoprostol, especially in patients with concomitant use of ACE inhibitors or ARBs .
Of the 2,184 patients in clinical studies with diclofenac sodium/misoprostol, 557 (25.5%) were 65 years of age and over. No overall differences in effectiveness were observed between these patients and younger adult patients, and other reported clinical experience has not identified differences in effectiveness between geriatric patients and younger adult patients, but greater sensitivity of some older individuals cannot be ruled out.
No clinically meaningful differences in the pharmacokinetics of diclofenac and misoprostol were observed in geriatric patients compared to younger adult patients [see Clinical Pharmacology (12.3)].
^ Hepatotoxicity
In clinical trials with diclofenac sodium/misoprostol, meaningful elevation of alanine aminotransferase (ALT) (serum glutamic pyruvic transaminase [SGPT], more than 3 times the upper limit of the normal range [ULN]) occurred in 1.6% of 2,184 patients treated with diclofenac sodium/misoprostol and in 1.4% of 1,691 patients treated with diclofenac sodium. These increases were generally transient, and enzyme levels returned to within the normal range upon discontinuation of therapy with diclofenac sodium/misoprostol. The misoprostol component of diclofenac sodium/misoprostol does not appear to exacerbate the hepatic effects caused by the diclofenac sodium component.
In clinical trials of diclofenac-containing products, meaningful elevations (i.e., more than 3 times the ULN) of aspartate aminotransferase (AST) (serum glutamic-oxaloacetic transaminase [SGOT]) occurred in about 2% of approximately 5,700 patients at some time during diclofenac treatment (ALT was not measured in all studies).
In a large, open-label, controlled trial of 3,700 patients treated with oral diclofenac sodium for 2 to 6 months, patients were monitored first at 8 weeks and 1,200 patients were monitored again at 24 weeks. Meaningful elevations of ALT and/or AST occurred in about 4% of patients and included marked elevations (i.e., greater than 8 times the ULN) in about 1% of the 3,700 patients. In that open-label study, a higher incidence of borderline (less than 3 times the ULN), moderate (3 to 8 times the ULN), and marked (greater than 8 times the ULN) elevations of ALT or AST was observed in patients receiving diclofenac when compared to other NSAIDs. Elevations in transaminases were seen more frequently in patients with osteoarthritis than in those with rheumatoid arthritis.
Almost all meaningful elevations in transaminases were detected before patients became symptomatic. Abnormal tests occurred during the first 2 months of therapy with diclofenac in 42 of the 51 patients in all trials who developed marked transaminase elevations.
In postmarketing reports, cases of drug-induced hepatotoxicity have been reported in the first month, and in some cases, the first 2 months of therapy, but can occur at any time during treatment with diclofenac. Postmarketing surveillance has reported cases of severe hepatic reactions, including liver necrosis, jaundice, fulminant hepatitis with and without jaundice, and liver failure. Some of these reported cases resulted in fatalities or liver transplantation.
In a European retrospective population-based, case-controlled study, 10 cases of diclofenac associated drug-induced liver injury with current use compared with non-use of diclofenac were associated with a statistically significant 4-fold adjusted odds ratio of liver injury. In this particular study, based on an overall number of 10 cases of liver injury associated with diclofenac, the adjusted odds ratio increased further with female gender, doses of 150 mg or more, and duration of use for more than 90 days.
Physicians should measure transaminases at baseline and periodically in patients receiving long-term therapy with diclofenac, because severe hepatotoxicity may develop without a prodrome of distinguishing symptoms. The optimum times for making the first and subsequent transaminase measurements are not known. Based on clinical trial data and postmarketing experiences, transaminases should be monitored within 4 to 8 weeks after initiating treatment with diclofenac. However, severe hepatic reactions can occur at any time during treatment with diclofenac.
If abnormal liver tests persist or worsen, if clinical signs and/or symptoms consistent with liver disease develop, or if systemic manifestations occur (e.g., eosinophilia, rash, abdominal pain, diarrhea, dark urine, etc.), diclofenac sodium/misoprostol should be discontinued immediately.
Inform patients of the warning signs and symptoms of hepatotoxicity (e.g., nausea, fatigue, lethargy, diarrhea, pruritus, jaundice, right upper quadrant tenderness, and “flu-like” symptoms). If clinical signs and symptoms consistent with liver disease develop, or if systemic manifestations occur (e.g., eosinophilia, rash, etc.), discontinue diclofenac sodium/misoprostol immediately, and perform a clinical evaluation of the patient.
To minimize the potential risk for an adverse liver related event in patients treated with diclofenac sodium/misoprostol, the lowest effective dose should be used for the shortest duration possible. Exercise caution when prescribing diclofenac sodium/misoprostol with concomitant drugs that are known to be potentially hepatotoxic (e.g., antibiotics, anti-epileptics).
^ Gastrointestinal Bleeding, Ulceration, And Perforation
NSAIDs, including diclofenac, cause serious gastrointestinal (GI) adverse events including inflammation, bleeding, ulceration, and perforation of the esophagus, stomach, small intestine, or large intestine, which can be fatal. These serious adverse events can occur at any time, with or without warning symptoms, in patients treated with NSAIDs. Only one in five patients who develop a serious upper GI adverse event on NSAID therapy is symptomatic. Upper GI ulcers, gross bleeding, or perforation caused by NSAIDs occurred in approximately 1% of patients treated for 3 to 6 months, and in about 2% to 4% of patients treated for one year. However, even short-term NSAID therapy is not without risk.
^Excretion
Diclofenac : Diclofenac is eliminated through metabolism and subsequent urinary and biliary excretion of the glucuronide and the sulfate conjugates of the metabolites. Approximately 65% of the dose is excreted in the urine and 35% in the bile. The elimination half-life of diclofenac is approximately 2 hours. The clearance of diclofenac is approximately 350 mL/min (equivalent to 21 L/h).
Conjugates of unchanged diclofenac account for 5% to 10% of the dose excreted in the urine and for less than 5% excreted in the bile. Little or no unchanged unconjugated drug is excreted. Conjugates of the principal metabolite account for 20% to 30% of the dose excreted in the urine and for 10% to 20% of the dose excreted in the bile.
Conjugates of three other metabolites together account for 10% to 20% of the dose excreted in the urine and for small amounts excreted in the bile. The elimination half-life values for these metabolites are shorter than those for the parent drug. Urinary excretion of an additional metabolite (half-life = 80 hours) accounts for only 1.4% of the oral dose. The degree of accumulation of diclofenac metabolites is unknown. Some of the metabolites may have activity.
Misoprostol : After oral administration of radio-labeled misoprostol, approximately 70% of detected radioactivity appears in the urine. The elimination half-life is approximately 30 minutes.
^ Laboratory Monitoring
Because serious GI bleeding, hepatotoxicity, and renal injury can occur without warning symptoms or signs, consider monitoring patients on long-term NSAID treatment with a complete blood count (CBC) and a chemistry profile periodically [see Warnings and Precautions (5.3, 5.7)] .
^ Animal Toxicology
A reversible increase in the number of normal surface gastric epithelial cells occurred in the dog, rat, and mouse during long-term toxicology studies with misoprostol. No such increase has been observed in humans administered misoprostol for up to 1 year. An apparent response of the female mouse to misoprostol in long-term studies at 100 to 1000 times the human dose was hyperostosis, mainly of the medulla of sternebrae. Hyperostosis did not occur in long-term studies in the dog and rat and has not been seen in humans treated with misoprostol.
^ Heart Failure And Edema
The Coxib and traditional NSAID Trialists' Collaboration meta-analysis of randomized controlled trials demonstrated an approximately two-fold increase in hospitalizations for heart failure in COX-2 selective-treated patients and nonselective NSAID-treated patients compared to placebo-treated patients. In a Danish National Registry study of patients with heart failure, NSAID use increased the risk of MI, hospitalization for heart failure, and death.
Additionally, fluid retention and edema have been observed in some patients treated with NSAIDs. Use of diclofenac may blunt the CV effects of several therapeutic agents used to treat these medical conditions (e.g., diuretics, ACE inhibitors, or angiotensin receptor blockers [ARBs]) [see Drug Interactions (7)] .
Avoid the use of diclofenac sodium/misoprostol in patients with severe heart failure unless the benefits are expected to outweigh the risk of worsening heart failure. If diclofenac sodium/misoprostol is used in patients with severe heart failure, monitor patients for signs of worsening heart failure.
^ Anaphylactic Reactions
Diclofenac sodium/misoprostol has been associated with anaphylactic reactions in patients with and without known hypersensitivity to the individual components of diclofenac sodium and misoprostol and in patients with aspirin-sensitive asthma [see Contraindications (4)and Warnings and Precautions (5.9)] .
Seek emergency help if an anaphylactic reaction occurs.
^Oligohydramnios/neonatal Renal Impairment
Use of NSAIDs, including diclofenac, at about 20 weeks gestation or later in pregnancy may cause fetal renal dysfunction leading to oligohydramnios and, in some cases, neonatal renal impairment. These adverse outcomes are seen, on average, after days to weeks of treatment, although oligohydramnios has been infrequently reported as soon as 48 hours after NSAID initiation. Oligohydramnios is often, but not always, reversible with treatment discontinuation. Complications of prolonged oligohydramnios may, for example, include limb contractures and delayed lung maturation. In some postmarketing cases of impaired neonatal renal function, invasive procedures such as exchange transfusion or dialysis were required [see Use in Specific Populations (8.1)] .
^Elimination
Metabolism
Diclofenac : Metabolism is predominantly mediated via CYP2C9 in the liver. Five metabolites (4'hydroxy-, 5-hydroxy-, 3'-hydroxy-, 4',5-dihydroxy- and 3'-hydroxy-4'-methoxy diclofenac) have been identified. The major metabolite (4'-hydroxy-diclofenac) has very weak pharmacologic activity.
Both diclofenac and its oxidative metabolites undergo glucuronidation or sulfation followed by biliary excretion. Acylglucuronidation mediated by UGT2B7 and oxidation mediated by CYP2C8 may also play a role in diclofenac metabolism. CYP3A4 is responsible for the formation of minor metabolites, 5-hydroxy and 3'-hydroxy-diclofenac.
Misoprostol : Undergoes rapid and extensive metabolism to its biologically active metabolite, misoprostol acid.
^Specific Populations
Geriatric Patients
No differences in the pharmacokinetics of diclofenac were observed in geriatric subjects (66 to 81 years; N=10) compared to younger adult subjects (26 to 46 years; N=10) following administration of diclofenac 50 mg twice daily for 4 weeks.
Though the mean AUC value of misoprostol acid for elderly subjects was 41% higher in geriatric healthy subjects (mean age, 69.5±4.6 years, N=24) compared to younger adult healthy subjects (mean age, 25.4±4.2 years, N=24) following single dose of misoprostol 400 µg, the increase in exposure is not clinically meaningful.
In a multiple-dose crossover study of diclofenac sodium/misoprostol administered twice daily to 24 subjects aged 65 years of age and older, misoprostol did not affect the pharmacokinetics of diclofenac [see Use in Specific Populations (8.5)] .
Racial or Ethnic Groups
Pharmacokinetic differences due to race have not been identified.
Patients with Renal Impairment
In patients with renal impairment (N=5, creatinine clearance 3 to 42 mL/min) following intravenous administration of 50 mg diclofenac, AUC values and elimination rates were comparable to those in healthy subjects.
Pharmacokinetic studies with misoprostol in patients with severe renal impairment requiring hemodialysis (n=8, mean creatinine clearance 6.2±3.3 mL/min/1.73m 2) who received a single dose of 400 mcg misoprostol during a interdialytic period showed an approximate doubling of elimination half-life, C max, and AUC of misoprostol acid compared to healthy subjects [see Use in Specific Populations (8.6)] .
Patients with Hepatic Impairment
In patients with biopsy-confirmed cirrhosis or chronic active hepatitis (variably elevated transaminases and mildly elevated bilirubin, N=10), diclofenac concentrations and urinary elimination values following administration of 100 mg oral solution were comparable to those in healthy subjects.
In a study of subjects with mild to moderate hepatic impairment, mean misoprostol acid AUC and C maxshowed approximately twice high as the mean values obtained in healthy subjects. Three subjects who had the lowest antipyrine and lowest indocyanine green clearance values had the highest misoprostol acid AUC and C maxvalues.
^ Recommended Dosage In Patients With Rheumatoid Arthritis
The recommended dosage for the treatment of rheumatoid arthritis is diclofenac sodium/misoprostol 50 three or four times a day. For patients who experience intolerance, diclofenac sodium/misoprostol 75 two times a day or diclofenac sodium/misoprostol 50 two times a day can be used, but are less effective in preventing ulcers. A daily dosage of diclofenac sodium greater than 200 mg/day is not recommended. Daily doses of the components delivered with these regimens are as follows:
^6 Adverse Reactions
The following adverse reactions are discussed in greater detail in other sections of the labeling:
^7 Drug Interactions
See Table 1for clinically significant drug interactions with diclofenac and misoprostol.
^ Females And Males Of Reproductive Potential
Diclofenac sodium/misoprostol is not recommended in women of childbearing potential [see Warnings and Precautions (5.1)] . If diclofenac sodium/misoprostol is prescribed, patients must be advised of the abortifacient property and warned not to give the drug to others.
^Distribution
Diclofenac: The volume of distribution of diclofenac is approximately 0.55 L/kg. More than 99% of diclofenac is bound to plasma albumin.
Misoprostol: The plasma 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 77%) after single 200 mcg and 600 mcg misoprostol administration, respectively. The misoprostol acid concentrations in breast milk declined to <1 pg/mL at 5 hours post-dose. These data may not reflect drug level in mature milk and in a daily dosing regimen for osteoarthritis or rheumatoid arthritis.
^ Important Dosage Information
^ Hypertension
NSAIDs, including diclofenac, a component of diclofenac sodium/misoprostol, can lead to new onset of hypertension or worsening of pre-existing hypertension, either of which may contribute to the increased incidence of CV events. Patients taking angiotensin converting enzyme (ACE) inhibitors, thiazide diuretics, or loop diuretics may have impaired response to these therapies when taking NSAIDs [see Drug Interactions (7)] .
Monitor blood pressure (BP) during the initiation of NSAID treatment and throughout the course of therapy.
^Drug Interaction Studies
Diclofenac
Aspirin:When diclofenac sodium/misoprostol was administered with aspirin, the protein binding of diclofenac was reduced, although the clearance of the free diclofenac was not altered. The clinical significance of this interaction is not known. See Table 1for clinically significant drug interactions of NSAIDs with aspirin [see Drug Interactions (7)] .
Voriconazole: When a single dose diclofenac (50 mg) was coadministered with the last dose of voriconazole (400 mg every 12 hours on Day 1, followed by 200 mg every 12 hours on Day 2), the mean C maxand AUC of diclofenac were increased by 114% and 78%, respectively, when compared to diclofenac alone [see Drug Interactions (7)] .
In vitro, diclofenac interferes minimally with the protein binding of prednisolone (10% decrease in binding). Benzylpenicillin, ampicillin, oxacillin, chlortetracycline, doxycycline, cephalothin, erythromycin, and sulfamethoxazole have no influence, in vitro, on the protein binding of diclofenac in human serum.
Other drugs : In small groups of patients (7 to 10 patients/interaction study), the concomitant administration of azathioprine, gold, chloroquine, D-penicillamine, prednisolone, doxycycline or digitoxin did not significantly affect C maxand AUC of diclofenac.
Misoprostol
Diazepam : Misoprostol given for 1 week had no effect on the steady state pharmacokinetics of diazepam when the two drugs were administered 2 hours apart.
Other drugs : Pharmacokinetic studies also showed a lack of drug interaction with antipyrine or propranolol given with misoprostol.
^1 Indications And Usage
Diclofenac sodium/misoprostol is indicated for treatment of the signs and symptoms of osteoarthritis or rheumatoid arthritis in adult patients at high risk of developing NSAID-induced gastric and duodenal ulcers and their complications. For a list of factors that may increase the risk of NSAID-induced gastric and duodenal ulcers and their complications [see Warnings and Precautions (5.3)] .
^ Cardiovascular Thrombotic Events
Clinical trials of several cyclooxygenase-2 (COX-2) selective and nonselective NSAIDs of up to three years duration have shown an increased risk of serious cardiovascular (CV) thrombotic events, including myocardial infarction (MI) and stroke, which can be fatal. Based on available data, it is unclear that the risk for CV thrombotic events is similar for all NSAIDs. The relative increase in serious CV thrombotic events over baseline conferred by NSAID use appears to be similar in those with and without known CV disease or risk factors for CV disease. However, patients with known CV disease or risk factors had a higher absolute incidence of excess serious CV thrombotic events, due to their increased baseline rate. Some observational studies found that this increased risk of serious CV thrombotic events began as early as the first weeks of treatment. The increase in CV thrombotic risk has been observed most consistently at higher doses.
To minimize the potential risk for an adverse CV event in NSAID-treated patients, use the lowest effective dose for the shortest duration possible. Physicians and patients should remain alert for the development of such events, throughout the entire treatment course, even in the absence of previous CV symptoms. Patients should be informed about the symptoms of serious CV events and the steps to take if they occur.
There is no consistent evidence that concurrent use of aspirin mitigates the increased risk of serious CV thrombotic events associated with NSAID use. The concurrent use of aspirin and an NSAID, such as diclofenac, increases the risk of serious gastrointestinal (GI) events [see Warnings and Precautions (5.3)] .
^ Mechanism Of Action
Diclofenac sodium/misoprostol is a combination product containing diclofenac sodium, an NSAID with analgesic, anti-inflammatory and antipyretic properties, and misoprostol, a GI mucosal protective prostaglandin-1 (PGE1) analog.