NABUMETONE

Nabumetone, USP is a naphthylalkanone designated chemically as 4-(6-methoxy-2- naphthalenyl)-2-butanone. Nabumetone is a white to off-white crystalline substance. It is nonacidic and practically insoluble in water, but soluble in alcohol and most organic solvents. It has an n-octanol:phosphate buffer partition coefficient of 2400 at pH 7.4. Each tablet, for oral administration contains either 500 mg or 750 mg of nabumetone. In addition, each tablet contains the following inactive ingredients: microcrystalline cellulose, sodium starch glycolate, hydroxy propyl methyl cellulose, sodium lauryl sulphate, colloidal silicon dioxide and magnesium stearate. The 500 mg tablets also contain opadry white (Titanium dioxide, Hypromellose 3cP, Hypromellose 6cP, Macrogol and Polysorbate 80) and the 750 mg tablets contain opadry beige (Hypromellose 6cP, titanium dioxide, iron oxide yellow, iron oxide red and Macrogol). Structure

Carefully consider the potential benefits and risks of nabumetone tablets, USP and other treatment options before deciding to use nabumetone tablets. Use the lowest effective dose for the shortest duration consistent with individual patient treatment goals (see WARNINGS ). Nabumetone tablets, USP are indicated for relief of signs and symptoms of osteoarthritis and rheumatoid arthritis.

Carefully consider the potential benefits and risks of nabumetone tablets and other treatment options before deciding to use nabumetone. Use the lowest effective dose for the shortest duration consistent with individual patient treatment goals (see WARNINGS ). After observing the response to initial therapy with nabumetone tablets, the dose and frequency should be adjusted to suit an individual patient’s needs. Osteoarthritis and Rheumatoid Arthritis: The recommended starting dose is 1,000 mg taken as a single dose with or without food. Some patients may obtain more symptomatic relief from 1,500 mg to 2,000 mg per day. Nabumetone tablets can be given in either a single or twice-daily dose. Dosages greater than 2,000 mg per day have not been studied. The lowest effective dose should be used for chronic treatment (see WARNINGS , Renal Effects ). Patients weighing under 50 kg may be less likely to require dosages beyond 1,000 mg; therefore, after observing the response to initial therapy, the dose should be adjusted to meet individual patients’ requirements.

Nabumetone tablets are contraindicated in patients with known hypersensitivity to nabumetone or its excipients. Nabumetone tablets should not be given to patients who have experienced asthma, urticaria, or allergic-type reactions after taking aspirin or other NSAIDs. Severe, rarely fatal, anaphylactic-like reactions to NSAIDs have been reported in such patients (see WARNINGS , Anaphylactoid Reactions, and PRECAUTIONS , General , Preexisting Asthma ). Nabumetone tablets are contraindicated in the setting of coronary artery bypass graft (CABG) surgery (see WARNINGS ).

Adverse reaction information was derived from blinded-controlled and open-labeled clinical trials and from worldwide marketing experience. In the description below, rates of the more common events (greater than 1%) and many of the less common events (less than 1%) represent results of US clinical studies. Of the 1,677 patients who received nabumetone during US clinical trials, 1,524 were treated for at least 1 month, 1,327 for at least 3 months, 929 for at least a year, and 750 for at least 2 years. More than 300 patients have been treated for 5 years or longer. The most frequently reported adverse reactions were related to the gastrointestinal tract and included diarrhea, dyspepsia, and abdominal pain. Incidence ≥1%— Probably Causally Related Gastrointestinal: Diarrhea (14%), dyspepsia (13%), abdominal pain (12%), constipation * , flatulence * , nausea * , positive stool guaiac * , dry mouth, gastritis, stomatitis, vomiting. Central Nervous System: Dizziness * , headache * , fatigue, increased sweating, insomnia, nervousness, somnolence. Dermatologic: Pruritus * , rash * . Special Senses: Tinnitus * . Miscellaneous: Edema * ———————————————————————————————————— * Incidence of reported reaction between 3% and 9%. Reactions occurring in 1% to 3% of the patients are unmarked. Incidence < 1% — Probably Causally Related † Gastrointestinal: Anorexia, jaundice, duodenal ulcer, dysphagia, gastric ulcer, gastroenteritis, gastrointestinal bleeding, increased appetite, liver function abnormalities, melena, hepatic failure. Central Nervous System: Asthenia, agitation, anxiety, confusion, depression, malaise, paresthesia, tremor, vertigo. Dermatologic: Bullous eruptions, photosensitivity, urticaria, pseudoporphyria cutanea tarda, exfoliative dermatitis, toxic epidermal necrolysis, erythema multiforme, Stevens-Johnson syndrome, and fixed drug eruption (FDE). Cardiovascular: Vasculitis. Metabolic: Weight gain. Respiratory: Dyspnea, eosinophilic pneumonia, hypersensitivity pneumonitis, idiopathic interstitial pneumonitis. Genitourinary: Albuminuria, azotemia, hyperuricemia, interstitial nephritis, nephrotic syndrome, vaginal bleeding, renal failure. Special Senses: Abnormal vision. Hematologic/Lymphatic: Thrombocytopenia. Hypersensitivity: Anaphylactoid reaction, anaphylaxis , angioneurotic edema ———————————————————————————–––––––––––– † Adverse reactions reported only in worldwide postmarketing experience or in the literature, not seen in clinical trials, are considered rarer and are italicized. Incidence < 1% — Causal Relationship Unknown Gastrointestinal: Bilirubinuria, duodenitis, eructation, gallstones, gingivitis, glossitis, pancreatitis, rectal bleeding. Central Nervous System: Nightmares. Dermatologic: Acne, alopecia. Cardiovascular: Angina, arrhythmia, hypertension, myocardial infarction, palpitations, syncope, thrombophlebitis. Respiratory: Asthma, cough. Genitourinary: Dysuria, hematuria, impotence, renal stones. Special Senses: Taste disorder. Body as a Whole: Fever, chills. Hematologic/Lymphatic: Anemia, leukopenia, granulocytopenia. Metabolic/Nutritional: Hyperglycemia, hypokalemia, weight loss.

ACE-inhibitors: Reports suggest that NSAIDs may diminish the antihypertensive effect of ACE-inhibitors. This interaction should be given consideration in patients taking NSAIDs concomitantly with ACE-inhibitors. Aspirin: When nabumetone tablets are administered with aspirin, its protein binding is reduced, although the clearance of free nabumetone is not altered. The clinical significance of this interaction is not known; however, as with other NSAIDs, concomitant administration of nabumetone tablets and aspirin is not generally recommended because of the potential of increased adverse effects. Diuretics: Clinical studies, as well as post marketing observations, have shown that nabumetone can reduce the natriuretic effect of furosemide and thiazides in some patients. This response has been attributed to inhibition of renal prostaglandin synthesis. During concomitant therapy with NSAIDs, the patient should be observed closely for signs of renal failure (see WARNINGS, Renal Effects ), as well as to assure diuretic efficacy. Lithium: NSAIDs have produced an elevation of plasma lithium levels and a reduction in renal lithium clearance. The mean minimum lithium concentration increased 15% and the renal clearance was decreased by approximately 20%. These effects have been attributed to inhibition of renal prostaglandin synthesis by the NSAID. Thus, when NSAIDs and lithium are administered concurrently, subjects should be observed carefully for signs of lithium toxicity. Methotrexate: NSAIDs have been reported to competitively inhibit methotrexate accumulation in rabbit kidney slices. This may indicate that they could enhance the toxicity of methotrexate. Caution should be used when NSAIDs are administered concomitantly with methotrexate. Warfarin: The effects of warfarin and NSAIDs on GI bleeding are synergistic, such that users of both drugs together have a risk of serious GI bleeding higher than users of either drug alone. In vitro studies have shown that, because of its affinity for protein, 6MNA may displace other protein-bound drugs from their binding site. Caution should be exercised when administering nabumetone with warfarin since interactions have been seen with other NSAIDs. Concomitant administration of an aluminum-containing antacid had no significant effect on the bioavailability of 6MNA. When administered with food or milk, there is more rapid absorption; however, the total amount of 6MNA in the plasma is unchanged (see CLINICAL PHARMACOLOGY , Pharmacokinetics ). Carcinogenesis, Mutagenesis: In 2-year studies conducted in mice and rats, nabumetone had no statistically significant tumorigenic effect. Nabumetone did not show mutagenic potential in the Ames test and mouse micronucleus test in vivo ; however, nabumetone and 6MNA-treated lymphocytes in culture showed chromosomal aberrations at 80 mcg/mL and higher concentrations (equal to the average human exposure to nabumetone at the maximum recommended dose). Impairment of Fertility: Nabumetone did not impair fertility of male or female rats treated orally at doses of 320 mg/kg/day (1,888 mg/m 2 ) before mating. Pregnancy: Risk Summary Use of NSAIDs, including nabumetone tablets, can cause premature closure of the fetal ductus arteriosus and fetal renal dysfunction leading to oligohydramnios and, in some cases, neonatal renal impairment. Because of these risks, limit dose and duration of nabumetone tablets use between about 20 and 30 weeks of gestation and avoid nabumetone tablets use at about 30 weeks of gestation and later in pregnancy [see WARNINGS; Fetal Toxicity]. Premature Closure of Fetal Ductus Arteriosus Use of NSAIDs, including nabumetone tablets, at about 30 weeks gestation or later in pregnancy increases the risk of premature closure of the fetal ductus arteriosus. Oligohydramnios/Neonatal Renal Impairment Use of NSAIDs at about 20 weeks gestation or later in pregnancy has been associated with cases of fetal renal dysfunction leading to oligohydramnios, and in some cases, neonatal renal impairment. Data from observational studies regarding other potential embryofetal risks of NSAID use in women in the first or second trimesters of pregnancy are inconclusive. In animal reproduction studies conducted in rats and rabbits have not demonstrated evidence of developmental abnormalities. However, animal reproduction studies are not always predictive of human response. There are no adequate, wellcontrolled studies in pregnant women. Nabumetone should be used in pregnancy only if the potential benefit justifies the potential risk to the fetus. Based on animal data, prostaglandins have been shown to have an important role in endometrial vascular permeability, blastocyst implantation, and decidualization. In animal studies, administration of prostaglandin synthesis inhibitors such as nabumetone, resulted in increased pre- and post-implantation loss. Prostaglandins also have been shown to have an important role in fetal kidney development. In published animal studies, prostaglandin synthesis inhibitors have been reported to impair kidney development when administered at clinically relevant doses. The estimated background risk of major birth defects and miscarriage for the indicated population(s) is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2-4% and 15-20%, respectively. Clinical Considerations Fetal/Neonatal Adverse Reactions Premature Closure of Fetal Ductus Arteriosus: Avoid use of NSAIDs in women at about 30 weeks gestation and later in pregnancy, because NSAIDs, including nabumetone tablets, can cause premature closure of the fetal ductus arteriosus (see WARNINGS; Fetal Toxicity). Oligohydramnios/Neonatal Renal Impairment If an NSAID is necessary at about 20 weeks gestation or later in pregnancy, limit the use to the lowest effective dose and shortest duration possible. If nabumetone tablets treatment extends beyond 48 hours, consider monitoring with ultrasound for oligohydramnios. If oligohydramnios occurs, discontinue nabumetone tablets and follow up according to clinical practice (see WARNINGS; Fetal Toxicity). Data Human Data Premature Closure of Fetal Ductus Arteriosus: Published literature reports that the use of NSAIDs at about 30 weeks of gestation and later in pregnancy may cause premature closure of the fetal ductus arteriosus. Oligohydramnios/Neonatal Renal Impairment: Published studies and postmarketing reports describe maternal NSAID use at about 20 weeks gestation or later in pregnancy associated with 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. In many cases, but not all, the decrease in amniotic fluid was transient and reversible with cessation of the drug. There have been a limited number of case reports of maternal NSAID use and neonatal renal dysfunction without oligohydramnios, some of which were irreversible. Some cases of neonatal renal dysfunction required treatment with invasive procedures, such as exchange transfusion or dialysis. Methodological limitations of these postmarketing studies and reports include lack of a control group; limited information regarding dose, duration, and timing of drug exposure; and concomitant use of other medications. These limitations preclude establishing a reliable estimate of the risk of adverse fetal and neonatal outcomes with maternal NSAID use. Because the published safety data on neonatal outcomes involved mostly preterm infants, the generalizability of certain reported risks to the full-term infant exposed to NSAIDs through maternal use is uncertain. Animal Data In animal reproduction studies conducted in rats and rabbits have not demonstrated evidence of developmental abnormalities. However, animal reproduction studies are not always predictive of human response. There are no adequate, well-controlled studies in pregnant women. Nabumetone should be used in pregnancy only if the potential benefit justifies the potential risk to the fetus. Based on animal data, prostaglandins have been shown to have an important role in endometrial vascular permeability, blastocyst implantation, and decidualization. In animal studies, administration of prostaglandin synthesis inhibitors such as nabumetone, resulted in increased pre- and post-implantation loss. Prostaglandins also have been shown to have an important role in fetal kidney development. In published animal studies, prostaglandin synthesis inhibitors have been reported to impair kidney development when administered at clinically relevant doses.