Diflunisal

INDICATIONS AND USAGE Carefully consider the potential benefits and risks of diflunisal tablets and other treatment options before deciding to use diflunisal tablets. Use the lowest effective dose for the shortest duration consistent with individual patient treatment goals (see WARNINGS ). Diflunisal tablets are indicated for acute or long-term use for symptomatic treatment of the following: 1. Mild to moderate pain 2. Osteoarthritis 3. Rheumatoid arthritis

DOSAGE AND ADMINISTRATION Carefully consider the potential benefits and risks of diflunisal tablets and other treatment options before deciding to use diflunisal tablets. 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 diflunisal tablets, the dose and frequency should be adjusted to suit an individual patient's needs. Concentration-dependent pharmacokinetics prevail when diflunisal is administered; a doubling of dosage produces a greater than doubling of drug accumulation. The effect becomes more apparent with repetitive doses. For mild to moderate pain, an initial dose of 1000 mg followed by 500 mg every 12 hours is recommended for most patients. Following the initial dose, some patients may require 500 mg every 8 hours. A lower dosage may be appropriate depending on such factors as pain severity, patient response, weight, or advanced age; for example, 500 mg initially, followed by 250 mg every 8 to 12 hours. For osteoarthritis and rheumatoid arthritis, the suggested dosage range is 500 mg to 1000 mg daily in two divided doses. The dosage of diflunisal may be increased or decreased according to patient response. Maintenance doses higher than 1500 mg a day are not recommended. Tablets should be swallowed whole, not crushed or chewed.

CONTRAINDICATIONS Diflunisal tablets are contraindicated in patients with known hypersensitivity to diflunisal or the excipients (see DESCRIPTION ). Diflunisal 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/analphylactoid reactions to NSAIDs have been reported in such patients (see WARNINGS, Anaphylactic/Anaphylactoid Reactions and PRECAUTIONS, Preexisting Asthma ). Diflunisal tablets are contraindicated in the setting of coronary artery bypass graft (CABG) surgery (see WARNINGS ).

WARNINGS Cardiovascular Effects Cardiovascular Thrombotic Events Clinical trials of several 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 diflunisal, increases the risk of serious gastrointestinal (GI) events (see WARNINGS ) . Status Post Coronary Artery Bypass Graft (CABG) Surgery Two large, controlled clinical trials of a COX-2 selective NSAID for the treatment of pain in the first 10–14 days following CABG surgery found an increased incidence of myocardial infarction and stroke. NSAIDs are contraindicated in the setting of CABG (see CONTRAINDICATIONS ) . Post-MI Patients Observational studies conducted in the Danish National Registry have demonstrated that patients treated with NSAIDs in the post-MI period were at increased risk of reinfarction, CV-related death, and all-cause mortality beginning in the first week of treatment. In this same cohort, the incidence of death in the first year post MI was 20 per 100 person years in NSAID-treated patients compared to 12 per 100 person years in non-NSAID exposed patients. Although the absolute rate of death declined somewhat after the first year post-MI, the increased relative risk of death in NSAID users persisted over at least the next four years of follow-up. Avoid the use of diflunisal tablets in patients with a recent MI unless the benefits are expected to outweigh the risk of recurrent CV thrombotic events. If diflunisal tablets is used in patients with a recent MI, monitor patients for signs of cardiac ischemia. Hypertension NSAIDs, including diflunisal tablets, can lead to onset of new hypertension or worsening of preexisting hypertension, either of which may contribute to the increased incidence of CV events. Patients taking thiazides or loop diuretics may have impaired response to these therapies when taking NSAIDs. NSAIDs, including diflunisal tablets, should be used with caution in patients with hypertension. Blood pressure (BP) should be monitored closely during the initiation of NSAID treatment and throughout the course of therapy. 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 diflunisal 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 ). Avoid the use of Diflunisal Tablets in patients with severe heart failure unless the benefits are expected to outweigh the risk of worsening heart failure. If Diflunisal Tablets is used in patients with severe heart failure, monitor patients for signs of worsening heart failure. Gastrointestinal Effects – Risk of Ulceration, Bleeding and Perforation NSAIDs, including diflunisal tablets, can cause serious gastrointestinal (GI) adverse events including inflammation, bleeding, ulceration, and perforation of the 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 occur in approximately 1% of patients treated for 3 to 6 months, and in about 2 to 4% of patients treated for one year. These trends continue with longer duration of use, increasing the likelihood of developing a serious GI event at some time during the course of therapy. However, even short-term therapy is not without risk. NSAIDs should be prescribed with extreme caution in those with a prior history of ulcer disease or gastrointestinal bleeding. Patients with a prior history of peptic ulcer disease and/or gastrointestinal bleeding who use NSAIDs have a greater than 10 fold increased risk for developing a GI bleed compared to patients with neither of these risk factors. Other factors that increase the risk for GI bleeding in patients treated with NSAIDs include concomitant use of oral corticosteroids or anticoagulants, longer duration of NSAID therapy, smoking, use of alcohol, older age, and poor general health status. Most spontaneous reports of fatal GI events are in elderly or debilitated patients and therefore, special care should be taken in treating this population. To minimize the potential risk for an adverse GI event in patients treated with an NSAID, the lowest effective dose should be used for the shortest possible duration. Patients and physicians should remain alert for signs and symptoms of GI ulceration and bleeding during NSAID therapy and promptly initiate additional evaluation and treatment if a serious GI adverse event is suspected. This should include discontinuation of the NSAID until a serious GI adverse event is ruled out. For high risk patients, alternate therapies that do not involve NSAIDs should be considered. Renal Effects Long-term administration of NSAIDs has resulted in renal papillary necrosis and other renal injury. Renal toxicity has also been seen in patients in whom renal prostaglandins have a compensatory role in the maintenance of renal perfusion. In these patients, administration of a non-steroidal anti-inflammatory drug may cause a dose-dependent reduction in prostaglandin formation and, secondarily, in renal blood flow, which may precipitate overt renal decompensation. Patients at greatest risk of this reaction are those with impaired renal function, heart failure, liver dysfunction, those taking diuretics and ACE inhibitors, patients who are volume depleted, and the elderly. Discontinuation of NSAID therapy is usually followed by recovery to the pretreatment state. Advanced Renal Disease No information is available from controlled clinical studies regarding the use of diflunisal tablets in patients with advanced renal disease. Therefore, treatment with diflunisal tablets is not recommended in these patients with advanced renal disease. If diflunisal tablet therapy must be initiated, close monitoring of the patient's renal function is advisable. Anaphylactic/Anaphylactoid Reactions As with other NSAIDs, anaphylactic/anaphylactoid reactions may occur in patients without known prior exposure to diflunisal tablets. Diflunisal tablets should not be given to patients with the aspirin triad. This symptom complex typically occurs in asthmatic patients who experience rhinitis with or without nasal polyps, or who exhibit severe, potentially fatal bronchospasm after taking aspirin or other NSAIDs (see CONTRAINDICATIONS and PRECAUTIONS, Preexisting Asthma ). Emergency help should be sought in cases where an anaphylactic/anaphylactoid reaction occurs. Serious Skin Reactions NSAIDs, including diflunisal, can cause serious skin adverse reactions such as exfoliative dermatitis, Stevens-Johnson syndrome (SJS), and toxic epidermal necrolysis (TEN), which can be fatal. NSAIDs can also cause fixed drug eruption (FDE). FDE may present as a more severe variant known as generalized bullous fixed drug eruption (GBFDE), which can be life-threatening. These serious events may occur without warning. Inform patients about the signs and symptoms of serious skin reactions, and to discontinue the use of diflunisal tablets at the first appearance of skin rash or any other sign of hypersensitivity. Diflunisal tablets are contraindicated in patients with previous serious skin reactions to NSAIDs (see CONTRAINDICATIONS ). 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 diflunisal tablets. 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, haematological 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 diflunisal tablets and evaluate the patient immediately. Hypersensitivity Syndrome A potentially life-threatening, apparent hypersensitivity syndrome has been reported. This multisystem syndrome includes constitutional symptoms (fever, chills), and cutaneous findings (see ADVERSE REACTIONS, Dermatologic ). It may also include involvement of major organs (changes in liver function, jaundice, leukopenia, thrombocytopenia, eosinophilia, disseminated intravascular coagulation, renal impairment, including renal failure), and less specific findings (adenitis, arthralgia, myalgia, arthritis, malaise, anorexia, disorientation). If evidence of hypersensitivity occurs, therapy with diflunisal tablets should be discontinued. Fetal Toxicity Premature Closure of Fetal Ductus Arteriosus: Avoid use of NSAIDs, including diflunisal tablets, in pregnant women at about 30 weeks gestation and later. NSAIDs including diflunisal tablets, increase the risk of premature closure of the fetal ductus arteriosus at approximately this gestational age. Oligohydramnios/Neonatal Renal Impairment: Use of NSAIDs, including diflunisal tablets, 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. If NSAID treatment is necessary between about 20 weeks and 30 weeks gestation, limit diflunisal tablets use to the lowest effective dose and shortest duration possible. Consider ultrasound monitoring of amniotic fluid if diflunisal tablets treatment extends beyond 48 hours. Discontinue diflunisal tablets if oligohydramnios occurs and follow up according to clinical practice [ see PRECAUTIONS; Pregnancy ] .

ADVERSE REACTIONS The adverse reactions observed in controlled clinical trials encompass observations in 2,427 patients. Listed below are the adverse reactions reported in the 1,314 of these patients who received treatment in studies of two weeks or longer. Five hundred thirteen patients were treated for at least 24 weeks, 255 patients were treated for at least 48 weeks, and 46 patients were treated for 96 weeks. In general, the adverse reactions listed below were 2 to 14 times less frequent in the 1,113 patients who received short-term treatment for mild to moderate pain. Incidence Greater Than 1% Gastrointestinal The most frequent types of adverse reactions occurring with diflunisal are gastrointestinal: these include nausea*, vomiting, dyspepsia*, gastrointestinal pain*, diarrhea*, constipation, and flatulence. Psychiatric Somnolence, insomnia. Central Nervous System Dizziness. Special Senses Tinnitus. Dermatologic Rash*. Miscellaneous Headache*, fatigue/tiredness. * Incidence between 3% and 9%. Those reactions occurring in 1% to 3% are not marked with an asterisk. Incidence Less Than 1 in 100 The following adverse reactions, occurring less frequently than 1 in 100, were reported in clinical trials or since the drug was marketed. The probability exists of a causal relationship between diflunisal and these adverse reactions. Dermatologic Erythema multiforme, exfoliative dermatitis, Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), fixed drug reaction (FDE), urticaria, pruritus, sweating, dry mucous membranes, stomatitis, and photosensitivity. Gastrointestinal Peptic ulcer, gastrointestinal bleeding, anorexia, eructation, gastrointestinal perforation, gastritis. Liver function abnormalities; jaundice, sometimes with fever; cholestasis; hepatitis. Hematologic Thrombocytopenia; agranulocytosis; hemolytic anemia. Genitourinary Dysuria; renal impairment, including renal failure; interstitial nephritis; hematuria; proteinuria. Psychiatric Nervousness, depression, hallucinations, confusion, disorientation. Central Nervous System Vertigo; light-headedness; paresthesias. Special Senses Transient visual disturbances including blurred vision. Hypersensitivity Reactions Acute anaphylactic reaction with bronchospasm; angioedema; flushing. Hypersensitivity vasculitis. Hypersensitivity syndrome (see PRECAUTIONS ). Miscellaneous Asthenia, edema. Causal Relationship Unknown Other reactions have been reported in clinical trials or since the drug was marketed, but occurred under circumstances where a causal relationship could not be established. However, in these rarely reported events, that possibility cannot be excluded. Therefore, these observations are listed to serve as alerting information to physicians. Respiratory Dyspnea. Cardiovascular Palpitation, syncope. Musculoskeletal Muscle cramps. Genitourinary Nephrotic syndrome. Special Senses Hearing loss. Miscellaneous Chest pain. A rare occurrence of fulminant necrotizing fasciitis, particularly in association with Group A β -hemolytic streptococcus, has been described in persons treated with non-steroidal anti-inflammatory agents, including diflunisal, sometimes with fatal outcome (see also PRECAUTIONS, General ). Potential Adverse Effects In addition, a variety of adverse effects not observed with diflunisal in clinical trials or in marketing experience, but reported with other non-steroidal analgesic/anti-inflammatory agents should be considered potential adverse effects of diflunisal.

Fetal Toxicity Premature Closure of Fetal Ductus Arteriosus: Avoid use of NSAIDs, including diflunisal tablets, in pregnant women at about 30 weeks gestation and later. NSAIDs including diflunisal tablets, increase the risk of premature closure of the fetal ductus arteriosus at approximately this gestational age. Oligohydramnios/Neonatal Renal Impairment: Use of NSAIDs, including diflunisal tablets, 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. If NSAID treatment is necessary between about 20 weeks and 30 weeks gestation, limit diflunisal tablets use to the lowest effective dose and shortest duration possible. Consider ultrasound monitoring of amniotic fluid if diflunisal tablets treatment extends beyond 48 hours. Discontinue diflunisal tablets if oligohydramnios occurs and follow up according to clinical practice [ see PRECAUTIONS; Pregnancy ] .