Lixofen

Diclofenac sodium topical solution, USP is indicated for the treatment of signs and symptoms of osteoarthritis of the knee(s) (1). Diclofenac sodium topical solution is a nonsteroidal anti-inflammatory drug indicated for the treatment of signs and symptoms of osteoarthritis of the knee(s). ( 1 )

Diclofenac sodium topical solution, USP is contraindicated in the following patients: Known hypersensitivity (e.g., anaphylactic reactions and serious skin reactions) to diclofenac or any components of the drug product [see Warnings and Precautions (5.7 , 5.9) ]. History of asthma, urticaria, or other allergic-type reactions after taking aspirin or other NSAIDs. Severe, sometimes fatal, anaphylactic reactions to NSAIDs have been reported in such patients [ see Warnings and Precautions (5.7 , 5.8) ] .

In the setting of coronary artery bypass graft (CABG) surgery [ see Warnings and Precautions (5.1) ]. Known hypersensitivity to diclofenac or any components of the drug product. ( 4 ) History of asthma, urticaria, or allergic-type reactions after taking aspirin or other NSAIDs. ( 4 ) In the setting of CABG surgery ( 4 )

Hepatotoxicity: Inform patients of warning signs and symptoms of hepatotoxicity. Discontinue if abnormal liver tests persist or worsen or if clinical signs and symptoms of liver disease develop ( 5.3 ) Hypertension: Patients taking some antihypertensive medications may have impaired response to these therapies when taking NSAIDs. Monitor blood pressure ( 5.4 , 7 ) Heart Failure and Edema: Avoid use of diclofenac sodium in patients with severe heart failure unless benefits are expected to outweigh risk of worsening heart failure ( 5.5 ) Renal Toxicity: Monitor renal function in patients with renal or hepatic impairment, heart failure, dehydration, or hypovolemia.

Avoid use of diclofenac sodium in patients with advanced renal disease unless benefits are expected to outweigh risk of worsening renal function ( 5.6 ) Anaphylactic Reactions: Seek emergency help if an anaphylactic reaction occurs ( 5.7) Exacerbation of Asthma Related to Aspirin Sensitivity: Diclofenac sodium is contraindicated in patients with aspirin-sensitive asthma. Monitor patients with preexisting asthma (without aspirin sensitivity) ( 5.8 ) Serious Skin Reactions: Discontinue diclofenac sodium at first appearance of skin rash or other signs of hypersensitivity ( 5.9 ) Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS): Discontinue and evaluate clinically ( 5.10 ).

Fetal Toxicity: Limit use of NSAIDs, including diclofenac sodium, between about 20 to 30 weeks in pregnancy due to the risk of oligohydramnios/fetal renal dysfunction. Avoid use of NSAIDs in women at about 30 weeks gestation and later in pregnancy due to the risks of oligohydramnios/fetal renal dysfunction and premature closure of the fetal ductus arteriosus ( 5.11 , 8.1 ). Hematologic Toxicity: Monitor hemoglobin or hematocrit in patients with any signs or symptoms of anemia ( 5.12 , 7 ) Exposure to light: Avoid exposure of treated knee(s) to natural or artificial sunlight.

( 5.15 ) Eye Contact: Avoid contact of diclofenac sodium with eyes and mucosa. ( 5.16 ) Oral Nonsteroidal Anti-inflammatory Drugs: Avoid concurrent use with oral NSAIDs. ( 5.17 )

5.1Cardiovascular 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.

See Table 2 for clinically significant drug interactions with diclofenac. Table 2: Clinically Significant Drug Interactions with Diclofenac Drugs That Interfere with Hemostasis Clinical Impact: Diclofenac and anticoagulants such as warfarin have a synergistic effect on bleeding. The concomitant use of diclofenac and anticoagulants have increased the risk of serious bleeding compared to the use of either drug alone. Serotonin release by platelets plays an important role in hemostasis.

Case-control and cohort epidemiological studies showed that concomitant use of drugs that interfere with serotonin reuptake and an NSAID may potentiate the risk of bleeding more than an NSAID alone. Intervention: Monitor patients with concomitant use of diclofenac sodium with anticoagulants (e.g., warfarin), antiplatelet agents (e.g., aspirin), selective serotonin reuptake inhibitors (SSRIs), and serotonin norepinephrine reuptake inhibitors (SNRIs) for signs of bleeding [see Warnings and Precautions (5.12) ] Aspirin Clinical Impact: Controlled clinical studies showed that the concomitant use of NSAIDs and analgesic doses of aspirin does not produce any greater therapeutic effect than the use of NSAIDs alone.

In a clinical study, the concomitant use of an NSAID and aspirin was associated with a significantly increased incidence of GI adverse reactions as compared to use of the NSAID alone [see Warnings and Precautions (5.2) ] Intervention: Concomitant use of diclofenac sodium and analgesic doses of aspirin is not generally recommended because of the increased risk of bleeding [see Warnings and Precautions (5.12) ] . Diclofenac sodium is not a substitute for low dose aspirin for cardiovascular protection.

ACE Inhibitors, Angiotensin Receptor Blockers, and Beta-Blockers Clinical Impact: NSAIDs may diminish the antihypertensive effect of angiotensin converting enzyme (ACE) inhibitors, angiotensin receptor blockers (ARBs), or beta-blockers (including propranolol). In patients who are elderly, volume-depleted (including those on diuretic therapy), or have renal impairment, co-administration of an NSAID with ACE inhibitors or ARBs may result in deterioration of renal function, including possible acute renal failure.

These effects are usually reversible. Intervention: During concomitant use of diclofenac sodium and ACE-inhibitors, ARBs, or beta-blockers, monitor blood pressure to ensure that the desired blood pressure is obtained. During concomitant use of diclofenac sodium and ACE-inhibitors or ARBs in patients who are elderly, volume-depleted, or have impaired renal function, monitor for signs of worsening renal function [see Warnings and Precautions (5.6) ].

When these drugs are administered concomitantly, patients should be adequately hydrated. Assess renal function at the beginning of the concomitant treatment and periodically thereafter. Diuretics Clinical Impact: Clinical studies, as well as post-marketing observations, showed that NSAIDs reduced the natriuretic effect of loop diuretics (e.g., furosemide) and thiazide diuretics in some patients. This effect has been attributed to the NSAID inhibition of renal prostaglandin synthesis.

8.1 Pregnancy Risk Summary Use of NSAIDs, including diclofenac sodium, 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 diclofenac sodium use between about 20 and 30 weeks of gestation, and avoid diclofenac sodium use at about 30 weeks of gestation and later in pregnancy ( see Clinical Considerations , Data ).

Premature Closure of Fetal Ductus Arteriosus Use of NSAIDs, including diclofenac sodium, 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 embryo-fetal risks of NSAID use in women in the first or second trimesters of pregnancy are inconclusive. Published reproductive and developmental studies of dimethyl sulfoxide (DMSO, the solvent used in Diclofenac Sodium) are equivocal as to potential teratogenicity. In animal reproduction studies, no evidence of teratogenicity was observed in mice, rats, or rabbits given diclofenac daily during the period of organogenesis at doses up to approximately 0.6, 0.6, and 1.3 times, respectively, the maximum recommended human dose (MRHD) of diclofenac sodium, despite the presence of maternal and fetal toxicity at these doses [see Data ] .

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 diclofenac sodium, 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 to 4% and 15 to 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 diclofenac sodium, can cause premature closure of the fetal ductus arteriosus ( see Data ).

The following adverse reactions are discussed in greater detail in other sections of the labeling: Cardiovascular Thrombotic Events [ see Warnings and Precautions (5.1) ] GI Bleeding, Ulceration and Perforation [ see Warnings and Precautions (5.2) ] Hepatotoxicity [ see Warnings and Precautions (5.3) ] Hypertension [ see Warnings and Precautions (5.4) ] Heart Failure and Edema [ see Warnings and Precautions (5.5) ] Renal Toxicity and Hyperkalemia [ see Warnings and Precautions (5.6) ] Anaphylactic Reactions [ see Warnings and Precautions (5.7) ] Serious Skin Reactions [ see Warnings and Precautions (5.9) ] Hematologic Toxicity [ see Warnings and Precautions (5.12) ] The most common adverse reactions with diclofenac sodium topical solution are application site reactions.

( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Taro Pharmaceuticals U.S.A., Inc. at 1-866-923-4914 or the FDA at 1-800-FDA-1088 or www.fda.gov/medwatch .

6.1Clinical 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. The data described below reflect exposure to diclofenac sodium topical solution of 911 patients treated between 4 and 12 weeks (mean duration of 49 days) in seven Phase 3 controlled trials, as well as exposure of 793 patients treated in an open-label study, including 463 patients treated for at least 6 months, and 144 patients treated for at least 12 months.

The population mean age was approximately 60 years, 89% of patients were Caucasians, 64% were females, and all patients had primary osteoarthritis. The most common adverse events with diclofenac sodium topical solution were application site skin reactions. These events were the most common reason for withdrawing from the studies. Application Site Reactions In controlled trials, the most common treatment-related adverse events in patients receiving diclofenac sodium topical solution were application site skin reactions.

Application site reactions were characterized by one or more of the following: dryness, erythema, induration, vesicles, paresthesia, pruritus, vasodilation, acne, and urticaria. The most frequent of these reactions were dry skin (32%), contact dermatitis characterized by skin erythema and induration (9%), contact dermatitis with vesicles (2%) and pruritus (4%). In one controlled trial, a higher rate of contact dermatitis with vesicles (4%) was observed after treatment of 152 subjects with the combination of diclofenac sodium topical solution and oral diclofenac.

In the open label uncontrolled long-term safety study, contact dermatitis occurred in 13% and contact dermatitis with vesicles in 10% of patients, generally within the first 6 months of exposure, leading to a withdrawal rate for an application site event of 14%. Adverse Events Common to the NSAID Class In controlled trials, subjects treated with diclofenac sodium topical solution experienced some adverse events associated with the NSAID class more frequently than subjects using placebo (constipation, diarrhea, dyspepsia, nausea, flatulence, abdominal pain, edema; see Table 1 ).