FDA Label for Clofenax

View Indications, Usage & Precautions

Clofenax Product Label

The following document was submitted to the FDA by the labeler of this product Puretek Corporation. The document includes published materials associated whith this product with the essential scientific information about this product as well as other prescribing information. Product labels may durg indications and usage, generic names, contraindications, active ingredients, strength dosage, routes of administration, appearance, warnings, inactive ingredients, etc.

1 Indications And Usage



Diclofenac sodium topical solution, USP is indicated for the treatment of signs and symptoms of osteoarthritis of the knee(s) (1).


2.1 General Dosing Instructions



Use the lowest effective dosage for the shortest duration consistent with individual patient treatment goals [ see Warning and Precautions (5.2)] For the relief of the signs and symptoms of osteoarthritis of the knee(s), the recommended dose is 40 drops per knee, 4 times a day.

Apply diclofenac sodium topical solution to clean, dry skin.

To avoid spillage, dispense diclofenac sodium topical solution 10 drops at a time either directly onto the knee or first into the hand and then onto the knee. Spread diclofenac sodium topical solution evenly around front, back and sides of the knee. Repeat this procedure until 40 drops have been applied and the knee is completely covered with solution.

To treat the other knee, if symptomatic, repeat the procedure.

Application of diclofenac sodium topical solution in an amount exceeding or less than the recommended dose has not been studied and is therefore not recommended.


2.2 Special Precautions



  • Avoid showering/bathing for at least 30 minutes after the application of diclofenac sodium topical solution to the treated knee.
  • Wash and dry hands after use.
  • Do not apply diclofenac sodium topical Solution USP, to open wounds.
  • Avoid contact of diclofenac sodium topical solution with eyes and mucous membranes.
  • Do not apply external heat and/or occlusive dressings to treated knees.
  • Avoid wearing clothing over the diclofenac sodium topical solutiontreated knee(s) until the treated knee is dry.
  • Protect the treated knee(s) from natural or artificial sunlight.
  • Wait until the treated area is dry before applying sunscreen, insect repellant, lotion, moisturizer, cosmetics, or other topical medication to the same knee you have just treated with diclofenac sodium topical solution.
  • Until the treated knee(s) is completely dry, avoid skin-to-skin contact between other people and the treated knee(s).

    • Do not use combination therapy with diclofenac sodium and an oral NSAID unless the benefit outweighs the risk and conduct periodic laboratory evaluations.

3 Dosage Forms And Strengths



Diclofenac sodium topical solution USP, 1.5% w/w


4 Contraindications



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)].

5.1 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.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 [ ]. 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 (5.2)].


5.2 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.


5.3 Hepatotoxicity



In clinical trials, of oral diclofenac-containing products, meaningful elevations (i.e., more than 3 times the ULN) of AST (SGOT) were observed 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 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 3,700 patients and included marked elevations (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 then 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 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 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, use the lowest effective dose for the shortest duration possible. Exercise caution when prescribing diclofenac sodium with concomitant drugs that are known to be potentially hepatotoxic (e.g., acetaminophen, antibiotics, antiepileptics).


5.4 Hypertension



NSAIDs, including diclofenac, can lead to new onset of hypertension, or worsening of preexisting hypertension, either of which may contribute to the increased incidence of CV events. Patients taking angiotension 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) closely during the initiation of NSAID treatment and throughout the course of therapy.


5.5 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 placebotreated 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]) [ ]. 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 in patients with severe heart failure unless the benefits are expected to outweigh the risk of worsening heart failure. If diclofenac sodium is used in patients with severe heart failure, monitor patients for signs of worsening heart failure.Avoid the use of diclofenac sodium in patients with severe heart failure unless the benefits are expected to outweigh the risk of worsening heart failure. If diclofenac sodium is used in patients with severe heart failure, monitor patients for signs of worsening heart failure.


5.7 Anaphylactic Reactions



Diclofenac has been associated with anaphylactic reactions in patients with and without known hypersensitivity to diclofenac and in patients with aspirinsensitive asthma ( see Contraindications (4) and Warnings and Precautions (5.8)]. Seek emergency help if an anaphylactic reaction occurs.




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 is contraindicated in patients with this form of aspirin sensitivity [ see Contraindications (4)]. When diclofenac sodium is used in patients with preexisting asthma (without known aspirin sensitivity), monitor patients for changes in the signs and symptoms of asthma.


5.9 Serious Skin Reactions



NSAIDs, including diclofenac, 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 at the first appearance of skin rash or any other sign of hypersensitivity. Diclofenac sodium is contraindicated in patients with previous serious skin reactions to NSAIDs [ see Contraindications (4)].

Do not apply diclofenac sodium to open skin wounds, infections, inflammations, or exfoliative dermatitis, as it may affect absorption and tolerability of the drug.


5.10 Premature Closure Of Fetal Ductus Arteriosus



Diclofenac may cause premature closure of the fetal ductus arteriosus. Avoid use of NSAIDs, including diclofenac sodium, in pregnant women starting at 30 weeks of gestation (third trimester) [ see Use in Specific Populations (8.1)].


5.11 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 has any signs or symptoms of anemia, monitor hemoglobin or hematocrit.

NSAIDs, including diclofenac sodium, may increase the risk of bleeding events. Co-morbid conditions such as coagulation disorders, concomitant use of warfarin, other anticoagulants, antiplatelet agents (e.g., aspirin), serotonin reuptake inhibitors (SSRIs) and serotonin norepinephrine reuptake inhibitors (SNRIs) may increase this risk. Monitor these patients for signs of bleeding [ see Drug Interactions (7)].

The effects of diclofenac sodium on platelet function were studied in 10 healthy subjects administered 80 drops four times a day for 7 days. There was no significant change in platelet aggregation following one week of treatment [ see Clinical Pharmacology (12.4)].


5.12 Masking Of Inflammation And Fever



The pharmacological activity of diclofenac sodium in reducing inflammation, and possibly fever, may diminish the utility of diagnostic signs in detecting infections.


5.13 Laboratory Monitoring



Because serious GI bleeding, hepatotoxicity, and renal injury can occur without warning symptoms or signs, consider monitoring patients on longterm NSAID treatment with a CBC and a chemistry profile periodically [ see Warnings and Precautions (5.2, 5.3, 5.6)].


5.14 Sun Exposure



Instruct patients to avoid exposure to natural or artificial sunlight on treated knee(s) because studies in animals indicated topical diclofenac treatment resulted in an earlier onset of ultraviolet light-induced skin tumors. The potential effects of diclofenac sodium on skin response to ultraviolet damage in humans are not known.


5.15 Eye Exposure



Avoid contact of diclofenac sodium with eyes and mucosa. Advise patients that if eye contact occurs, immediately wash out the eye with water or saline and consult a physician if irritation persists for more than an hour.


5.16 Oral Nonsteroidal Anti-Inflammatory Drugs



Concomitant use of oral NSAIDs with diclofenac sodium resulted in a higher rate of rectal hemorrhage, more frequent abnormal creatinine, urea and hemoglobin. Therefore, do not use combination therapy with diclofenac sodium and an oral NSAID unless the benefit outweighs the risk and conduct periodic laboratory evaluations.


6 Adverse Reactions



The following adverse reactions are discussed in greater detail in other sections of the labeling:

6.1 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.

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.


6.2 Postmarketing Experience



In non-U.S. postmarketing surveillance, the following adverse reactions have been reported during post-approval use of diclofenac sodium topical solution. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.

Body as a Whole: abdominal pain, accidental injury, allergic reaction, asthenia, back pain, body odor, chest pain, edema, face edema, halitosis, headache, lack of drug effect, neck rigidity, pain

Cardiovascular: palpitation, cardiovascular disorder

Digestive: diarrhea, dry mouth, dyspepsia, gastroenteritis, decreased appetite, mouth ulceration, nausea, rectal hemorrhage, ulcerative stomatitis

Metabolic and Nutritional: creatinine increased

Musculoskeletal: leg cramps, myalgia

Nervous: depression, dizziness, drowsiness, lethargy, paresthesia, paresthesia at application site

Respiratory: asthma, dyspnea, laryngismus, laryngitis, pharyngitis

Skin and Appendages: At the Application Site: contact dermatitis, contact dermatitis with vesicles, dry skin, pruritus, rash; Other Skin and Appendages Adverse Reactions: eczema, rash, pruritus, skin discoloration, urticaria

Special Senses: abnormal vision, blurred vision, cataract, ear pain, eye disorder, eye pain, taste perversion


7 Drug Interactions



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 an increased 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 (5.11)]
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 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 (5.11)].
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 betablockers (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.
Intervention:During concomitant use of diclofenac sodium with diuretics, observe patients for signs of worsening renal function, in addition to assuring diuretic efficacy including antihypertensive effects [ see Warnings and Precautions (5.6)].
Digoxin
Clinical Impact:The concomitant use of diclofenac with digoxin has been reported to increase the serum concentration and prolong the half-life digoxin.
Intervention:During concomitant use of diclofenac sodium and digoxin, monitor serum digoxin levels.
Lithium
Clinical Impact:NSAIDs have produced elevations in plasma lithium levels and reductions in renal lithium clearance. The mean minimum lithium concentration increased 15%, and the renal clearance decreased by approximately 20%. This effect has been attributed to NSAID inhibition of renal prostaglandin synthesis.
Intervention:During concomitant use of diclofenac sodium and lithium, monitor patients for signs of lithium toxicity.
Methotrexate
Clinical Impact:Concomitant use of NSAIDs and methotrexate may increase the risk of methotrexate toxicity (e.g., neutropenia, thrombocytopenia, renal dysfunction).
Intervention:During concomitant use of diclofenac sodium and methotrexate, monitor patients for methotrexate toxicity.
Cyclosporine
Clinical Impact:Concomitant use of diclofenac sodium and cyclosporine may increase cyclosporine's nephrotoxicity.
Intervention:During concomitant use of diclofenac sodium and cyclosporine, monitor patients for signs or worsening renal function.
NSAIDs and Salicylates
Clinical Impact:Concomitant use of diclofenac with other NSAIDs or salicylates (e.g., diflunisal, salsalate) increases the risk of GI toxicity, with little or no increase in efficacy [ see Warnings and Precautions (5.2)].
Concomitant use of oral NSAIDs with diclofenac sodium has been evaluated in one Phase 3 controlled trial and in combination with oral diclofenac, compared to oral diclofenac alone, resulted in a higher rate of rectal hemorrhage (3% vs. less than 1%), and more frequent abnormal creatinine (12% vs. 7%), urea (20% vs. 12%) and hemoglobin (13% vs. 9%).
Intervention:The concomitant use of diclofenac with other NSAIDs or salicyclates is not recommended.
Do not use combination therapy with diclofenac sodium and an oral NSAID unless the benefit outweighs the risk and conduct periodic laboratory evaluations.
Pemetrexed
Clinical Impact:Concomitant use of diclofenac sodium and pemetrexed may increase the risk of pemetrexed-associated myelosuppression, renal, and GI toxicity (see the pemetrexed prescribing information).
Intervention:During concomitant use of diclofenac sodium and pemetrexed, in patients with renal impairment whose creatinine clearance ranges from 45 to 79 mL/min, monitor for myelosuppression, renal and GI toxicity. NSAIDs with short elimination half-lives (e.g., diclofenac, indomethacin) should be avoided for a period of two days before, the day of, and two days following administration pemetrexed.
In the absence of data regarding potential interaction between pemetrexed and NSAIDs with longer half-lives (e.g., meloxicam, nabumetone), patients taking these NSAIDs should interrupt dosing for at least five days before, the day of, and two days following pemetrexed administration.

8.1 Pregnancy



Pregnancy Category C prior to 30 weeks gestation; Category D starting 30 weeks gestation.


8.4 Pediatric Use



Safety and effectiveness in pediatric patients have not been established.


8.5 Geriatric Use



Elderly patients, compared to younger patients, are a greater risk for NSAID-associated serious cardiovascular, gastrointestinal, and/or renal adverse reactions. If the anticipated benefit for the elderly patient outweighs these potential risks, start dosing at the low end of the dosing range, and monitor patients for adverse effects [ see Warnings and Precautions (5.1, 5.2, 5.3, 5.6, 5.13)].

Of the 911 patients treated with diclofenac sodium in seven controlled, Phase 3 clinical trials, 444 subjects were 65 years of age and over. There was no age-related difference in the incidence of adverse events. Of the 793 patients treated with diclofenac sodium in one open-labeled safety trial, 334 subjects were 65 years of age and over including 107 subjects 75 and over. There was no difference in the incidence of adverse events with long-term exposure to diclofenac sodium for this elderly population.


10 Overdosage



Symptoms following acute NSAID overdosages have been typically limited to lethargy, drowsiness, nausea, vomiting, and epigastric pain, which have been generally reversible with supportive care. Gastrointestinal bleeding has occurred. Hypertension, acute renal failure, respiratory depression, and coma have occurred, but were rare. [ see Warnings and Precautions (5.1, 5.2. 5.4, 5.6)].

Manage patients with symptomatic and supportive care following an NSAID overdosage. There are no specific antidotes. Emesis is not recommended due to a possibility of aspiration and subsequent respiratory irritation by DMSO contained in diclofenac sodium. Consider activated charcoal (60 to 100 grams in adults, 1 to 2 grams per kg of body weight in pediatric patients) and/or osmotic cathartic in symptomatic patients seen within four hours of ingestion or in patients with a large overdosage (5 to 10 times the recommended dosage). Forced diuresis, alkalinization of urine, hemodialysis, or hemoperfusion may not be useful due to high protein binding.

For additional information about overdose treatment, contact a poison control center (1-800-222-1222).


11 Description



Diclofenac sodium topical solution USP, 1.5% is a nonsteroidal antiinflammatory drug, available as a clear, colorless to faintly pink-orange solution for topical application.

Diclofenac sodium topical solution contains 1.5% w/w diclofenac sodium, a benzeneacetic acid derivative that is a nonsteroidal anti-inflammatory drug (NSAID), designated chemically as 2-[(2,6-dichlorophenyl)amino]-benzeneacetic acid, monosodium salt. The molecular weight is 318.14. Its molecular formula is C 14H 10Cl 2NNaO 2 and it has the following structural formula:

Each 1 mL of solution contains 16.05 mg of diclofenac sodium. In addition, diclofenac sodium topical solution contains the following inactive ingredients: dimethyl sulfoxide USP (DMSO, 45.5% w/w), ethanol, glycerin, propylene glycol and purified water.


12.1 Mechanism Of Action



Diclofenac has analgesic, anti-inflammatory, and antipyretic properties. The mechanism of action of diclofenac sodium, 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 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.


12.3 Pharmacokinetics



After topical administration to healthy human volunteers of single and multiple maximum doses of diclofenac sodium topical solution, 40 drops (approximately 1.2 mL) to each knee (80 drops total dose), the following diclofenac pharmacokinetic parameters were obtained: (see Table 2).

Table 2: Single-Dose (80 drops) and Multiple Dose (80 drops four times daily for 7 days) Diclofenac Sodium Topical Solution Pharmacokinetic Parameters
Diclofenac Sodium
Pharmacokinetic ParametersNormal Adults [N=18]
(Age: 18 to 55 years)
Normal Adults [N=19]
(Age: 18 to 55 years)
Single DoseMultiple Dose
Four times daily for 7 days
AUC 0-t177.5 ± 72.6 ng∙h/mL695.4 ± 348.9 ng∙h/mL
AUC 0-inf196.3 ± 68.5 ng∙h/mL745.2 ± 374.7 ng∙h/mL
Plasma C max8.1 ± 5.9 ng/mL19.4 ± 9.3 ng/mL
Plasma T max (h) 11.0 ± 6.44.0 ± 6.5
Plasma t 1/2 (h) 36.7 ± 20.879.0 ± 38.1
Kel (h -1) 0.024 ± 0.0100.011 ± 0.004
CL/F (L/h)244.7 ± 84.7

Apparent total body clearance

--

14.1 Studies In Osteoarthritis Of The Knee



The use of diclofenac sodium topical solution for the treatment of the signs and symptoms of osteoarthritis of the knee was evaluated in two double-blind controlled trials conducted in the U.S. and Canada, involving patients treated with diclofenac sodium topical solution at a dose of 40 drops four times a day for 12 weeks. Diclofenac sodium topical solution was compared to topical placebo (2.3% DMSO with other excipients) and/or topical vehicle solution (45.5% w/w DMSO with other excipients), applied directly to the study knee. In both trials, diclofenac sodium topical solution treatment resulted in statistically significant clinical improvement compared to placebo and/or vehicle, in all three primary efficacy variables― pain, physical function (Western Ontario and McMaster Universities LK3.1 OA Index (WOMAC) pain and physical function dimensions) and Patient Overall Health Assessment (POHA)/Patient Global Assessment (PGA). Numerical results are summarized in Tables 3 and 4.

Table 3: Change in treatment outcomes after 12 weeks of treatment in one study of efficacy of Diclofenac Sodium Topical Solution
Efficacy VariableStudy I
Mean baseline score and mean change in efficacy variables after 12 weeks of treatment
Mean Baseline scoreDiclofenac Sodium Topical Solution
N=154
Topical placebo

placebo formulation included 2.3% DMSO


N=155
Topical vehicle

vehicle formulation included 45.5% DMSO


N=161
WOMAC pain score
(Likert 3.1, 0-20)
13-6.0-4.7-4.7
WOMAC physical function
(Likert 3.1, 0–68)
42-15.7-12.3-12.1
POHA (0–4)2.3-1.0-0.4-0.6
Table 4: Change in treatment outcomes after 12 weeks of treatment in one study of efficacy of Diclofenac Sodium Topical Solution
Efficacy VariableStudy II
Mean baseline score and mean change in efficacy variables after 12 weeks of treatment
Mean Baseline scoreDiclofenac Sodium Topical Solution
N=164
Topical vehicle

vehicle formulation included 45.5% DMSO


N=162
WOMAC pain score
(Likert 3.1, 0–20)
13-5.9-4.4
WOMAC physical function
(Likert 3.1, 0–68)
42-15.3-10.3
PGA (0–4)3.1-1.3-1.0

16 How Supplied/Storage And Handling



Diclofenac sodium topical solution USP, 1.5% w/w is supplied as a clear, colorless to slightly pink-orange solution containing 16.05 mg of diclofenac sodium per mL of solution, in a white bottle with a white dropper cap.

NDC Number & Size
Bottle 60 mLNDC 51672-1358-4
Bottle 150 mLNDC 51672-1358-2


Storage And Handling



Storage

Store at 20° to 25°C (68° to 77°F) [See USP Controlled Room Temperature].


17 Patient Counseling Information



Advise the patient to read the FDA-approved patient labeling (Medication Guide) and Instructions for Use that accompanies each prescription dispensed. Inform patients, families, or their caregivers of the following information before initiating therapy with diclofenac sodium and periodically during the course of ongoing therapy.


Spl Medguide



This Medication Guide has been approved by the U.S. Food and Drug Administration.Revised 7/2019
Medication Guide for Nonsteroidal Anti-inflammatory Drugs (NSAIDs)

What is the most important information I should know about medicines called Nonsteroidal Anti-inflammatory Drugs (NSAIDs)?

NSAIDs can cause serious side effects, including:
  • Increased risk of a heart attack or stroke that can lead to death. This risk may happen early in treatment and may increase:
  • with increasing doses of NSAIDs
  • with longer use of NSAIDs
Do not take NSAIDs right before or after a heart surgery called a "coronary artery bypass graft (CABG)."
Avoid taking NSAIDs after a recent heart attack, unless your healthcare provider tells you to. You may have an increased risk of another heart attack if you take NSAIDs after a recent heart attack.
  • Increased risk of bleeding, ulcers, and tears (perforation) of the esophagus (tube leading from the mouth to the stomach), stomach and intestines:
  • anytime during use
  • without warning symptoms
  • that may cause death
The risk of getting an ulcer or bleeding increases with:
  • past history of stomach ulcers, or stomach or intestinal bleeding with use of NSAIDs
  • taking medicines called "corticosteroids", "anticoagulants", "SSRIs", or "SNRIs"
  • increasing doses of NSAIDs
  • longer use of NSAIDs
  • smoking
  • drinking alcohol
  • older age
  • poor health
  • advanced liver disease
  • bleeding problems
NSAIDs should only be used:
  • exactly as prescribed
  • at the lowest dose possible for your treatment
  • for the shortest time needed
What are NSAIDs?
NSAIDs are used to treat pain and redness, swelling, and heat (inflammation) from medical conditions such as different types of arthritis, menstrual cramps, and other types of short-term pain.
Who should not take NSAIDs?
Do not take NSAIDs:
  • if you have had an asthma attack, hives, or other allergic reaction with aspirin or any other NSAIDs.
  • right before or after heart bypass surgery.
Before taking NSAIDs, tell your healthcare provider about all of your medical conditions, including if you:
  • have liver or kidney problems
  • have high blood pressure
  • have asthma
  • are pregnant or plan to become pregnant. Talk to your healthcare provider if you are considering taking NSAIDs during pregnancy. You should not take NSAIDs after 29 weeks of pregnancy.
  • are breastfeeding or plan to breast feed.
Tell your healthcare provider about all of the medicines you take, including prescription or over-the-counter medicines, vitamins or herbal supplements. NSAIDs and some other medicines can interact with each other and cause serious side effects. Do not start taking any new medicine without talking to your healthcare provider first.
What are the possible side effects of NSAIDs?
NSAIDs can cause serious side effects, including:
See " What is the most important information I should know about medicines called Nonsteroidal Anti-inflammatory Drugs (NSAIDs)?"
  • new or worse high blood pressure
  • liver problems including liver failure
  • low red blood cells (anemia)
  • life-threatening allergic reactions
  • heart failure
  • kidney problems including kidney failure
  • life-threatening skin reactions
  • Other side effects of NSAIDs include: stomach pain, constipation, diarrhea, gas, heartburn, nausea, vomiting, and dizziness.
Get emergency help right away if you get any of the following symptoms:
  • shortness of breath or trouble breathing
  • chest pain
  • weakness in one part or side of your body
  • slurred speech
  • swelling of the face or throat
Stop taking your NSAID and call your healthcare provider right away if you get any of the following symptoms:
  • nausea
  • more tired or weaker than usual
  • diarrhea
  • itching
  • your skin or eyes look yellow
  • indigestion or stomach pain
  • flu-like symptoms
  • vomit blood
  • there is blood in your bowel movement or it is black and sticky like tar
  • unusual weight gain
  • skin rash or blisters with fever
  • swelling of the arms, legs, hands and feet
If you take too much of your NSAID, call your healthcare provider or get medical help right away.
These are not all the possible side effects of NSAIDs. For more information, ask your healthcare provider or pharmacist about NSAIDs.
Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
Other information about NSAIDs
  • Aspirin is an NSAID but it does not increase the chance of a heart attack. Aspirin can cause bleeding in the brain, stomach, and intestines. Aspirin can also cause ulcers in the stomach and intestines.
  • Some NSAIDs are sold in lower doses without a prescription (over-the-counter). Talk to your healthcare provider before using over-the-counter NSAIDs for more than 10 days.
General information about the safe and effective use of NSAIDs
Medicines are sometimes prescribed for purposes other than those listed in a Medication Guide. Do not use NSAIDs for a condition for which it was not prescribed. Do not give NSAIDs to other people, even if they have the same symptoms that you have. It may harm them.
If you would like more information about NSAIDs, talk with your healthcare provider. You can ask your pharmacist or healthcare provider for information about NSAIDs that is written for health professionals.
Manufactured by: Taro Pharmaceuticals Inc., Brampton, Ontario, Canada L6T 1C1
Distributed by: Taro Pharmaceuticals U.S.A., Inc., Hawthorne, NY 10532
Revised: July 2019PK-6853-256For more information, call 1-866-923-4914.

Instructions For Use Diclofenac Sodium Topical Solution



Read the Medication Guide that comes with diclofenac sodium topical solution first. Be sure that you read, understand and follow these Instructions for Use before you use diclofenac sodium topical solution for the first time.

Important: For use on the skin only (topical). Do not get diclofenac sodium topical solution in your eyes, nose or mouth. Before you use Diclofenac Sodium Topical Solution:

  • Apply diclofenac sodium topical solution exactly as your healthcare provider tells you. Talk with your healthcare provider or pharmacist if you are not sure.
  • Only use diclofenac sodium topical solution to treat pain from osteoarthritis in your knee or knees.
  • Apply diclofenac sodium topical solution on clean, dry skin that does not have any cuts, infections or rashes.
  • Use diclofenac sodium topical solution 4 times each day on your knee or knees as prescribed.
  • Your total dose for each knee is 40 drops of diclofenac sodium topical solution, each time you use it.
  • If you get diclofenac sodium topical solution in your eyes, rinse your eyes right away with water or saline. Call your healthcare provider if your eyes are irritated for more than one hour.
  • Steps for using Diclofenac Sodium Topical Solution:

    Step 1.Wash your hands with soap and water before applying diclofenac sodium topical solution.

    Step 2. Put 10 drops of diclofenac sodium topical solution either on your hand or directly on your knee (see Figure A).

    Figure A

    or

    Figure B

    Figure C

    Step 3. Spread diclofenac sodium topical solution evenly on the front, back and sides of your knee (see Figures B and C). Repeat steps 2 and 3, three times so that your knee is completely covered with a total of 40 drops of diclofenac sodium topical solution.

    Step 4. If your healthcare provider has prescribed diclofenac sodium topical solution for both knees, repeat steps 2 and 3 for the other knee.

    After you use Diclofenac Sodium Topical Solution:

    • Wash your hands with soap and water right away after applying diclofenac sodium topical solution.
    • Do not:

      • touch the treated knee or allow another person to touch the knee treated with diclofenac sodium topical solution until your knee is completely dry.
      • cover your knee with clothing until your knee is completely dry.
      • put sunscreen, insect repellant, lotion, moisturizer, cosmetics, or other topical medicines on your knee until it is completely dry.
      • take a shower or a bath for at least 30 minutes after you put diclofenac sodium topical solution on your knee.
      • use heating pads or cover the treated area with bandages where you have applied diclofenac sodium topical solution.
      • use sunlamps and tanning beds. Protect your treated knee from sunlight. Wear clothes that cover your skin if you have to be in sunlight.
      • How should I store Diclofenac Sodium Topical Solution?

        • Store diclofenac sodium topical solution at room temperature between 68°F to 77°F (20°C to 25°C).
        • Keep diclofenac sodium topical solution and all medicines out of the reach of children.

          Trademarks are the property of their respective owners.
          This Instructions for Use has been approved by the U.S. Food and Drug Administration.
          Manufactured by: Taro Pharmaceuticals Inc., Brampton, Ontario, Canada L6T 1C1
          Distributed by: Taro Pharmaceuticals U.S.A., Inc. Hawthorne, NY 10532

          Revised: July 2019
          PK-6853-2
          56


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