Other
Cardiovascular Thrombotic Events
- Nonsteroidal anti-inflammatory drugs (NSAIDs) cause an increased risk of serious cardiovascular thrombotic events, including myocardial infarction and stroke, which can be fatal. This risk may occur early in treatment and may increase with duration of use [ see Warnings and Precautions (5.1)].
- Diclofenac Sodium is contraindicated in the setting of coronary artery bypass graft (CABG) surgery [ see Contraindications (4)and Warnings and Precautions (5.1)].
- NSAIDs cause an increased risk of serious gastrointestinal (GI) adverse events including bleeding, ulceration, and perforation of the stomach or intestines, which can be fatal. These events can occur at any time during use and without warning symptoms. Elderly patients and patients with a prior history of peptic ulcer disease and or GI bleeding are at greater risk for serious GI events [ see Warnings and Precautions (5.2)].
- Use the lowest effective dosage for the shortest possible duration.
- Avoid administration of more than one NSAID at a time.
- Avoid use in patients at higher risk unless benefits are expected to outweigh the increased risk of bleeding. For such patients, as well as those with active GI bleeding, consider alternate therapies other than NSAIDs.
- Remain alert for signs and symptoms of GI ulceration and bleeding during NSAID therapy.
- If a serious GI adverse event is suspected, promptly initiate evaluation and treatment, and discontinue diclofenac sodium until a serious GI adverse event is ruled out.
- In the setting of concomitant use of low-dose aspirin for cardiac prophylaxis, monitor patients more closely for evidence of GI bleeding [ see Drug Interactions (7)].
- Instruct patients not to apply diclofenac sodium to open skin wounds, infections, inflammations, or exfoliative dermatitis, as it may affect absorption and reduce tolerability of the drug.
- Instruct patients to wait until the area treated with diclofenac sodium is completely dry before applying sunscreen, insect repellant, lotion, moisturizer, cosmetics, or other topical medication.
- Instruct patients to minimize or avoid exposure of treated knee(s) to natural or artificial sunlight.
Gastrointestinal Bleeding, Ulceration, and Perforation
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 to 14 days following CABG surgery found an increased incidence of myocardial infarction and stroke [ see Contraindications (4)].
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 diclofenac sodium in patients with a recent MI unless the benefits are expected to outweigh the risk of recurrent CV thrombotic events. If diclofenac sodium is used in patients with a recent MI, monitor patients for signs of cardiac ischemia.
Risk Factors for GI Bleeding, Ulceration, and Perforation
Patients with a prior history of peptic ulcer disease and/or GI bleeding who used NSAIDs had a greater than 10-fold increased risk for developing a GI bleed compared to patients without these risk factors. Other factors that increase the risk of GI bleeding in patients treated with NSAIDs include longer duration of NSAID therapy; concomitant use of oral corticosteroids, aspirin, anticoagulants, or selective serotonin reuptake inhibitors (SSRIs); smoking; use of alcohol; older age; and poor general health status. Most postmarketing reports of fatal GI events occurred in elderly or debilitated patients. Additionally, patients with advanced liver disease and/or coagulopathy are at increased risk for GI bleeding.
Strategies to Minimize the GI Risks in NSAID-treated patients:
Renal Toxicity
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 an NSAID 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, dehydration, hypovolemia, heart failure, liver dysfunction, those taking diuretics and ACE inhibitors or ARBs, and the elderly. Discontinuation of NSAID therapy was usually followed by recovery to the pretreatment state.
No information is available from controlled clinical studies regarding the use of diclofenac sodium in patients with advanced renal disease. The renal effects of diclofenac sodium may hasten the progression of renal dysfunction in patients with preexisting renal disease.
Correct volume status in dehydrated or hypovolemic patients prior to initiating diclofenac sodium. Monitor renal function in patients with renal or hepatic impairment, heart failure, dehydration, or hypovolemia during use of diclofenac sodium [ see Drug Interactions (7)]. Avoid the use of diclofenac sodium in patients with advanced renal disease unless the benefits are expected to outweigh the risk of worsening renal function. If diclofenac sodium is used in patients with advanced renal disease, monitor patients for signs of worsening renal function.
Hyperkalemia
Increases in serum potassium concentration, including hyperkalemia, have been reported with use of NSAIDs, even in some patients without renal impairment. In patients with normal renal function, these effects have been attributed to a hyporeninemic-hypoaldosteronism state.
Premature Closure of Fetal Ductus Arteriosus:
Avoid use of NSAIDs, including diclofenac sodium, in pregnant women at about 30 weeks gestation and later. NSAIDs, including diclofenac sodium, increase the risk of premature closure of the fetal ductus arteriosus at approximately this gestational age.
Oligohydramnios/Neonatal Renal Impairment:
Use of NSAIDs, including diclofenac sodium, 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 diclofenac sodium use to the lowest effective dose and shortest duration possible. Consider ultrasound monitoring of amniotic fluid if diclofenac sodium treatment extends beyond 48 hours. Discontinue diclofenac sodium if oligohydramnios occurs and follow up according to clinical practice [ see Use in Specific Populations (8.1)].
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). The combination of diclofenac sodium topical solution and 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%), but no difference in elevation of liver transaminases.
Table 1 lists all adverse reactions occurring in ≥1% of patients receiving diclofenac sodium topical solution, where the rate in the diclofenac sodium topical solution group exceeded placebo, from seven controlled studies conducted in patients with osteoarthritis. Since these trials were of different durations, these percentages do not capture cumulative rates of occurrence.
| Treatment Group: | Diclofenac Sodium Topical Solution
N=911 | Topical Placebo
N=332 |
|---|---|---|
| Adverse Reaction
Preferred Term according to COSTART | N (%) | N (%) |
| Dry Skin (Application Site) | 292 (32) | 17 (5) |
| Contact Dermatitis (Application Site) | 83 (9) | 6 (2) |
| Dyspepsia | 72 (8) | 13 (4) |
| Abdominal Pain | 54 (6) | 10 (3) |
| Flatulence | 35 (4) | 1 (<1) |
| Pruritus (Application Site) | 34 (4) | 7 (2) |
| Diarrhea | 33 (4) | 7 (2) |
| Nausea | 33 (4) | 3 (1) |
| Pharyngitis | 40 (4) | 13 (4) |
| Constipation | 29 (3) | 1 (<1) |
| Edema | 26 (3) | 0 |
| Rash (Non-Application Site) | 25 (3) | 5 (2) |
| Infection | 25 (3) | 8 (2) |
| Ecchymosis | 19 (2) | 1 (<1) |
| Dry Skin (Non-Application Site) | 19 (2) | 1 (<1) |
| Contact Dermatitis, vesicles (Application Site) | 18 (2) | 0 |
| Paresthesia (Non-Application Site) | 14 (2) | 3 (<1) |
| Accidental Injury | 22 (2) | 7 (2) |
| Pruritis (Non-Application Site) | 15 (2) | 2 (<1) |
| Sinusitis | 10 (1) | 2 (<1) |
| Halitosis | 11 (1) | 1 (<1) |
| Application Site Reaction (not otherwise specified) | 11 (1) | 3 (<1) |
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).
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 diclofenac sodium treatment extends beyond 48 hours, consider monitoring with ultrasound for oligohydramnios. If oligohydramnios occurs, discontinue diclofenac sodium and follow up according to clinical practice ( see Data).
Labor or Delivery
There are no studies on the effects of diclofenac sodium topical solution during labor or delivery. In animal studies, NSAIDs, including diclofenac, inhibit prostaglandin synthesis, cause delayed parturition, and increase the incidence of stillbirth.
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
Reproductive and developmental studies in animals demonstrated that diclofenac sodium administration during organogenesis did not produce teratogenicity despite the induction of maternal toxicity and fetal toxicity in mice at oral doses up to 20 mg/kg/day (approximately 0.6 times the maximum recommended human dose [MRHD] of diclofenac sodium, 154 mg/day, based on body surface area (BSA) comparison), and in rats and rabbits at oral doses up to 10 mg/kg/day (approximately 0.6 and 1.3 times, respectively, the MRHD based on BSA comparison). Published reproductive and developmental studies of dimethyl sulfoxide (DMSO, the solvent used in diclofenac sodium) are equivocal as to potential teratogenicity.
In rats, maternally toxic doses of diclofenac were associated with dystocia, prolonged gestation, reduced fetal weights and growth, and reduced fetal survival.
Risk Summary
Based on available data, diclofenac may be present in human milk. The developmental and health benefits of breastfeeding should be considered along with the mother's clinical need for diclofenac and any potential adverse effects on the breastfed infant from the diclofenac or from the underlying maternal condition.
Data
One woman treated orally with a diclofenac salt, 150 mg/day, had a milk diclofenac level of 100 mcg/L, equivalent to an infant dose of about 0.03 mg/kg/day. Diclofenac was not detectable in breast milk in 12 women using diclofenac (after either 100 mg/day orally for 7 days or a single 50 mg intramuscular dose administered in the immediate postpartum period).
Infertility
Females
Based on the mechanism of action, the use of prostaglandin-mediated NSAIDs, including diclofenac sodium, may delay or prevent rupture of ovarian follicles, which has been associated with reversible infertility in some women. Published animal studies have shown that administration prostaglandin synthesis inhibitors has the potential to disrupt prostaglandin-mediated follicular rupture required for ovulation. Small studies in women treated with NSAIDs have also shown a reversible delay in ovulation. Consider withdrawal of NSAIDs, including diclofenac sodium, in women who have difficulties conceiving or who are undergoing investigation of infertility.
Absorption
Diclofenac systemic exposure from diclofenac sodium topical solution application (4 times daily for 1 week) was approximately 1/3 of the diclofenac systemic exposure from the diclofenac topical gel application (twice daily for 4 weeks).
Distribution
Diclofenac is more than 99% bound to human serum proteins, primarily to albumin.
Diclofenac diffuses into and out of the synovial fluid. Diffusion into the joint occurs when plasma levels are higher than those in the synovial fluid, after which the process reverses and synovial fluid levels are higher than plasma levels. It is not known whether diffusion into the joint plays a role in the effectiveness of diclofenac.
Elimination
Metabolism
Five diclofenac metabolites have been identified in human plasma and urine. The metabolites include 4'hydroxy-, 5-hydroxy-, 3'-hydroxy-, 4',5-dihydroxy- and 3'-hydroxy-4'-methoxy diclofenac. The major diclofenac metabolite, 4'-hydroxy-diclofenac, has very weak pharmacologic activity. The formation of 4'-hydroxy diclofenac is primarily mediated by CPY2C9. Both diclofenac and its oxidative metabolites undergo glucuronidation or sulfation followed by biliary excretion. Acylglucuronidation mediated by UGT2B7 and oxidation mediated by CPY2C8 may also play a role in diclofenac metabolism. CYP3A4 is responsible for the formation of minor metabolites, 5-hydroxy and 3'-hydroxy-diclofenac.
Excretion
Diclofenac is eliminated through metabolism and subsequent urinary and biliary excretion of the glucuronide and the sulfate conjugates of the metabolites.
Little or no free unchanged diclofenac is excreted in the urine.
Special Populations
Pediatric:The pharmacokinetics of diclofenac sodium topical solution has not been investigated in pediatric patients.
Race:Pharmacokinetic differences due to race have not been studied.
Drug Interaction Studies
Aspirin:When NSAIDs were administered with aspirin, the protein binding of NSAIDs were reduced, although the clearance of free NSAID 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)].
Carcinogenesis
Carcinogenicity studies in mice and rats administered diclofenac sodium as a dietary constituent for 2 years resulted in no significant increases in tumor incidence at doses up to 2 mg/kg/day corresponding to approximately 0.35- and 0.7-fold (mouse and rat, respectively) of the maximum recommended human topical dose (MRHD) of diclofenac sodium topical solution (based on apparent bioavailability and body surface area comparison).
In a dermal carcinogenicity study conducted in albino mice, daily topical applications of diclofenac sodium for two years at concentrations up to 0.035% diclofenac sodium (a 43-fold lower diclofenac sodium concentration than present in diclofenac sodium topical solution) did not increase neoplasm incidence.
In a photo-cocarcinogenicity study conducted in hairless mice, topical application of diclofenac sodium at doses up to 0.035% diclofenac sodium (a 43-fold lower diclofenac sodium concentration than present in diclofenac sodium topical solution) resulted in an earlier median time of onset of tumors.
Mutagenesis
Diclofenac was not mutagenic or clastogenic in a battery of genotoxicity tests that included the bacterial reverse mutation assay, in vitromouse lymphoma point mutation assay, chromosomal aberration studies in Chinese hamster ovarian cells in vitro, and in vivorat chromosomal aberration assay of bone marrow cells.
Impairment of Fertility
Fertility studies have not been conducted with diclofenac sodium topical solution. Diclofenac sodium administered to male and female rats at doses up to 4 mg/kg/day (1.4-fold of the MRHD of diclofenac sodium topical solution based on apparent bioavailability and body surface area comparison) did not affect fertility. Studies have not been conducted to determine the safety of DMSO on fertility.
Ocular Effects
No adverse effects were observed using indirect ophthalmoscopy after multiple-daily dermal application to rats for 26 weeks and minipigs for 52 weeks of DMSO at twice the concentration found in diclofenac sodium topical solution. Published studies of dermal or oral administration of DMSO to rabbits, dogs and pigs described refractive changes of lens curvature and cortical fibers indicative of myopic changes and/or incidences of lens opacity or discoloration when evaluated using slit-lamp biomicroscopy examination, although no ocular abnormalities were observed in rhesus monkeys during daily oral or dermal treatment with DMSO for 9 to 18 months.
Cardiovascular Thrombotic Events
Advise patients to be alert for the symptoms of cardiovascular thrombotic events, including chest pain, shortness of breath, weakness, or slurring of speech, and to report any of these symptoms to their health care provider immediately [ see Warnings and Precautions (5.1)].
Gastrointestinal Bleeding, Ulceration, and Perforation
Advise patients to report symptoms of ulcerations and bleeding, including epigastric pain, dyspepsia, melena, and hematemesis to their health care provider. In the setting of concomitant use of low-dose aspirin for cardiac prophylaxis, inform patients of the increased risk for and the signs and symptoms of GI bleeding [ see Warnings and Precautions (5.2)].
Hepatotoxicity
Inform patients of the warning signs and symptoms of hepatotoxicity (e.g., nausea, fatigue, lethargy, pruritus, diarrhea, jaundice, right upper quadrant tenderness, and "flu-like" symptoms). If these occur, instruct patients to stop diclofenac sodium and seek immediate medical therapy [ see Warnings and Precautions (5.3)].
Heart Failure and Edema
Advise patients to be alert for the symptoms of congestive heart failure including shortness of breath, unexplained weight gain, or edema and to contact their healthcare provider if such symptoms occur [ see Warnings and Precautions (5.5)].
Anaphylactic Reactions
Inform patients of the signs of an anaphylactic reaction (e.g., difficulty breathing, swelling of the face or throat). Instruct patients to seek immediate emergency help if these occur [ see Contraindications (4)and Warnings and Precautions (5.7)].
Serious Skin Reactions, including DRESS
Advise patients to stop taking diclofenac sodium immediately if they develop any type of rash or fever and to contact their healthcare provider as soon as possible [ see Warnings and Precautions (5.10, 5.9)].
Female Fertility
Advise females of reproductive potential who desire pregnancy that NSAIDs, including diclofenac sodium, may be associated with a reversible delay in ovulation [ see Use in Specific Populations (8.3)].
Fetal Toxicity
Inform pregnant women to avoid use of diclofenac sodium and other NSAIDs starting at 30 weeks gestation because of the risk of the premature closing of the fetal ductus arteriosus. If treatment with diclofenac sodium is needed for a pregnant woman between about 20 to 30 weeks gestation, advise her that she may need to be monitored for oligohydramnios, if treatment continues for longer than 48 hours [ see Warnings and Precautions (5.11)and Use in Specific Populations (8.1)].
Avoid Concomitant Use of NSAIDs
Inform patients that the concomitant use of diclofenac sodium with other NSAIDs or salicylates (e.g., diflunisal, salsalate) is not recommended due to the increased risk of gastrointestinal toxicity, and little or no increase in efficacy [ see Warnings and Precautions (5.2)and Drug Interactions (7)]. Alert patients that NSAIDs may be present in "over-the-counter" medications for treatment of colds, fever, or insomnia.
Use of NSAIDs and Low-Dose Aspirin
Inform patients not to use low-dose aspirin concomitantly with diclofenac sodium until they talk to their healthcare provider [ see Drug Interactions (7)].
Eye Exposure
Instruct patients to avoid contact of diclofenac sodium with the 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.
Prevention of Secondary Exposure
Instruct patients to avoid skin-to-skin contact between other people and the knee(s) to which diclofenac sodium was applied until the knee(s) is completely dry.
Application Site Reactions
Diclofenac sodium can cause a localized skin reaction at the application site. Advise patients to contact their physicians as soon as possible if they develop any type of localized application site rash.
Special Application Instructions
Manufactured by: Taro Pharmaceuticals Inc.
Brampton, Ontario, Canada L6T 1C1
Distributed by:
Taro Pharmaceuticals U.S.A., Inc.
Hawthorne, NY 10532
Revised: June 2021
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