Diclofenac sodium (topical)

7. DRUG INTERACTIONS See Table 3 for clinically significant drug interactions with diclofenac. Table 3: 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 topical solution 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 topical solution and analgesic doses of aspirin is not generally recommended because of the increased risk of bleeding [ see Warnings and Precautions (5.12) ]. Diclofenac sodium topical solution 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 topical solution 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 topical solution 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 topical solution 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 of digoxin. Intervention: During concomitant use of diclofenac sodium topical solution 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 topical solution and lithium, monitor patients for signs of lithium toxicity. Methotrexate Clinical Impact: Concomitant use of NSAIDs and methotrexate may increase the risk for methotrexate toxicity (e.g., neutropenia, thrombocytopenia, renal dysfunction) Intervention: During concomitant use of diclofenac sodium topical solution and methotrexate, monitor patients for methotrexate toxicity. Cyclosporine Clinical Impact: Concomitant use of diclofenac sodium topical solution and cyclosporine may increase cyclosporine’s nephrotoxicity. Intervention: During concomitant use of diclofenac sodium topical solution and cyclosporine, monitor patients for signs of 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 topical solution 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 salicylates is not recommended. Do not use combination therapy with diclofenac sodium topical solution and an oral NSAID unless the benefit outweighs the risk and conduct periodic laboratory evaluations. Pemetrexed Clinical Impact: Concomitant use of diclofenac sodium topical solution 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 topical solution 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 of 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. Drugs that Interfere with Hemostasis (e.g. warfarin, aspirin, SSRIs/SNRIs) : Monitor patients for bleeding who are concomitantly using diclofenac sodium topical solution with drugs that interfere with hemostasis. Concomitant use of diclofenac sodium topical solution and analgesic doses of aspirin is not generally recommended (7) ACE Inhibitors, Angiotensin Receptor Blockers (ARB) or Beta-Blockers : Concomitant use with diclofenac sodium topical solution may diminish the antihypertensive effect of these drugs. Monitor blood pressure (7) ACE Inhibitors and ARBs : Concomitant use with diclofenac sodium topical solution in elderly, volume depleted, or those with renal impairment may result in deterioration of renal function. In such high-risk patients, monitor for signs of worsening renal function (7) Diuretics : NSAIDs can reduce natriuretic effect of furosemide and thiazide diuretics. Monitor patients to assure diuretic efficacy including antihypertensive effects (7) Digoxin : Concomitant use with diclofenac sodium topical solution can increase serum concentration and prolong half-life of digoxin. Monitor serum digoxin levels (7)

8.1 Pregnancy Risk Summary Use of NSAIDs, including diclofenac sodium topical solution, 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 topical solution use between about 20 and 30 weeks of gestation, and avoid diclofenac sodium topical solution 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 topical solution, at about 30 weeks gestation or later in pregnancy increases the risk of premature closure of the fetal ductus arteriosus. Oligohydramnios/Neonatal Renal Impairment Use of NSAIDs at about 20 weeks gestation or later in pregnancy has been associated with cases of fetal renal dysfunction leading to oligohydramnios, and in some cases, neonatal renal impairment. Data from observational studies regarding other potential embryofetal risks of NSAID use in women in the first or second trimesters of pregnancy are inconclusive.

In animal reproduction studies, no evidence of malformations were observed in mice, rats, or rabbits given diclofenac 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 162 mg diclofenac sodium via diclofenac sodium topical solution, 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, 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 the Fetal…

8.3 Females and Males of Reproductive Potential Infertility Females Based on the mechanism of action, the use of prostaglandin-mediated NSAIDs, including diclofenac sodium topical solution, 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 of 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 topical solution, in women who have difficulties conceiving or who are undergoing investigation of infertility. Males Published studies in adult male rodents report that diclofenac, at clinically relevant doses, can produce adverse effects on male reproductive tissues. The impact of these findings on male fertility is not clear [See Nonclinical Toxicology (13.1) ].