Naproxen

7 DRUG INTERACTIONS See Table 1 for clinically significant drug interactions with naproxen. Table 1: Clinically Significant Drug Interactions with naproxen Drugs That Interfere with Hemostasis Clinical Impact: Naproxen and anticoagulants such as warfarin have a synergistic effect on bleeding. The concomitant use of naproxen 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 naproxen 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: A pharmacodynamic (PD) study has demonstrated an interaction in which lower dose naproxen (220mg/day or 220mg twice daily) interfered with the antiplatelet effect of low-dose immediate-release aspirin, with the interaction most marked during the washout period of naproxen ( see 12.2 Pharmacodynamics ). There is reason to expect that the interaction would be present with prescription doses of naproxen or with enteric-coated low-dose aspirin; however, the peak interference with aspirin function may be later than observed in the PD study due to the longer washout period. 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: Because there may be an increased risk of cardiovascular events following discontinuation of naproxen due to the interference with the antiplatelet effect of aspirin during the washout period, for patients taking low-dose aspirin for cardioprotection who require intermittent analgesics, consider use of an NSAID that does not interfere with the antiplatelet effect of aspirin, or non-NSAID analgesics where appropriate. Concomitant use of naproxen and analgesic doses of aspirin is not generally recommended because of the increased risk of bleeding [ see Warnings and Precautions (5.12) ]. Naproxen Tablets are not substitutes 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 naproxen and ACE-inhibitors, ARBs, or beta-blockers, monitor blood pressure to ensure that the desired blood pressure is obtained. During concomitant use of naproxen 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 naproxen 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 naproxen with digoxin has been reported to increase the serum concentration and prolong the half-life of digoxin Intervention: During concomitant use of naproxen 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 naproxen 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 naproxen and methotrexate, monitor patients for methotrexate toxicity. Cyclosporine Clinical Impact: Concomitant use of naproxen and cyclosporine may increase cyclosporine’s nephrotoxicity. Intervention: During concomitant use of naproxen and cyclosporine, monitor patients for signs of worsening renal function. NSAIDs and Salicylates Clinical Impact: Concomitant use of naproxen 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) ]. Intervention: The concomitant use of naproxen with other NSAIDs or salicylates is not recommended. Pemetrexed Clinical Impact: Concomitant use of naproxen and pemetrexed may increase the risk of pemetrexed-associated myelosuppression, renal, and GI toxicity (see the pemetrexed prescribing information). Intervention: During concomitant use of naproxen and pemetrexed, in patients with renal impairment whose creatinine clearance ranges from 45 mL/min 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. Antacids and Sucralfate Clinical Impact: Concomitant administration of some antacids (magnesium oxide or aluminum hydroxide) and sucralfate can delay the absorption of naproxen. Intervention: Concomitant administration of antacids such as magnesium oxide or aluminum hydroxide, and sucralfate with naproxen is not recommended. Cholestyramine Clinical Impact: Concomitant administration of cholestyramine can delay the absorption of naproxen. Intervention: Concomitant administration of cholestyramine with naproxen is not recommended. Probenecid Clinical Impact: Probenecid given concurrently increases naproxen anion plasma levels and extends its plasma half-life significantly. Intervention: Patients simultaneously receiving naproxen and probenecid should be observed for adjustment of dose if required. Other albumin-bound drugs Clinical Impact: Naproxen is highly bound to plasma albumin; it thus has a theoretical potential for interaction with other albumin-bound drugs such as coumarin-type anticoagulants, sulphonylureas, hydantoins, other NSAIDs, and aspirin. Intervention: Patients simultaneously receiving naproxen and a hydantoin, sulphonamide or sulphonylurea should be observed for adjustment of dose if required. Drug/Laboratory Test Interactions Bleeding times Clinical Impact: Naproxen may decrease platelet aggregation and prolong bleeding time. Intervention: This effect should be kept in mind when bleeding times are determined. Porter-Silber test Clinical Impact: The administration of naproxen may result in increased urinary values for 17-ketogenic steroids because of an interaction between the drug and/or its metabolites with m-di-nitrobenzene used in this assay. Intervention: Although 17-hydroxy-corticosteroid measurements (Porter-Silber test) do not appear to be artifactually altered, it is suggested that therapy with naproxen be temporarily discontinued 72 hours before adrenal function tests are performed if the Porter-Silber test is to be used. Urinary assays of 5-hydroxy indoleacetic acid (5HIAA) Clinical Impact: Naproxen may interfere with some urinary assays of 5-hydroxy indoleacetic acid (5HIAA). Intervention: This effect should be kept in mind when urinary 5-hydroxy indoleacetic acid is determined. Drugs that Interfere with Hemostasis (e.g. warfarin, aspirin, SSRIs/SNRIs) : Monitor patients for bleeding who are concomitantly taking Naproxen Tablets with drugs that interfere with hemostasis. Concomitant use of Naproxen Tablets and analgesic doses of aspirin is not generally recommended. (7) ACE inhibitors, Angiotensin Receptor Blockers (ARB), or Beta-Blockers : Concomitant use with Naproxen Tablets may diminish the antihypertensive effect of these drugs. Monitor blood pressure. (7) ACE Inhibitors and ARBs : Concomitant use with Naproxen Tablets 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 Naproxen Tablets can increase serum concentration and prolong half-life of digoxin. Monitor serum digoxin levels. (7)

Naproxen sodium tablets treat rheumatoid arthritis, osteoarthritis, ankylosing spondylitis, and juvenile arthritis. They also relieve tendonitis, bursitis, acute gout, pain, and primary dysmenorrhea. "Use the lowest effective dosage for the shortest duration consistent with individual patient treatment goals."

2 DOSAGE AND ADMINISTRATION Use the lowest effective dosage for shortest duration consistent with individual patient treatment goals. (2.1) Rheumatoid Arthritis, Osteoarthritis, and Ankylosing Spondylitis Naproxen Tablets 250 mg 375 mg 500 mg twice daily twice daily twice daily The dose may be adjusted up or down depending on the clinical response of the patient. In patients who tolerate lower doses well, the dose may be increased to naproxen 1500 mg/day for up to 6 months. Polyarticular Juvenile Idiopathic Arthritis Naproxen tablets may not allow for the flexible dose titration needed in pediatric patients with polyarticular juvenile idiopathic arthritis. A liquid formulation may be more appropriate. Recommended total daily dose of naproxen is approximately 10 mg/kg given in 2 divided doses. Dosing with naproxen tablets is not appropriate for children weighing less than 50 kilograms. Acute Gout Recommended starting dose 750 mg of Naproxen Tablets followed by 250 mg every 8 hours until the attack has subsided. 2.1 General Dosing Instructions Carefully consider the potential benefits and risks of Naproxen Tablets and other treatment options before deciding to use Naproxen Tablets. Use the lowest effective dose for the shortest duration consistent with individual patient treatment goals [see Warnings and Precautions (5) ]. After observing the response to initial therapy with Naproxen Tablets, the dose and frequency should be adjusted to suit an individual patient’s needs. Naproxen-containing products such as Naproxen Tablets and other naproxen products should not be used concomitantly since they all circulate in the plasma as the naproxen anion. 2.2 Rheumatoid Arthritis, Osteoarthritis and Ankylosing Spondylitis The recommended dosages of Naproxen Tablets are shown in Table 1. Table 1: Recommended dosages for Naproxen Tablets Naproxen Tablets 250 mg 375 mg 500 mg twice daily twice daily twice daily During long-term administration, the dose of naproxen may be adjusted up or down depending on the clinical response of the patient. A lower daily dose may suffice for long-term administration. The morning and evening doses do not have to be equal in size and administration of the drug more frequently than twice daily does not generally make a difference in response. In patients who tolerate lower doses well, the dose may be increased to naproxen 1500 mg per day for limited periods of up to 6 months when a higher level of anti-inflammatory/analgesic activity is required. When treating such patients with naproxen 1500 mg per day, the physician should observe sufficient increased clinical benefits to offset the potential increased risk. 2.3 Polyarticular Juvenile Idiopathic Arthritis Naproxen solid-oral dosage forms may not allow for the flexible dose titration needed in pediatric patients with polyarticular juvenile idiopathic arthritis. A liquid formulation may be more appropriate for weight-based dosing and due to the need for dose flexibility in children. In pediatric patients, doses of 5 mg/kg/day produced plasma levels of naproxen similar to those seen in adults taking 500 mg of naproxen [see Clinical Pharmacology (12) ]. The recommended total daily dose of naproxen is approximately 10 mg/kg given in 2 divided doses. Dosing with naproxen tablets is not appropriate for children weighing less than 50 kilograms. 2.4 Management of Pain, Primary Dysmenorrhea, and Acute Tendonitis and Bursitis The recommended starting dose of Naproxen tablets is 500 mg followed by 250 mg (one half of a 500 mg naproxen tablet) every 6-8 hours as required. The total daily dose should not exceed 1,250 mg of naproxen. 2.5 Acute Gout The recommended starting dose is 750 mg of Naproxen tablets followed by 250 mg every 8 hours until the attack has subsided. 2.6 Non-Interchangeability with Other Formulations of Naproxen Different dose strengths and formulations (e.g., tablets, suspension) of naproxen are not interchangeable. This difference should be taken into consideration when changing strengths or formulations.