7 DRUG INTERACTIONS
See Table 1 for clinically significant drug interactions with diclofenac and misoprostol.
|Drugs That Interfere with Hemostasis|
|Intervention:||Monitor patients with concomitant use of ARTHROTEC 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)].|
|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 ARTHROTEC and analgesic doses of aspirin is not generally recommended because of the increased risk of bleeding [see Warnings and Precautions (5.11)].|
ARTHROTEC is not a substitute for low dose aspirin for cardiovascular protection.
|ACE Inhibitors, Angiotensin Receptor Blockers, and Beta-Blockers|
|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 ARTHROTEC 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)].|
|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 ARTHROTEC and digoxin, monitor serum digoxin levels.|
|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 ARTHROTEC and lithium, monitor patients for signs of lithium toxicity.|
|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 ARTHROTEC and methotrexate, monitor patients for methotrexate toxicity.|
|Clinical Impact:||Concomitant use of diclofenac and cyclosporine may increase cyclosporine's nephrotoxicity.|
|Intervention:||During concomitant use of ARTHROTEC 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)].|
|Intervention:||The concomitant use of ARTHROTEC with other NSAIDs or salicylates is not recommended.|
|Clinical Impact:||Concomitant use of diclofenac and pemetrexed may increase the risk of pemetrexed-associated myelosuppression, renal, and GI toxicity (see the pemetrexed prescribing information).|
|Intervention:||During concomitant use of ARTHROTEC and pemetrexed, in patients with renal impairment whose creatinine clearance ranges from 45 to 79 mL/min, monitor for myelosuppression, renal and GI toxicity.|
Avoid ARTHROTEC for a period of two days before, the day of, and two days following administration of pemetrexed.
|Clinical Impact:||Antacids reduce the bioavailability of misoprostol acid. Antacids may also delay absorption of diclofenac. Magnesium-containing antacids exacerbate misoprostol-associated diarrhea.|
|Intervention:||Concomitant use of ARTHROTEC and magnesium-containing antacids is not recommended.|
|Clinical Impact:||Concomitant use of corticosteroids with diclofenac may increase the risk of GI ulceration or bleeding.|
|Intervention||Monitor patients with concomitant use of ARTHROTEC with corticosteroids for signs of bleeding [see Warnings and Precautions (5.2)].|
|CYP2C9 Inhibitors or Inducers|
|Clinical Impact:||Diclofenac is metabolized by cytochrome P450 enzymes, predominantly by CYP2C9. Co-administration of diclofenac with CYP2C9 inhibitors (e.g., voriconzaole) may enhance the exposure and toxicity of diclofenac [see Clinical Pharmacology (12.3)] whereas co-administration with CYP2C9 inducers (e.g., rifampin) may lead to compromised efficacy of diclofenac.|
|Intervention:||CYP 2C9 inhibitors: When concomitant use of CYP2C9 inhibitors is necessary, the total daily dose of diclofenac should not exceed the lowest recommended dose of ARTHROTEC 50 twice daily [see Dosage and Administration (2)].|
CYP2C9 inducers: A dosage adjustment may be warranted when ARTHROTEC is administered with CYP2C9 inducers. Administer the separate products of misoprostol and diclofenac if a higher dose of diclofenac is deemed necessary.