Drug Interactions between Extra Strength Bayer and monomethyl fumarate

MONITOR: The use of fumaric acid esters in combination with medications that can cause nephrotoxicity, including aspirin at anti-inflammatory dosages, may increase the potential for adverse renal reactions. In clinical trials in patients with multiple sclerosis treated with dimethyl fumarate, a fumaric acid ester that is converted to the active metabolite monomethyl fumarate (MMF), adverse events of proteinuria were reported at slightly higher frequencies than in patients receiving placebo. The clinical significance of these observations is unknown. Cases of Fanconi syndrome have been reported for a medicinal product containing dimethyl fumarate in combination with other fumaric acid esters. Renal toxicity, including tubular changes and/or interstitial fibrosis, has been observed in animal studies with dimethyl fumarate and diroximel fumarate. In healthy volunteers, administration of 325 mg non-enteric coated aspirin approximately 30 minutes prior to dimethyl fumarate for up to 4 weeks did not alter the pharmacokinetics of dimethyl fumarate or MMF.

MANAGEMENT: Administration of non-enteric coated aspirin (up to 325 mg) prior to fumaric acid esters such as monomethyl fumarate or its prodrugs, dimethyl fumarate or diroximel fumarate, may help reduce the incidence and/or severity of flushing. However, as there are no long-term studies evaluating the continuous use of aspirin in this situation for longer than 4 weeks, caution is advised. Assessment of renal function (e.g., serum creatinine, blood urea nitrogen, urinalysis) is recommended prior to initiating treatment with fumaric acid esters and as clinically indicated during treatment.