Drug Interactions between belumosudil and naltrexone

ADJUST DOSING INTERVAL: Administration with food increases the oral bioavailability of belumosudil. The mechanism has not been described. Administration of belumosudil (200 mg single oral dose) in healthy subjects, with a fatty and calorie-rich meal (approximately half of the calories were contained in the fat) increased the mean belumosudil peak plasma concentration (Cmax) and area under the concentration-time curve (AUC) by 120% and 100%, respectively, compared to administration under fasting conditions. The time to reach peak concentration (Tmax) was delayed by 30 minutes. Administration of oral belumosudil 200 mg once daily with food in patients with chronic graft-versus-host disease (chronic GVHD) lead to steady-state concentrations of the drug with an accumulation ration of 1.4.

MANAGEMENT: To ensure maximal oral absorption, belumosudil should be administered with a meal, every day at the same time.

GENERALLY AVOID: Coadministration of naltrexone with other agents known to induce hepatotoxicity may potentiate the risk of liver injury. Naltrexone, especially in larger than recommended doses (more than 50 mg/day), has been associated with hepatocellular injury, hepatitis, and elevations in liver transaminases and bilirubin. Other potential causative or contributory etiologies identified include preexisting alcoholic liver disease, hepatitis B and/or C infection, and concomitant usage of other hepatotoxic drugs.

MANAGEMENT: The use of naltrexone with other potentially hepatotoxic agents should be avoided whenever possible (e.g., acetaminophen; alcohol; androgens and anabolic steroids; antituberculous agents; azole antifungal agents; ACE inhibitors; cyclosporine (high dosages); disulfiram; endothelin receptor antagonists; interferons; ketolide and macrolide antibiotics; kinase inhibitors; minocycline; nonsteroidal anti-inflammatory agents; nucleoside reverse transcriptase inhibitors; proteasome inhibitors; retinoids; sulfonamides; tamoxifen; thiazolidinediones; tolvaptan; vincristine; zileuton; anticonvulsants such as carbamazepine, hydantoins, felbamate, and valproic acid; lipid-lowering medications such as fenofibrate, lomitapide, mipomersen, niacin, and statins; herbals and nutritional supplements such as black cohosh, chaparral, comfrey, DHEA, kava, pennyroyal oil, and red yeast rice). Patients should be advised to seek medical attention if they experience potential signs and symptoms of hepatotoxicity such as fever, rash, itching, anorexia, nausea, vomiting, fatigue, malaise, right upper quadrant pain, dark urine, pale stools, and jaundice. Periodic monitoring of hepatic function is advisable.