Drug Interactions between panobinostat and Tabloid

GENERALLY AVOID: Grapefruit juice may increase the plasma concentrations of panobinostat. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruit. Increased exposure to panobinostat may increase the risk of adverse effects such as nausea, vomiting, diarrhea, anorexia, peripheral edema, cardiotoxicity, ECG abnormalities, electrolyte disturbances, bleeding complications, hepatotoxicity, and myelosuppression.

Food may delay the rate of absorption of panobinostat, but does not significantly affect the overall extent of absorption. When a single oral dose of panobinostat was administered to 36 patients with advanced cancer 30 minutes after a high-fat meal, panobinostat peak plasma concentration (Cmax) and systemic exposure (AUC) were approximately 44% and 16% lower, respectively, compared to administration under fasting conditions. The median time to maximum concentration (Tmax) was prolonged by 2.5 hours.

MANAGEMENT: Patients should avoid consumption of grapefruit or grapefruit juice during treatment with panobinostat. The manufacturer also recommends avoiding star fruit, Seville oranges, pomegranate, and pomegranate juice. Panobinostat may be administered with or without food.

MONITOR: The concomitant or sequential use of other agents known to induce hepatotoxicity may potentiate the risk of liver injury associated with thioguanine. A high risk of liver toxicity characterized by vascular endothelial damage has been reported with long-term continuous use of thioguanine, particularly in children receiving the drug as part of maintenance therapy for acute lymphoblastic leukemia and in other conditions associated with continuous use. Liver toxicity usually presents as the clinical syndrome of hepatic veno-occlusive disease (hyperbilirubinemia, tender hepatomegaly, weight gain due to fluid retention, and ascites) or with signs of portal hypertension (splenomegaly, thrombocytopenia, and esophageal varices). Histopathological features include hepatoportal sclerosis, nodular regenerative hyperplasia, peliosis hepatitis, and periportal fibrosis.

MANAGEMENT: The risk of hepatic injury should be considered when thioguanine is used with other potentially hepatotoxic agents (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. Baseline and regular monitoring of hepatic function is recommended. Thioguanine therapy should be discontinued if there is evidence of toxic hepatitis or biliary stasis, as reversal of signs and symptoms of liver toxicity have been reported upon withdrawal. Early indications of liver toxicity are signs associated with portal hypertension such as thrombocytopenia out of proportion with neutropenia and splenomegaly. Elevations of liver enzymes have also been reported, but do not always occur.