Drug Interactions between aliskiren and lomitapide

ADJUST DOSING INTERVAL: Administration of lomitapide with food may increase the risk of common gastrointestinal adverse reactions such as diarrhea, nausea, vomiting, dyspepsia, abdominal pain or discomfort, abdominal distension, constipation, and flatulence. Absorption of concomitant oral medications may be affected in patients who develop diarrhea or vomiting.

GENERALLY AVOID: Grapefruit juice may significantly increase the plasma concentrations of lomitapide. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruit. Weak CYP450 3A4 inhibitors can increase lomitapide exposure (AUC) by approximately 2-fold according to the product labeling. Ketoconazole, a potent CYP450 3A4 inhibitor, has been shown to increase lomitapide AUC by 27-fold .

GENERALLY AVOID: Coadministration with alcohol may increase the risk of hepatotoxicity associated with the use of lomitapide. In a premarketing clinical trial, 34% (10/29) of patients treated with lomitapide had at least one elevation in alanine aminotransferase (ALT) or aspartate aminotransferase (AST) 3 times the upper limit of normal (ULN) or greater, and 14% (4/29) had at least one elevation in ALT or AST 5 times ULN or greater. There were no concomitant clinically meaningful elevations of total bilirubin, international normalized ratio (INR), or alkaline phosphatase. Lomitapide also increases hepatic fat, with or without concomitant increases in transaminases. In the same study, the median absolute increase in hepatic fat was 6% after both 26 and 78 weeks of treatment, from 1% at baseline, measured by magnetic resonance spectroscopy. Hepatic steatosis associated with lomitapide may be a risk factor for progressive liver disease, including steatohepatitis and cirrhosis. Clinical data suggest that hepatic fat accumulation is reversible after stopping treatment with lomitapide, although the long-term consequences are unknown.

MANAGEMENT: Lomitapide should be taken once daily with a glass of water, without food, at least 2 hours after the evening meal. Strict adherence to a low-fat diet (<20% of total calories from fat) and gradual dosage titration may also help to reduce gastrointestinal intolerance. Patients should avoid consumption of grapefruit, grapefruit juice, and any supplement containing grapefruit extract during treatment with lomitapide. Since alcohol may increase levels of hepatic fat and induce or exacerbate liver injury, the manufacturer recommends that patients taking lomitapide not consume more than one alcoholic drink per day.

GENERALLY AVOID: Coadministration with orange, apple, or grapefruit juice may significantly decrease the oral bioavailability and renin-inhibiting effect of aliskiren. The exact mechanism of interaction is unknown, but may include inhibition of OATP2B1-mediated influx of aliskiren in the small intestine, formation of insoluble complexes between fruit juice constituents and aliskiren, and/or increased ionization of aliskiren due to reduced intestinal pH. In 12 healthy volunteers, 200 mL of either orange juice or apple juice administered three times daily for 5 days in combination with a single 150 mg oral dose of aliskiren on day 3 reduced the mean aliskiren peak plasma concentration (Cmax) and systemic exposure (AUC) by approximately 80% and 60%, respectively, compared to water. Plasma renin activity was 87% and 67% higher at 24 hours postdose when aliskiren was administered with orange juice and apple juice, respectively, compared to water. No significant differences were observed in the blood pressure or heart rate between treatments. However, this may be due to the delayed onset of aliskiren's blood pressure-lowering effect, which would not be apparent following a single dose. A similar pharmacokinetic interaction has been reported with grapefruit juice. In 11 healthy volunteers, 200 mL of normal strength grapefruit juice administered three times daily for 5 days in combination with a single 150 mg oral dose of aliskiren on day 3 reduced the mean aliskiren Cmax and AUC by 81% and 61%, respectively, but there was no change in plasma renin activity compared to water. A high degree of interpatient variability was observed with all three interactions.

MONITOR: High-fat meals can substantially reduce the gastrointestinal absorption of aliskiren. According to the product labeling, administration of aliskiren with a high-fat meal decreased the mean peak plasma concentration (Cmax) and systemic exposure (AUC) by 85% and 71%, respectively. In clinical trials, however, aliskiren was administered without a fixed requirement in relation to meals.

MANAGEMENT: To ensure steady systemic drug levels and therapeutic effects, patients should establish a routine pattern for administration of aliskiren with regard to meals. Coadministration with orange, apple, or grapefruit juice should be avoided, especially if these juices are to be consumed on a regular basis or shortly before or after aliskiren dosing.