Drug Interaction Report

MONITOR CLOSELY: Bedaquiline can cause dose-related prolongation of the QT interval. Theoretically, coadministration with other agents that can prolong the QT interval may result in additive effects and increased risk of ventricular arrhythmias including torsade de pointes and sudden death. In one clinical study, the mean increase in Fridericia-corrected QT interval (QTcF) was 9.9 msec in subjects receiving bedaquiline and 3.5 msec in subjects receiving placebo after the first week of treatment. The largest mean increase in QTc during the 24 weeks of bedaquiline treatment was 15.7 msec, compared to 6.2 msec for placebo at week 18. QT increases from baseline in the bedaquiline group persisted even after treatment was stopped. In another study where patients with no treatment options received other QT-prolonging drugs used to treat tuberculosis, concurrent use of bedaquiline resulted in additive QT prolongation proportional to the number of QT-prolonging drugs in the treatment regimen. Patients receiving bedaquiline alone with no other QT-prolonging drugs developed a mean QTcF increase over baseline of 23.7 msec. There was no QT segment duration in excess of 480 msec in this group, whereas patients receiving at least two other QT-prolonging drugs developed a mean QTcF prolongation of 30.7 msec over baseline, resulting in QTcF segment durations in excess of 500 msec in one patient. Mean increases in QTc were also larger in the 17 subjects who were using clofazimine with bedaquiline than in those who were not using clofazimine with bedaquiline (31.9 msec versus 12.3 msec at week 24). There were no documented cases of torsade de pointes in the safety database. In general, the risk of an individual agent or a combination of agents causing ventricular arrhythmia in association with QT prolongation is largely unpredictable but may be increased by certain underlying risk factors such as congenital long QT syndrome, cardiac disease, and electrolyte disturbances (e.g., hypokalemia, hypomagnesemia). In addition, the extent of drug-induced QT prolongation is dependent on the particular drug(s) involved and dosage(s) of the drug(s).

MANAGEMENT: Caution is recommended if bedaquiline is used in combination with other drugs that can prolong the QT interval. ECG and serum electrolytes, including potassium, magnesium and calcium, should be monitored before starting bedaquiline therapy and periodically during treatment in accordance with the product labeling. Hypokalemia, hypomagnesemia, and hypocalcemia must be corrected prior to bedaquiline administration. All QT-prolonging drugs including bedaquiline should be interrupted in patients who develop clinically significant ventricular arrhythmia or a QTcF interval greater than 500 msec confirmed by repeat ECG. Patients should be advised to seek prompt medical attention if they experience symptoms that could indicate the occurrence of torsade de pointes such as dizziness, lightheadedness, fainting, palpitation, irregular heart rhythm, shortness of breath, or syncope.

GENERALLY AVOID: Coadministration with grapefruit or grapefruit juice may increase the plasma concentrations of rilpivirine. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall induced by certain compounds present in grapefruit. In 15 study subjects given rilpivirine (150 mg once daily) with the potent CYP450 3A4 inhibitor ketoconazole (400 mg once daily), mean rilpivirine peak plasma concentration (Cmax), systemic exposure (AUC) and trough plasma concentration (Cmin) were increased by 30%, 49% and 76%, respectively. In 16 study subjects given a single 500 mg dose of a less potent CYP450 3A4 inhibitor chlorzoxazone two hours after rilpivirine (150 mg once daily), mean rilpivirine Cmax, AUC, and Cmin were increased by 17%, 25%, and 18%, respectively. Because grapefruit juice inhibits primarily intestinal rather than hepatic CYP450 3A4, the magnitude of interaction is greatest for those drugs that undergo significant presystemic metabolism by CYP450 3A4 (i.e., drugs with low oral bioavailability). In general, the effect of grapefruit juice is concentration-, dose- and preparation-dependent, and can vary widely among brands. Certain preparations of grapefruit juice (e.g., high dose, double strength) have sometimes demonstrated potent inhibition of CYP450 3A4, while other preparations (e.g., low dose, single strength) have typically demonstrated moderate inhibition. Pharmacokinetic interactions involving grapefruit juice are also subject to a high degree of interpatient variability, thus the extent to which a given patient may be affected is difficult to predict.

ADJUST DOSING INTERVAL: The administration of rilpivirine in a fasting state may decrease its oral absorption. Under fasted conditions, the systemic exposure to rilpivirine was 40% lower compared to normal or high-fat caloric meals (533 to 928 Kcal). The systemic exposure was 50% lower when rilpivirine was taken with a protein-rich nutritional beverage.

MANAGEMENT: Coadministration of grapefruit or grapefruit juice with rilpivirine should preferably be avoided. For optimal absorption, it is recommended to take rilpivirine on a regular schedule with a meal.

ADJUST DOSING INTERVAL: Food enhances the oral bioavailability of bedaquiline. When administered with a standard meal containing approximately 22 grams of fat (558 total Kcal), the relative bioavailability of bedaquiline increased by approximately 2-fold compared to administration under fasted conditions.

GENERALLY AVOID: Coadministration with alcohol may increase the risk of hepatotoxicity associated with the use of bedaquiline. In clinical trials, hepatic adverse drug reactions developed in more bedaquiline-treated patients than in those who received other drugs used to treat tuberculosis. In patients receiving bedaquiline or placebo in combination with other drugs used to treat multidrug-resistant tuberculosis, reversible aminotransferase elevations of at least 3 times the upper limit of normal developed more frequently in the bedaquiline treatment group [10.8%] than in the placebo group [5.7%].

MANAGEMENT: To ensure maximal oral absorption, bedaquiline should be taken with food. Patients should avoid alcohol use during treatment.