Drug Interactions between dexamethasone / moxifloxacin and suvorexant

MONITOR CLOSELY: Concomitant administration of corticosteroids may potentiate the risk of tendinitis and tendon rupture associated with fluoroquinolone treatment. The mechanism is unknown. Tendinitis and tendon rupture have most frequently involved the Achilles tendon, although cases involving the rotator cuff (the shoulder), the hand, the biceps, and the thumb have also been reported. Some have required surgical repair or resulted in prolonged disability. Tendon rupture can occur during or up to several months after completion of fluoroquinolone therapy.

MANAGEMENT: Caution is recommended if fluoroquinolones are prescribed in combination with corticosteroids, particularly in patients with other concomitant risk factors (e.g., age over 60 years; recipient of kidney, heart, and/or lung transplant). Patients should be advised to stop taking the fluoroquinolone, avoid exercise and use of the affected area, and promptly contact their physician if they experience pain, swelling, or inflammation of a tendon. In general, fluoroquinolones should only be used to treat conditions that are proven or strongly suspected to be caused by bacteria and only if the benefits outweigh the risks.

MONITOR: Coadministration with inducers of CYP450 3A4 may decrease the plasma concentrations of suvorexant, which is primarily metabolized by the isoenzyme. According to the product labeling, suvorexant peak plasma concentration (Cmax) and systemic exposure (AUC) decreased by approximately 70% and 90%, respectively, when coadministered with the potent CYP450 3A4 inducer rifampin (600 mg). No data are available for use with other, less potent inducers.

MANAGEMENT: The potential for diminished therapeutic effects of suvorexant should be considered when prescribed with inducers of CYP450 3A4. Pharmacologic effects of suvorexant should be monitored more closely whenever an inducer is added to or withdrawn from therapy, and the suvorexant dosage adjusted as necessary.