Drug Interactions between moxifloxacin / triamcinolone and perflutren

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.

GENERALLY AVOID: Perflutren lipid microsphere suspension (Definity)has been reported to cause 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 221 study subjects who received ECG monitoring at various time points from 1 to 72 hours following administration of perflutren lipid microsphere bolus doses of up to 10 microL/kg, QTc prolongations of >30 msec were noted in 64 (29%) subjects. Forty-six out of these 64 subjects were further evaluated, and 18 (39%) were found to have associated cardiac rhythm changes. The effects of concomitant drugs were not studied. 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: Concomitant use of perflutren lipid microsphere suspension with other agents that can prolong the QT interval should be avoided in some cases. Please refer to the prescribing information for these drugs for more information. No data are available regarding the effect of perflutren protein-type A microsphere suspension (Optison) on the QT interval of the electrocardiogram.