Drug Interactions between dexamethasone / moxifloxacin and verteporfin

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: Concomitant use of verteporfin with other known photosensitizing agents may increase the risk of photosensitivity reactions. Examples of medicinal products with known phototoxic or photoallergic potential include fluoroquinolones, phenothiazines, retinoids, sulfonamides, sulfonylureas, tetracyclines, thiazide diuretics, griseofulvin, and hypericin extracts (e.g., St John's Wort).

MANAGEMENT: Caution is advised and pharmacologic response to photodynamic therapy should be carefully monitored if concomitant use of other photosensitizing agents cannot be avoided. Patients will become photosensitive, so they should avoid exposure of unprotected skin, eyes, or other body organs to direct sunlight, bright indoor lights (e.g., tanning salons, bright halogen lights, high power lighting in a surgery operating room), and even prolonged exposure from light-emitting medical devices (e.g., pulse oximeter) for 5 days following the infusion of verteporfin. Patients should be counseled to protect their skin and eyes by wearing protective clothing and dark sunglasses if they must go outdoors in daylight during this time, as UV sunscreens are not effective in protecting against photosensitivity reactions. If emergency surgery is necessary within 48 hours of the verteporfin infusion, as much of the patient's internal tissue as possible should be protected from intense light. Patients should be encouraged to expose their skin to ambient indoor light as it is safe and will help eliminate verteporfin through the skin by a process called "photobleaching."