Drug Interactions between moxifloxacin / triamcinolone and succinylcholine

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: The neuromuscular blocking effect of succinylcholine may be potentiated by chronic administration of estrogens or high-dose corticosteroids. Available data suggest that steroids may reduce plasma cholinesterase activity, resulting in decreased metabolic clearance of succinylcholine. There have been isolated case reports of patients treated with estrogen-containing products such as estradiol and diethylstilbestrol who experienced prolonged apnea or muscle paralysis following succinylcholine administration. Laboratory testing demonstrated reduced serum pseudocholinesterase activity in these patients. One study conducted in 33 women of childbearing age reported significantly reduced serum cholinesterase levels after one month of treatment with various oral contraceptives, with no further reductions after three months. Another 33 women in the same study who had been taking oral contraceptives for at least one year exhibited similarly reduced levels of serum cholinesterase.

MANAGEMENT: Patients receiving chronic therapy with estrogens or corticosteroids should be monitored for increased or prolonged neuromuscular blockade when succinylcholine is administered. A lower initial dosage of succinylcholine may be required.