Myopathy after long-term administration of other non-depolarizing neuromuscular blocking agents in the ICU alone or in combination with corticosteroid therapy has been reported. Therefore, for patients receiving both neuromuscular blocking agents and corticosteroids, the period of use of the neuromuscular blocking agent should be limited as much as possible and only used in the setting where in the opinion of the prescribing agent, the specific advantages outweigh the risk.ZEMURON has not been studied in malignant hyperthermia-susceptible patients. Because ZEMURON is always used with other agents, and the occurrence of malignant hyperthermia during anesthesia is possible even in the absence of known triggering agents, clinicians should be familiar with early signs, confirmatory diagnosis and treatment of malignant hyperthermia prior to the start of any anesthetic. Conditions associated with an increased circulatory delayed time, e.g., cardiovascular disease or advanced age, may be associated with a delay in onset time. The overall analysis of ECG data in pediatric patients indicates that the concomitant use of ZEMURON with general anesthetic agents can prolong the QTc interval. Non-depolarizing neuromuscular blocking agents have been found to exhibit profound neuromuscular blocking effects in cachectic or debilitated patients, patients with neuromuscular diseases and patients with carcinomatosis. Certain inhalation anesthetics, particularly enflurane and isoflurane, antibiotics, magnesium salts, lithium, local anesthetics, procainamide and quinidine, have been shown to increase the duration of neuromuscular block and decrease infusion requirements of neuromuscular blocking agents. In these or other patients in whom potentiation of neuromuscular block or difficulty with reversal may be anticipated, a decrease from the recommended initial dose of ZEMURON should be considered. Resistance to non-depolarizing agents, consistent with up-regulation of skeletal muscle acetylcholine receptors, is associated with burns, disuse atrophy, denervation, and direct muscle trauma. Receptor up-regulation may also contribute to the resistance to non-depolarizing muscle relaxants, which sometimes develops in patients with cerebral palsy, patients chronically receiving anticonvulsant agents, such as carbamazepine or phenytoin, or with chronic exposure to non-depolarizing agents. When ZEMURON (rocuronium bromide) is administered to these patients, shorter durations of neuromuscular block may occur, and infusion rates may be higher due to the development of resistance to non-depolarizing muscular relaxants.