BRETYLIUM (bretylium tosylate injection ) TOSYLATE INJECTION is to be used clinically only for treatment of life-threatening ventricular arrhythmias under constant electrocardiographic monitoring. The clinical use of BRETYLIUM (bretylium tosylate injection ) TOSYLATE INJECTION is for short-term use only. Patients should either be kept supine during the course of bretylium (bretylium tosylate injection ) therapy or be closely observed for postural hypotension. The optimal dose schedule for parenteral administration of the drug has not been determined. There is comparatively little experience with dosages greater than 40mg/kg/day, although such doses have been used without apparent adverse effects. The following schedules are suggested: A. For immediately Life-threatening Ventricular Arrhythmias such as Ventricular Fibrillation or Hemodynamically Unstable Ventricular Tachycardia: Administer undiluted BRETYLIUM (bretylium tosylate injection ) TOSYLATE INJECTION at a dosage of 5mg/kg of body weight by rapid intravenous injection. Other usual cardiopulmonary resuscitative procedures, including electrical cardioversion, should be employed prior to and following the injection in accordance with good medical practice. If ventricular fibrillation persists, the dosage may be increased to 10mg/kg and repeated as necessary. For continuous suppression, dilute Bretylium (bretylium tosylate injection ) Tosylate Injection with Dextrose Injection, USP or Sodium Chloride Injection, USP using the table below and administer the diluted solution as a constant infusion of 1 to 2mg Bretylium (bretylium tosylate injection ) Tosylate Injection per minute, (see Table below). When administering Bretylium (bretylium tosylate injection ) Tosylate Injection (or any potent medication) by continuous intravenous infusion, it is advisable to use a precision volume control device. An alternative maintenance schedule is to infuse the diluted solution at a dosage of 5 to 10mg Bretylium (bretylium tosylate injection ) Tosylate per kg body weight, over a period greater than 8 minutes, every 6 hours. More rapid infusion may cause nausea and vomiting, and in patients older than 65 years, may increase the risk of developing orthostatic hypotension. B. Other ventricular arrhythmias: 1) Intravenous Use: Bretylium (bretylium tosylate injection ) tosylate injection must be diluted as described above before intravenous use. Administer the diluted solution at a dosage of 5 to 10mg bretylium (bretylium tosylate injection ) tosylate per kg of body weight by intravenous infusion over a period greater than 8 minutes. More rapid infusion may cause nausea and vomiting, and in patients older than 65 years, may increase the risk of developing orthostatic hypotension. Subsequent doses may be given at 1 to 2 hour intervals if the arrhythmia persists. 2) For Intramuscular Injection: DO NOT DILUTE BRETYLIUM (bretylium tosylate injection ) TOSYLATE INJECTION PRIOR TO INTRAMUSCULAR INJECTION. Inject 5 to 10mg bretylium (bretylium tosylate injection ) tosylate per kg of body weight. Subsequent doses may be given at 1 to 2 hour intervals if the arrhythmia persists. Thereafter, maintain the same dosage every 6 to 8 hours. Intramuscular injection should not be made directly into or near a major nerve, and the site of injection should be varied on repeated injection. Not more than 5mL should be injected intramuscularly in one site. (See PRECAUTONS) As soon as possible, and when indicated, patients should be changed to an oral antiarrhythmic agent for maintenance therapy.

bretylium at 1-100 uM prolonged the action potentials of the Wistar Kyoto normotensive rat left ventricular strip.