Uses for Bretylium
Bretylium Tosylate Injection, USP is indicated in the prophylaxis and therapy of ventricular fibrillation.
Bretylium Tosylate Injection, USP is also indicated in the treatment of life-threatening ventricular arrhythmias, such as ventricular tachycardia that have failed to respond to adequate doses of a first-line antiarrhythmic agent, such as lidocaine.
Use of Bretylium Tosylate Injection, USP should be limited to intensive care units, coronary care units or other facilities where equipment and personnel for constant monitoring of cardiac arrhythmias and blood pressure are available.
Following injection of bretylium tosylate there may be a delay of 20 minutes to 2 hours in the onset of antiarrhythmic action, although it appears to act within minutes in ventricular fibrillation. The delay in effect appears to be longer after intramuscular than after intravenous injection.
Dosage for Bretylium
Bretylium Tosylate Injection, USP is to be used clinically only for treatment of life-threatening ventricular arrhythmias under constant electrocardiographic monitoring. The clinical use of bretylium tosylate is for short-term use only. Patients should either be kept supine during the course of bretylium tosylate therapy or be closely observed for postural hypotension. The optimal dose schedule for parenteral administration of bretylium tosylate has not been determined. There is comparatively little experience with dosages greater than 40 mg/kg/day, although such doses have been used without apparent adverse effects. The following schedule is suggested.
For Immediately Life-threatening Ventricular Arrhythmias Such As Ventricular Fibrillation Or Hemodynamically Unstable Ventricular Tachycardia
Administer undiluted Bretylium Tosylate Injection, USP at a dosage of 5 mg/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 10 mg/kg and repeated as necessary.
For continuous suppression, dilute contents of one Bretylium Tosylate Injection, USP 10 mL container (500 mg) to a minimum of 50 mL with 5% Dextrose Injection, USP or Sodium Chloride Injection, USP and administer the diluted solution as a constant infusion of 1 to 2 mg bretylium tosylate per minute. An alternative maintenance schedule is to infuse the diluted solution at a dosage of 5 to 10 mg bretylium 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.
Other Ventricular Arrhythmias
Intravenous Use
Bretylium Tosylate Injection,USP must be diluted as described above before intravenous use.
Administer the diluted solution at a dosage of 5 to 10 mg bretylium 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.
For maintenance therapy, the same dosage may be administered every 6 hours, or a constant infusion of 1 to 2 mg bretylium tosylate per minute may be given.
For Intramuscular Injection
Do not dilute Bretylium Tosylate Injection, USP prior to intramuscular injection. Inject 5 to 10 mg bretylium 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. No more than 5 mL should be injected intramuscularly in one site.
As soon as possible, and when indicated, patients should be changed to an oral antiarrhythmic agent for maintenance therapy.
Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit. Slight discoloration does not alter potency.
Do not administer unless solution is clear and container is undamaged. Discard unused portion.
HOW SUPPLIED
Bretylium Tosylate Injection, USP is supplied in 10 mL single-dose glass vials (NDC 62559-870-11).
Store at 20° to 25°C (68° to 77°F); [see USP Controlled Room Temperature].
Manufactured by: Pharmaceutics International, Inc. (Pii), Cockeysville, MD 21030. Distributed by: ANI Pharmaceuticals, Inc., Baudette, MN 56623. Revised: Oct 2019