Maintenance doses of 0.03 mg/kg intravenous sustain neuromuscular blockade for about 20 minutes. Maintenance dosing is generally required 40 to 50 minutes after an initial dose of 0.15 mg/kg intravenously or 50 to 60 minutes after an initial dose of 0.2 mg/kg intravenously. For shorter or longer durations of action, smaller or larger maintenance doses may be administered.