Levonordefrin

Levonordefrin is the (-)-enantiomer of nordefrin, a synthetic derivative of norepinephrine , that acts as a vasoconstrictor. Levonordefrin (1-5 µg/kg) rapidly increases blood pressure and heart rate in anesthetized dogs and has a more potent effect on blood pressure than the dextronordefrin enantiomer. It also inhibits carbamylcholine-induced uterine contractions in isolated rat uterine strips (EC50 = 0.0032 µg/ml). Levonordefrin (0.514 and 1.542 mg/kg), in combination with mepivacaine and administered via intraoral infiltration, increases systolic arterial blood pressure in anesthetized dogs, however, the effect is not dose-dependent and the increase is not greater than 5.33%. Formulations containing levonordefrin have been used in combination with local anesthetics in dentistry to prolong anesthetic effects.