Plasma concentrations of methylergometrine after intravenous and intramuscular administration.

The concentrations of methylergometrine (M) in the plasma were determined by a new radioimmunoassay after a single intravenous and intramuscular administration of two brands. Methergin (Sandoz Pharmaceuticals, Inc, East Hanover, NJ, USA) and Myomergin (Leiras Pharmaceuticals, Turku, Finland). No significant differences between the two brands were found. After the intravenous injection, M distributed quickly from the plasma to the tissues, and according to the elimination phase half-life M has no cumulative properties. After the intramuscular injection, M was absorbed quickly with peak plasma concentrations at one-half hour.