 The major metabolites of gestonorone caproate have been reported to be isomers of 19-norpregnanetriol and 19-norpregnanediol-20-one.These metabolites indicate that gestonorone caproate is metabolized mainly by reduction at the C3, C5, and C20 positions.Following an intramuscular injection of 300 mg gestonorone caproate, only a slight increase in urinary pregnanetriol excretion has been observed.