A method for treating or preventing a disorder or a condition by double inhibition of serotonin (5-HT) and noradrenaline (NA) reuptake in a subject in need thereof, while limiting the risks of cardiovascular disturbances and/or organ and/or tissue toxicity, comprising the step of administering to said subject a mixture of enantiomers of milnacipran enriched in the (1S,2R) enantiomer of milnacipran and/or of at least one of its metabolites, as well as their pharmaceutically-acceptable salts.