fluphenazine

1.The antipsychotic drug fluphenazine has a prolonged period of action when it is given by intramuscular injection, but not when it is given by intravenous injection.Suggest why this is the case.

精神抑制药氟奋，用肌肉注射的话会有一段延迟的反应期，但是用静脉注射却没有，说明为什么会出现这种情况。