A method and apparatus for introducing a medicinal dose directly into a mammalian patient's cerebrospinal fluid. One embodiment of the present invention comprises implanting a first and second device in a mammalian patient to administer the medicinal dose. The first device comprises a ventricular catheter, a reservoir with a built-in one-way valve, and a drug port with pump, wherein the three components are in fluid communication. The second device comprises a drug port-catheter system in fluid contact with lumbar sub-arachnoid space.