An implantable device for venous or peritoneal access including a housing including a void having distal a proximal openings an insert for insertion through the proximal opening comprising a venous or peritoneal catheter a valve element mounted in a cylindrical recess of the insert an extracorporeal coupling member of which a terminal portion can be inserted into a proximal recess of the valve element one or two conduits extending from the catheter to the proximal end of the coupling member via the valve element and the insert for providing fluid communication, which can be interrupted by rotating the coupling member. The coupling member can be extracted from the recess only in a state of interrupted communication.