A clamp adapter for a catheter has a clamp body (10) that receives an elastomeric clamp bushing. In order to fix a catheter inserted into the clamp bushing, the clamp bushing is axially compressed by a clamp lid (24). For this purpose, the clamp lid (24) is moved axially on the clamp body (10) with a clamp lever (30) by means of a slotted guide (42, 44).