A piston-type internal-combustion engine having deactivatable, mechanically actuated cylinder valves that are respectively actuated by at least one camshaft via a roller drag lever (5) comprising two partial levers (5.1, 5.2) that are hinged to one another via an articulated shaft (6), on which the roller (7) associated with a cam (8) of the camshaft is rotatably seated. A locking mechanism (13) is provided to selectively couple or decouple the two partial levers (5.1, 5.2) to activate or deactivate the force transmission between the camshaft and the cylinder valve. The free end 5.11 of one partial lever (5.1) is supported on the cylinder valve (2), and the free end 5.21 of the other partial lever (5.2) is supported on the engine block (11).