A pressure valve including a body including at least one admission opening and at least one discharge opening, a slide valve sliding in the body, the slide valve defining a chamber, with the body, and including a head arranged facing a seat of the admission opening, a spring pressing the head of the slide valve against the seat, a lip for applying the head to the seat. The head includes at least one hole bringing the chamber into communication with the discharge opening, each hole being arranged facing the seat and downstream from the lip in relation to the admission opening in order to reduce the pressure in the chamber by a Venturi effect when the slide valve is open.