In this paper we identify the mechanisms in the IEEE 802.11 standard which limit medium reuse by not allowing concurrent transmissions even when they are actually possible. To improve medium reuse we propose an interference management protocol, PCONAV, which cognitively enables and disables the virtual (NAV) and physical carrier sensing (CCA) according to the interference environment. We combine this mechanisms with address filtering and capture and demonstrate improved medium reuse. The proposed cognitive mechanisms are further enhanced with a tuning mechanism that adapts the carrier sensing threshold (CST) at each node. Simulations are used to show the improved performance obtained with each of the proposed mechanisms.