The effect of the active medium prepulse parameters on the frequency and energy characteristics of a copper vapor laser (CVL) is considered. The process of relaxation of the lower laser levels in the inter-pulse period is shown to be the main physical factor determining the pulse repetition frequency of the laser. Fast relaxation of the lower levels determines the high energy potential of CVL. The prepulse electron density is, in essence, a technical factor limiting the efficiency of pumping the active medium. The effect of the prepulse electron density is caused by many reasons. In combination, they can determine a significant dependence of the CVL energy characteristics on the prepulse electron density. The revealing and excluding of these reasons will enhance the CVL performance.