In this paper, we investigate a method that combines beamforming (BF) with a per-antenna power constraint and adaptive peak-to-average power ratio (PAPR) reduction using the null space of a multiple-input multiple-output (MIMO) channel in multiuser massive MIMO-orthogonal frequency division multiplexing (OFDM) transmission. To improve the tradeoff between the throughput and PAPR, it is necessary to consider both mutually related BF control and PAPR reduction. In the proposed method, PAPR is first suppressed by generating a BF matrix that limits the transmission power variation among transmitter antennas using a firefly algorithm (FA). The subsequent adaptive PAPR reduction processing further reduces the PAPR while mitigating the data throughput degradation due to the interference from the PAPR reduction signal generated by the clipping and filtering (CF) algorithm. This is accomplished by restricting the transmission of the PAPR reduction signal only to the null space of the MIMO channel. Computer simulation results show that the proposed method improves the PAPR versus the throughput characteristics compared to the case using conventional zero forcing (ZF)-based BF.