We present a generalized Drude analysis of the in-plane optical conductivity ab ͑T , ͒ in cuprates taking into account the effects of in-plane anisotropy. A simple ansatz for the scattering rate ⌫͑T , ͒, that includes anisotropy, a quadratic frequency dependence, and saturation at the Mott-Ioffe-Regel limit, is able to reproduce recent normal state data on an optimally doped cuprate over a wide frequency range. We highlight the potential importance of including anisotropy in the full expression for ab ͑T , ͒ and challenge previous determinations of ⌫͑͒ in which anisotropy was neglected and ⌫͑͒ was indicated to be strictly linear in frequency over a wide frequency range. Possible implications of our findings for understanding thermodynamic properties and self-energy effects in high-T c cuprates will also be discussed.