Using fitglm for overdispersed Poisson models

Hello,

Is it possible to fit an overdispersed Poisson model using fitglm? An overdispersed Poisson model is a Poisson model with variance = phi*mean, where phi > 1, rather than variance = mean as in a Poisson model. I don't see how to do this using the "formula" parameter. I can write out the quasilikelihood for this if fitglm doesn't handle it.