Dr. Doug (or others) - Atopica Question

Well, the Tamaril P (sp?) isn't working so we're biting the bullet and trying the Atopica. My question is this: I already gave Jesse his dose of Tamaril P this morning. Should I wait until tomorrow to start the Atopica? Don't want to OD the poor pup. Forgot to ask the vet and they are closed. Thanks.