Before using cephalexin, tell your doctor if you are using any of the following drugs:

    *      a blood thinner such as warfarin (Coumadin);
    *      metformin (Fortamet, Glucophage, Riomet, Actoplus, Avandamet, Metaglip); or
    *      probenecid (Benemid).

This list is not complete and there may be other drugs that can interact with cephalexin. Tell your doctor about all the prescription and over-the-counter medications you use. This includes vitamins, minerals, herbal products, and drugs prescribed by other doctors. Do not start using a new medication without telling your doctor.