The present invention provides a combination product, which comprises immediate release pellet of phentermine and sustained-release pellet of topiramate, wherein the pellet of topiramate includes: a) a blank pellet core b) an active drug layer that contains topiramate and is free of binding agent, the layer being located on surface of the blank pellet core c) a sustained-release coating layer containing ethyl cellulose and PVP K30, the sustained-release coating layer being located on external of the active drug layer. The present invention further discloses a method for preparing the combination product.
