Methods, formulations, and devices are provided for enhancing drug delivery from a medical device. The method is provided for increasing the rate or quantity of a drug formulation released from an implantable drug delivery device, which method comprises the step of providing a release-modifying agent within or proximate to the implantable drug delivery device, in a manner effective to inhibit gelation, aggregation, or precipitation of the drug formulation being released from the device. The drug formulation and the release-modifying agent may be stored together in at least one reservoir in the implantable drug deliver device. Alternatively, the release-modifying agent may be stored in one or more reservoirs separate from the drug formulation.