A method and system for monitoring and/or controlling a glycemic state of a subject, comprising a housing device having one or more chambers, extendable and retractable sensors, extendable and retractable catheters, insulin reservoir, neuroprotective agent reservoir, release mechanism for releasing insulin and neuroprotective agent into the subject, and a control mechanism with a processor for receiving and analyzing outputs from the sensors and for controlling the release mechanism, a clock mechanism for providing logging and/or circadian information to the processor, an internal analysis chamber, a byproduct storage chamber, a sampling mechanism, a transfer mechanism, a self-sealing membrane, a calibration chamber, a replacement sensor chamber, a prevention mechanism to prevent deposition of unwanted substances on a sensor or catheter, a removal mechanism to remove unwanted substances from a sensor or catheter, a warning mechanism, a real-time clock and non-volatile memory to store and log information processed by the processor, a failure detection mechanism, and wired and/or wireless communication linkages both internally and externally.