Diazoxide interferes with insulin release through its action on potassium channels. The efflux of potassium, as an effect of Diazoxide, will lead to hyperpolarization of cell membrane that leads to decrease calcium influx. The low calcium will decrease the release of insulin. Therefore this medicine is not given to non-insulin dependent diabetic patients.
^van Hamersvelt HW, Kloke HJ, de Jong DJ, Koene RA, Huysmans FT (August 1996). "Oedema formation with the vasodilators nifedipine and diazoxide: direct local effect or sodium retention?". J. Hypertens.14 (8): 1041–5. doi:10.1097/00004872-199608000-00016. PMID8884561.