I am not a vet...yet...but I jost wrote a paper on ferret insulinomas regarding treatment. Side effects of Diazoxide include anorexia, vomitting, diarrhea, tachycardia, hematologic abnormalities.... I did not read anywhere that it causes weakness. Perhaps the immediate weakness that you are talking about is due to a persistent hypoglycemia and perhaps the dose of diazoxide should be increased. Weakness, ataxia, and lethargy are some of the clinical signs of hypoglycemia. Diazoxide does directly inhibit insulin secretion but it also stimulates the beta-adrenergic system, stimulating epinephrine which increases hepatic glycogenolysis and glucogenesis, and decrease the uptake of glucose by peripheral cells. If the dose of diazoxide can't be increased, a combination therapy of prednisone and diazoxide could be tried....then of course there is always surgery... [Posted in FML issue 1551]