<prompt> Niacin is dangerous in diabetes mellitus because:It causes insulin resistanceIt causes sudden hypoglycemiaIt decreases glucagon secretionIt decreases effect of other OHA  <response>: Ans. a. It causes insulin resistanceRef: Goodman Gilman 12th eP 900Niacin causes insulin resistance and hence causes severe hyperglycemia in patients of diabetes mellitus.Hence it should be avoided in patients of diabetes mellitus. 