At what creatinine level should metformin be stopped?

NICE guidelines recommend 130 mmol/L of creatinine as a cut off for considering metformin discontinuation. Note word Guidelines. That is all it should be. Definitely a magic number out of some hat.  In the individual patient, depending on whether withdrawal of metformin would adversely influence short term and long term outcomes, I would tend to, and encourage my diabetes nurse to tend to, persevere with metformin. A creatinine above 200 mmol/L seems to be more reasonable to me, as slight fluctuations in the 120-170 range often settle or stay stable for a few more years. Given metformin's cardiovascular benefits in the obese, and the fact that renal impairment patients are even more at risk for cardiovascular events, I feel guideline revision is warranted. Withdrawing metformin and fighting a losing battle with rising sugars should give enough time for the osmotic diuresis and dehydration to worsen kidney failure in the short term!.  Where have all those EBM buffs gone when silly guidelines are put out?

Are oral hypoglycaemic agents safe in pregnancy?

A brave randomised controlled trial in 2000 suggested the safety of glyburide in pregnant gestational diabetics. N Engl J Med. 2000 Oct 19;343(16):1134-8.     Glyburide was not detected in the cord serum of any infant.   Recent studies seem to suggest equal efficacy of glyburide and insulin in gestational diabetes, although that comes as no surprise, since efficacy was never the actual issue. Instead safety seems to reasonable although concerns regarding preeclampsia have been raised in a recent retrospective  analysis.  Am J Obstet Gynecol. 2005 Jul;193(1):118-24.   Cost wise, glyburide may have benefits as well compared to insulin J Perinatol. 2002 Jul-Aug;22(5):403-6.    in addition to ease of use.

With regard to use of insulin sensitizers as metformin in pregnant patients with polycystic ovarian disease, the views are varied  Curr Opin Obstet Gynecol. 2004 Jun;16(3):245-50  in the absence of randomised control trials around which the whole world revolves these days. While miscarriage and gestational diabetes seem to be more common in polycystic ovary syndrome, evidence that these can be improved with metformin is awaited from trials in the future. Good old personal experiences supported by peer group experiences should still find a strong place in decision making to use these drugs while awaiting further evidence through trials. (personal view)  Remembering that "Absence of Evidence is not Evidence of Absence", is crucial to avoid denying the benefits of drugs that are "more likely" to be beneficial than harmful based on current evidence, while waiting years for delayed evidence to come through at the mercy of the  whims and competitions of pharmaceutical organisations. Metformin use seems safe during lactation as well.   MJA 2004; 181 (3): 174-175  Realistic sane practical advice  from Australia is available at MJA 2004; 180 (9): 462-464

Should all diabetics be on Aspirin?