La metformina es una biguanida ampliamente utilizada en el tratamiento de la diabetes mellitus tipo II. Entre los efectos secundarios derivados de su empleo destaca por su baja frecuencia de presentación pero potencial gravedad la acidosis láctica.
El diagnóstico de la misma se basa generalmente en la coexistencia de la acidosis láctica en un paciente en tratamiento con metformina con uno o mas factores de riesgo para la presentación de la misma. El desarrollo de acidosis láctica en relación con el tratamiento con metformina conlleva una mortalidad que oscila entre 50-80%. (Nutr Hosp. 2007;22:124-125)
Metformin lactic acidosis and anaesthesia: myth or reality?
Acta Anaesthesiol Belg;56(3):297-302
AIMS: To determine whether a causal or coincidental relationship is indicated in the literature between metaformin and lactic acidosis and to recommend clinicalguidelines for the withdrawal of metformin prior to surgery. METHOD: A broadreview of the literature related to metformin associated acidosis was carriedout. (There are few publications specifically related to metformin treatment and anaesthesiology). RESULTS: When metformin-associated lactic acidosis occurs, aconcurrent pathology or contraindication to the use of metformin is often found. Anaesthesia and surgery can generate or aggravate concurrent pathologies.CONCLUSION: Although no association has been shown between metformin and lacticacidosis under usual conditions of use, vigilance is required when metformin isused prior to surgery. The following clinical guideline is proposed: to withdraw (when possible) metformin 48 hours prior to surgery and to wait until thepatient's biological and clinical parameters return to normal beforereintroducing it.
Metformin-associated lactic acidosis
Ann Fr Anesth Reanim2006;25(10):1046-52
OBJECTIVE: The aims of this review are to precise the pathophysiologicalmechanisms leading to biguanide-associated lactic acidosis, to give elements ofdiagnosis, and to underline the precautionary conditions for prescribing thesedrugs by an improvement in physicians and patient's education. DATA SOURCES: APubMed database research in English and French language reports published untilDecember 2005. The keywords were: lactic acidosis, metformin, biguanide, diabetesmellitus. DATA EXTRACTION: Data in selected articles were reviewed, clinical and basic science research relevant informations were extracted. DATA SYNTHESIS:Metformin, which is an oral antidiabetic agent, is the only one biguanideavailable in France. It acts by enhancing the sensitivity to insulin by adecrease in the hepatic glucose production and an increase in its peripheral use.In term of glycemic control, it has the same efficiency than the otherhypoglycemic agents. It represents the treatment of choice for overweight type 2 diabetic patients because of its beneficial effects on the weight loss and on thecardiovascular complications. The incidence of metformin-associated lacticacidosis is very low when contra-indications and appropriate rules forprescribing this drug are respected. The relationship between metformin andlactic acidosis remains largely controversial. In practical, we can distinguishthree situations which have different prognosis. In the first case, metforminseems to be responsible for lactic acidosis because of self-poisoning oraccidental overdose, and prognosis is good. In the second case, the associationbetween metformin and lactic acidosis is coincidental rather than causal, and maybe induced by an underlying organ failure. In the last case there is a cause oflactic acidosis which is worsened by a precipitating factor leading to metformin accumulation. The 2 latter situations are very severe as mortality rate is about 50%. Symptomatic treatments and renal replacement therapy which allows metformin removal are the curative treatment. Prevention is essential. It requires therespect of metformin contraindications and a better education of physicians andpatients for a safe prescription. CONCLUSION: Due to its beneficial effects,metformin is the gold standard treatment for overweight type 2 diabetic patients.The essential precautionary conditions for prescribing metformin as well as therespect of its contra-indications permit largely to prevent lactic acidosis. Thiscomplication is serious when it is associated with intercurrent illnesses andmetformin accumulation. The curative treatment is based on renal replacementtherapy. Prevention only rests on the respect of the contra-indications.Education of physicians and patients concerning the rules of prescription remainsessential.
