Pharmacologically-induced metabolic acidosis: a review

Metabolic acidosis may occasionally develop in the course of treatment with drugs used in everyday clinical practice, as well as with the exposure to certain chemicals. Drug-induced metabolic acidosis, although usually mild, may well be life-threatening, as in cases of lactic acidosis complicating antiretroviral therapy or treatment with biguanides. Therefore, a detailed medical history, with special attention to the recent use of culprit medications, is essential in patients with acid-base derangements. Effective clinical management can be handled through awareness of the adverse effect of certain pharmaceutical compounds on the acid-base status. In this review, we evaluate relevant literature with regard to metabolic acidosis associated with specific drug treatment, and discuss the clinical setting and underlying pathophysiological mechanisms. These mechanisms involve renal inability to excrete the dietary H+ load (including types I and IV renal tubular acidoses), metabolic acidosis owing to increased H+ load (including lactic acidosis, ketoacidosis, ingestion of various substances, administration of hyperalimentation solutions and massive rhabdomyolysis) and metabolic acidosis due to HCO3- loss (including gastrointestinal loss and type II renal tubular acidosis). Determinations of arterial blood gases, the serum anion gap and, in some circumstances, the serum osmolar gap are helpful in delineating the pathogenesis of the acid-base disorder. In all cases of drug-related metabolic acidosis, discontinuation of the culprit medications and avoidance of readministration is advised.