From the Guidelines
Lactic acidosis should be managed by addressing the underlying cause, discontinuing contributing medications such as metformin, and providing supportive care with fluid resuscitation, oxygen supplementation, and hemodynamic support as needed. The management of lactic acidosis involves a comprehensive approach to identify and treat the underlying cause, which may include sepsis, shock, severe hypoxemia, certain medications, or metabolic disorders. Initial management involves fluid resuscitation with isotonic crystalloids, oxygen supplementation, and hemodynamic support with vasopressors like norepinephrine if needed 1.
Key Considerations
- Discontinue any contributing medications such as metformin, particularly in patients with renal impairment 1.
- For severe cases with pH < 7.1, sodium bicarbonate may be considered, though its use remains controversial 1.
- Hemodialysis might be necessary for patients with drug-induced lactic acidosis or those with severe acidosis unresponsive to conventional therapy.
- Regular monitoring of arterial blood gases, lactate levels, and vital signs is essential to assess response to treatment.
Underlying Causes and Treatment
- Sepsis and shock require aggressive management with fluid resuscitation, antimicrobial therapy, and hemodynamic support 1.
- Severe hypoxemia requires oxygen supplementation and, if necessary, mechanical ventilation.
- Metabolic disorders may require specific treatments, such as insulin for diabetic ketoacidosis.
Monitoring and Supportive Care
- Serial lactate measurements can help predict survival and assess response to therapy 1.
- Base deficit values can also provide an indirect estimation of global tissue acidosis due to impaired perfusion 1.
- Supportive care includes maintaining normoglycemia, avoiding excessive glycolytic oxidation of glucose, and using lactate-free IV fluids in patients with mitochondrial disease 1.
From the FDA Drug Label
5 WARNINGS AND PRECAUTIONS
- 1 Lactic Acidosis There have been postmarketing cases of metformin-associated lactic acidosis, including fatal cases. These cases had a subtle onset and were accompanied by nonspecific symptoms such as malaise, myalgias, abdominal pain, respiratory distress, or increased somnolence; however, hypotension and resistant bradyarrhythmias have occurred with severe acidosis Metformin associated lactic acidosis was characterized by elevated blood lactate concentrations (>5 mmol/L), anion gap acidosis (without evidence of ketonuria or ketonemia), and an increased lactate: pyruvate ratio; metformin plasma levels were generally >5 mcg/mL Metformin decreases liver uptake of lactate increasing lactate blood levels which may increase the risk of lactic acidosis, especially in patients at risk.
Lactic Acidosis is a risk associated with metformin (PO) use, characterized by elevated blood lactate concentrations, anion gap acidosis, and increased lactate:pyruvate ratio.
- Risk factors for metformin-associated lactic acidosis include:
- Renal impairment
- Drug interactions that impair renal function or increase metformin accumulation
- Age 65 or greater
- Radiologic studies with contrast
- Symptoms of lactic acidosis may be nonspecific, including malaise, myalgias, abdominal pain, respiratory distress, or increased somnolence.
- Management of suspected metformin-associated lactic acidosis includes prompt discontinuation of metformin, general supportive measures, and hemodialysis to correct acidosis and remove accumulated metformin 2.
From the Research
Definition and Causes of Lactic Acidosis
- Lactic acidosis is a condition characterized by the accumulation of lactate in the body, leading to a decrease in blood pH [(3,4)].
- It can be caused by various factors, including tissue hypoxia, sepsis, and certain medications such as metformin [(3,4,5)].
- Type B lactic acidosis, also known as non-hypoxic lactic acidosis, can occur in the absence of tissue hypoxia and is often associated with underlying medical conditions or medications 6.
Diagnosis and Treatment
- The diagnosis of lactic acidosis is typically made based on the presence of elevated lactate levels and metabolic acidosis [(3,4)].
- Treatment of lactic acidosis usually involves addressing the underlying cause, such as sepsis or tissue hypoxia, and providing supportive care to manage symptoms [(3,4)].
- Buffering agents, such as sodium bicarbonate, may be used to help manage acidosis, but their effectiveness is still debated 4.
- In cases of metformin-associated lactic acidosis, hemodialysis and continuous bicarbonate infusion may be necessary to manage the condition 7.
Risk Factors and Prevention
- Certain patient populations, such as those with renal impairment or underlying medical conditions, are at increased risk of developing lactic acidosis [(5,7)].
- The use of metformin in patients with type 2 diabetes mellitus requires careful consideration of the potential risks and benefits, particularly in those with renal impairment [(5,7)].
- Regular monitoring of lactate levels and renal function can help identify patients at risk of developing lactic acidosis and allow for early intervention 5.