Haemolytic anaemia due to metformin

Metformin-Induced Hemolysis in a Glucose-6-Phosphate Dehydrogenase-Deficient Patient: A Case Report

Metformin is a first-line medication used in the treatment of type 2 diabetes mellitus along with other conditions such as insulin resistance and polycystic ovarian syndrome. Overall, metformin appears to be well tolerated with a low incidence of side effects; however, in certain high-risk populations, it can trigger a hemolytic crisis. This case report describes a middle-aged man who was initiated on metformin for new-onset diabetes, following which he had an acute hemoglobin drop and was diagnosed to be having a hemolytic crisis requiring hospitalization. He was diagnosed with a deficiency of the enzyme glucose-6-phosphate dehydrogenase (G6PD) on admission. Extensive workup was done to rule out other causes of hemolysis, all of which came back to be negative. The offending agent was stopped and the patient received supportive care after which he improved. This case highlights a rare, yet important, side effect of metformin that needs to be observed in certain individuals, especially patients with G6PD deficiency. Routine testing of high-risk populations known to be G6PD deficient should be considered before initiating metformin.

Metformin as a Fetal Hemoglobin Inducer in Non-transfusion Dependent Thalassemia Patients

Non-transfusion dependent thalassemia (NTDT) refers to a group of thalassemic disorders who do not need regular transfusions for survival, however it may be needed in certain conditions. Metformin was reported as a potential fetal hemoglobin (HbF) inducing agent in vitro but its efficacy and safety in vivo was not fully studied. This is a prospective interventional study aimed at studying the effect of metformin on HbF change in NTDT.

METHODS

Patients with established diagnosis of NTDT were enrolled. They were receiving a stable fixed dose of Hydroxyurea over the last 3 months. Patients were divided into two groups: a group that received Metformin for 6 months (Metformin group) and a control group. Complete blood picture, reticulocytic count, hemoglobin electrophoresis, liver enzymes, bilirubin, kidney functions, LDH and random blood sugar were performed at onset, 3 and 6 months of the study. All adverse events were recorded.

RESULTS

Forty two patients aged 12-23 years were enrolled. Metformin intake over 6 months did not show any statistically significant difference in clinical or the laboratory variables of efficacy when compared to the control group apart from reticulocytic count which was higher in Metformin group throughout the study.

CONCLUSION

Metformin intake, in addition to hydroxyurea, did not yield any extra benefit among patients with NTDT.

Severe hemolysis with negative direct antiglobulin test: A case report

A 49-year-old woman with type 2 diabetes mellitus (T2DM) presented to the emergency department. Her examination showed marked pallor, exhaustion, lethargy, yellowish eyes, anorexia, nausea and vomiting.

Hematuria; negative standard direct antiglobulin test (DAT); normal glucose 6 phosphate dehydrogenase (G6PD); hemoglobin (Hb), 4.8 g/dl; Mean cell volume (MCV), 91fl; platelet count, 233 × 10⁶/L; Total bilirubin, 7.0 mg/dl; Glucose, 316 mg/dl; lactate dehydrogenase (LDH), 1750U/L. Undoubtedly, therapeutic panel should have been used for hemolytic anemia. Intravenous (IV) fluids and 2 units of packed cell were transfused. Methylprednisolone with rituximab were started for the patient. After 3 weeks of the patient admission, she was discharged home with stable vital signs and Hb, 10 g/dl. We concluded in the cases that presented along with a severe drop in Hb and evidence of hemolysis which non immune hemolytic anemia is excluded in spite of negative standard DAT limited transfusion besides corticosteroids combined with rituximab, could be helpful in saving the patient.

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Autoimmune hemolytic anemia (AIHA) is caused by increased erythrocyte destruction with autoantibodies directed against the person's own red blood cells and susceptible them to lyse and consequent insufficient number of red blood cells in the circulation.

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A diagnosis of DAT-negative AIHA can be made following careful exclusion of alternative causes of hemolysis, and confirmation by a sensitive technique and by a response to steroid therapy.

Review of Biguanide (Metformin) Toxicity

In the 1920s, guanidine, the active component of Galega officinalis, was shown to lower glucose levels and used to synthesize several antidiabetic compounds. Metformin (1,1 dimethylbiguanide) is the most well-known and currently the only marketed biguanide in the United States, United Kingdom, Canada, and Australia for the treatment of non-insulin-dependent diabetes mellitus. Although phenformin was removed from the US market in the 1970s, it is still available around the world and can be found in unregulated herbal supplements. Adverse events associated with therapeutic use of biguanides include gastrointestinal upset, vitamin B₁₂ deficiency, and hemolytic anemia. Although the incidence is low, metformin toxicity can lead to hyperlactatemia and metabolic acidosis. Since metformin is predominantly eliminated from the body by the kidneys, toxicity can occur when metformin accumulates due to poor clearance from renal insufficiency or in the overdose setting. The dominant source of metabolic acidosis associated with hyperlactatemia in metformin toxicity is the rapid cytosolic adenosine triphosphate (ATP) turnover when complex I is inhibited and oxidative phosphorylation cannot adequately recycle the vast quantity of H+ from ATP hydrolysis. Although metabolic acidosis and hyperlactatemia are markers of metformin toxicity, the degree of hyperlactatemia and severity of acidemia have not been shown to be of prognostic value. Regardless of the etiology of toxicity, treatment should include supportive care and consideration for adjunct therapies such as gastrointestinal decontamination, glucose and insulin, alkalinization, extracorporeal techniques to reduce metformin body burden, and metabolic rescue.

Diabetes mellitus and advanced liver fibrosis are risk factors for severe anaemia during telaprevir-based triple therapy

BACKGROUND & AIMS

Adding telaprevir to pegylated-interferon and ribavirin increased both response rates and side effects of hepatitis C virus (HCV) treatment. We identified variables associated with severe anaemia during telaprevir-based triple therapy.

METHODS

An observational study was performed on 142 HCV-infected patients between June 2011 and March 2012. All subjects completed 12 weeks of telaprevir-based triple therapy or discontinued early because of anaemia. Severe anaemia was defined by a haemoglobin≤8.9 g/dl; advanced fibrosis was determined by Fib-4≥3.25.

RESULTS

The 47 (33%) patients who developed severe anaemia were similar to those who did not in sex, race, and prior response to dual therapy, but they were more likely to have diabetes (23.4% vs. 6.3%, P<0.01), advanced fibrosis (46.8% vs. 29.5%, P=0.04) and a history of anaemia during previous dual therapy (29.7% vs. 11.4%, P=0.02). Patients developing severe anaemia were older (59 vs. 56 years, P=0.02), had lower baseline platelet counts (134 vs. 163×10(9) /L, P=0.04), haemoglobin (14.0 vs. 15.0 g/dl, P<0.01), estimated glomerular filtration rate (79 vs. 90 ml/min/1.73 m2, P=0.03) and a higher median ribavirin/weight ratio (14.9 vs. 13.2 mg/kg, P<0.01). In multivariable logistic regression, presence of diabetes (OR=5.61, 95% CI: 1.59-19.72), Fib-4≥3.25 (OR=3.09, 95% CI: 1.28-7.46), higher ribavirin/weight ratio (OR=1.31 per mg/kg, 95% CI: 1.13-1.52) and lower baseline haemoglobin (OR=0.57 per g/dl, 95% CI, 0.41-0.80) were independently associated with developing severe anaemia.

CONCLUSIONS

Severe anaemia occurred in one-third of patients receiving telaprevir-based triple therapy. Risk was greater in patients with diabetes, advanced liver fibrosis, higher ribavirin/weight ratio and lower baseline haemoglobin.

Anaemia, a common but often unrecognized risk in diabetic patients: a review

Anaemia in patients with diabetes, both type 1 and type 2, is a frequent clinical finding. The mechanisms of anaemia are multifactorial and often not very well understood. Iatrogenic causes, including oral antidiabetic drugs, ACE inhibitors and ARBs, and renal insufficiency are the major causes of anaemia in patients with type 2 diabetes. In patients with type 1, the cause is often an associated autoimmune disease, and screening for autoimmune gastritis, pernicious anaemia, Hashimoto's thyroiditis, coeliac disease and Addison's disease is recommended. Other rare causes - including G6PD deficiency, microangiopathic haemolytic anaemia and thiamine-responsive megaloblastic anaemia - should be suspected in young patients or when the classical causes are excluded. Early detection and recognition of the cause(s) of anaemia in patients with diabetes could help to prevent other clinical manifestations as well as the complications of diabetes.

Metformin-induced hemolytic anemia

OBJECTIVE

To report a rare side effect of metformin, an oral antidiabetic drug that is used for the treatment of type 2 diabetes mellitus.

CLINICAL PRESENTATION AND INTERVENTION

A 17-year-old boy was hospitalized for receiving acute lymphoblastic leukemia treatment that was composed of vincristine, L-asparaginase, daunorubicin, and prednisone. Hyperglycemia was determined without any clinical sign and metformin was started for steroid-induced insulin resistance. On the second day of metformin treatment, the patient's hemoglobin level decreased, and a direct Coombs test was positive for immunoglobulin G but negative for complement. An indirect Coombs test was negative. The glucose-6-phosphate dehydrogenase level was within the normal range. Drug-induced hemolytic anemia was suspected and metformin was discontinued. The jaundice gradually disappeared and there was no requirement for red blood cell transfusions.

CONCLUSION

This case showed that physicians should be aware of the potential side effect of metformin although it is infrequent.

Metformin: an old but still the best treatment for type 2 diabetes

The management of T2DM requires aggressive treatment to achieve glycemic and cardiovascular risk factor goals. In this setting, metformin, an old and widely accepted first line agent, stands out not only for its antihyperglycemic properties but also for its effects beyond glycemic control such as improvements in endothelial dysfunction, hemostasis and oxidative stress, insulin resistance, lipid profiles, and fat redistribution. These properties may have contributed to the decrease of adverse cardiovascular outcomes otherwise not attributable to metformin's mere antihyperglycemic effects. Several other classes of oral antidiabetic agents have been recently launched, introducing the need to evaluate the role of metformin as initial therapy and in combination with these newer drugs. There is increasing evidence from in vivo and in vitro studies supporting its anti-proliferative role in cancer and possibly a neuroprotective effect. Metformin's negligible risk of hypoglycemia in monotherapy and few drug interactions of clinical relevance give this drug a high safety profile. The tolerability of metformin may be improved by using an appropiate dose titration, starting with low doses, so that side-effects can be minimized or by switching to an extended release form. We reviewed the role of metformin in the treatment of patients with type 2 diabetes and describe the additional benefits beyond its glycemic effect. We also discuss its potential role for a variety of insulin resistant and pre-diabetic states, obesity, metabolic abnormalities associated with HIV disease, gestational diabetes, cancer, and neuroprotection.

Metformin poisoning: A complex presentation

The objective of this case report is to highlight presentation, complications and treatment of metformin poisoning. Patient after ingestion of 45gms of metformin developed colicky abdominal pain, severe tachypnea and vomiting. He developed severe lactic acidosis, cardiac arrest, pancreatitis and hemolytic anemia which was treated with charcoal, sodium bicarbonate, early initiation of high volume continuous veno-venous hemofiltration and supportive therapy. Metformin poisoning is a rare presentation and we discuss course of events in the management of metformin poisoning and its associated complications.

Fatal hemolytic anemia associated with metformin: a case report

Introduction

Metformin is a widely prescribed biguanide antidiabetic drug that has been implicated as a cause of hemolytic anemia in three previous case reports. We report a case of rapidly fatal hemolysis that was temporally associated with the initiation of metformin treatment for diabetes. Clinicians need to be aware of this rare but potentially serious side effect of metformin.

Case presentation

A 56-year-old Caucasian man with type 2 diabetes mellitus was started on metformin to improve glycemic control. Shortly afterwards, he developed progressive fatigue, exertional dyspnea, cranberry-colored urine and jaundice. Laboratory studies showed severe hemolysis, with a drop in hemoglobin from 14.7 to 6.6 g/dl over 4 days, markedly elevated lactate dehydrogenase, bilirubin and reticulocyte counts, and a low haptoglobin level. A peripheral blood smear showed no schistocytes, and a direct Coombs test was positive for anti-IgG and negative for anti-C3. Despite corticosteroid treatment and transfusion of packed red blood cells, the patient developed increasing dyspnea, hypotension, further decline in hemoglobin to 3.3 g/dl, and fatal cardiorespiratory arrest 12 hours after admission.

Conclusion

The serologic findings in this case suggest an autoimmune hemolytic anemia, caused either by a drug-induced autoantibody or a warm autoantibody. Based on the temporal association with metformin and the lack of other clear precipitating causes, we propose that metformin-induced hemolysis with a drug-induced autoantibody is a strong possibility. This mechanism differs from a previously described case with a possible antibody to the erythrocyte-drug complex. It has been shown, however, that hemolysis may occur via multiple mechanisms from the same drug. Clinicians should consider the possibility of metformin-associated immune hemolytic anemia in patients with otherwise unexplained hemolysis.

Metformin-associated lactic acidosis treated with continuous renal replacement therapy

INTRODUCTION

Lactic acidosis is an infrequent complication of metformin therapy for diabetes mellitus. The presence of clinical conditions, such as renal failure, increases the risk of metformin-associated lactic acidosis (MALA). We present a case of lactic acidosis in a patient with diabetes treated with metformin, complicated by acute renal failure in preexisting chronic nephropathy.

CASE SUMMARY

A 70-year-old white male, weighing 77 kg, with diabetes mellitus, coronary heart disease, congestive heart failure (New York Heart Association class III), moderate essential hypertension (stage 2), and renal dysfunction (serum urea, 90 mg/dL; serum creatinine, 1.5 mg/dL; creatinine clearance, 49.8 mL/min/1.73 m2) presented to the emergency department of the General Hospital of Rhodes (Rhodes, Greece), complaining of malaise, respiratory distress, myalgias, disorientation, abdominal discomfort, and increasing somnolence of insidious onset. The patient's regimen included isosorbide mononitrate 60 mg QD, furosemide 40 mg QD, quinapril 20 mg QD, and metformin 850 mg TID. Before this hospitalization, he had received a 2-week course of oral diclofenac sodium 25 mg TID for low back pain. Preliminary laboratory evaluation found leukocytosis (27,300/mm3), severe renal failure (serum urea, 215 mg/dL; serum creatinine, 7.4 mg/dL; calculated creatinine clearance, 10.1 mL/min/1.73 m2), and a high anion gap metabolic acidosis (pH, 6.95; anion gap, 33 mEq/L) in arterial blood gas analysis. His medical and drug history, the clinical and laboratory findings, and the determination of lactate in samples of plasma (7.8 mEq/L), aroused the suspicion of MALA. The Naranjo algorithm scores for metformin and diclofenac sodium were 6 and 7, respectively. The patient received a single session of bicarbonate-buffered continuous venovenous hemodiafiltration (CWHDF) that lasted 16 hours. Ultimately, he was stabilized, and progressive restoration of acid-base balance and renal function was observed.

DISCUSSION

We suspect that lactic acidosis may have been related to the use of metformin, the presence of heart and renal failure (contributing to metformin toxicity), and previous use of diclofenac sodium. CVVHDF has an advantage over conventional intermittent hemodialysis in that it corrects acidosis and removes lactate and metformin without risk of hypernatremia or fluid overload.

CONCLUSIONS

MALA should be strongly suspected in diabetic patients presenting with high anion gap metabolic acidosis and increased serum lactate level. In the case described, prompt recognition of lactic acidosis and early application of bicarbonate-buffered CVVHDF produced successful results.