Drug Interactions between metformin and Vitamin C

MetFORMIN should be taken with meals, and excessive alcohol intake (either short-term binge drinking or frequent consumption) should be avoided during treatment. Taking metFORMIN with alcohol may increase the risk of a rare but serious and potentially life-threatening condition known as lactic acidosis, which is a buildup of lactic acid in the blood that can occasionally occur during treatment with metformin-containing products. Lactic acidosis is more likely to occur if you have kidney or liver disease, acute or unstable congestive heart failure, or dehydration. You should seek immediate medical attention if you develop potential signs and symptoms of lactic acidosis such as fatigue, weakness, muscle pain, increasing drowsiness, abdominal pain or discomfort, slow or irregular heartbeat, breathing difficulty, chills, and other unusual symptoms. Alcohol may also affect blood glucose levels in patients with diabetes. Both hypoglycemia (low blood sugar) and hyperglycemia (high blood sugar) may occur, depending on how much and how often you drink. You should avoid using alcohol if your diabetes is not well controlled or if you have high triglycerides, neuropathy (nerve damage), or pancreatitis. Moderate alcohol consumption generally does not affect blood glucose levels if your diabetes is under control. However, you should limit your alcohol intake due to the risk of lactic acidosis with metformin. Avoid drinking alcohol on an empty stomach or following exercise, as it may increase the risk of hypoglycemia. Talk to your doctor or pharmacist if you have any questions or concerns about metformin.

Metformin is contraindicated in patients with acute or chronic metabolic acidosis (including diabetic ketoacidosis) with or without coma. Postmarketing cases of metformin-associated lactic acidosis have resulted in death, hypothermia, hypotension, and resistant bradyarrhythmias. Risk factors include renal dysfunction, age 65 years and older, hypoxic states, excessive alcohol intake, and liver dysfunction. Lactic acidosis has been associated with metformin accumulation in plasma at levels generally exceeding 5 mcg/mL. The risk of metformin-associated lactic acidosis increases with the patient's age because patients 65 years and older have a greater likelihood of having hepatic, renal, or cardiac impairment. Renal function should be assessed more frequently in older adult patients. Several postmarketing cases of metformin-associated lactic acidosis occurred in the setting of acute congestive heart failure, especially when accompanied by hypoperfusion and hypoxemia; cardiovascular collapse (shock), acute myocardial infarction, sepsis, and other conditions associated with hypoxemia (e.g., severe anemia, asphyxia) have been associated with lactic acidosis and may cause prerenal azotemia. When such an event occurs, metformin should be discontinued. Dehydration (e.g., severe diarrhea or vomiting) may increase the risk for volume depletion, hypotension, and renal impairment; such patients may be at increased risk for lactic acidosis. Alcohol potentiates the effect of metformin on lactate metabolism; patients should be advised against excessive alcohol intake while receiving metformin. All patients treated with metformin should have renal function monitored regularly (at least annually or more frequently if necessary). If metformin-associated lactic acidosis is suspected, general supportive measures should be instituted promptly in a hospital setting, as well as immediate discontinuation of metformin. If lactic acidosis is diagnosed or strongly suspected, prompt hemodialysis is recommended to correct the acidosis and remove accumulated metformin. Patients and their families should be educated about the symptoms of lactic acidosis and, if these symptoms occur, they should be instructed to discontinue metformin and contact their health care provider.

Metformin is contraindicated in patients with acute or chronic metabolic acidosis (including diabetic ketoacidosis) with or without coma. Postmarketing cases of metformin-associated lactic acidosis have resulted in death, hypothermia, hypotension, and resistant bradyarrhythmias. Risk factors include renal dysfunction, age 65 years and older, hypoxic states, excessive alcohol intake, and liver dysfunction. Lactic acidosis has been associated with metformin accumulation in plasma at levels generally exceeding 5 mcg/mL. The risk of metformin-associated lactic acidosis increases with the patient's age because patients 65 years and older have a greater likelihood of having hepatic, renal, or cardiac impairment. Renal function should be assessed more frequently in older adult patients. Several postmarketing cases of metformin-associated lactic acidosis occurred in the setting of acute congestive heart failure, especially when accompanied by hypoperfusion and hypoxemia; cardiovascular collapse (shock), acute myocardial infarction, sepsis, and other conditions associated with hypoxemia (e.g., severe anemia, asphyxia) have been associated with lactic acidosis and may cause prerenal azotemia. When such an event occurs, metformin should be discontinued. Dehydration (e.g., severe diarrhea or vomiting) may increase the risk for volume depletion, hypotension, and renal impairment; such patients may be at increased risk for lactic acidosis. Alcohol potentiates the effect of metformin on lactate metabolism; patients should be advised against excessive alcohol intake while receiving metformin. All patients treated with metformin should have renal function monitored regularly (at least annually or more frequently if necessary). If metformin-associated lactic acidosis is suspected, general supportive measures should be instituted promptly in a hospital setting, as well as immediate discontinuation of metformin. If lactic acidosis is diagnosed or strongly suspected, prompt hemodialysis is recommended to correct the acidosis and remove accumulated metformin. Patients and their families should be educated about the symptoms of lactic acidosis and, if these symptoms occur, they should be instructed to discontinue metformin and contact their health care provider.

Metformin is contraindicated in patients with acute or chronic metabolic acidosis (including diabetic ketoacidosis) with or without coma. Postmarketing cases of metformin-associated lactic acidosis have resulted in death, hypothermia, hypotension, and resistant bradyarrhythmias. Risk factors include renal dysfunction, age 65 years and older, hypoxic states, excessive alcohol intake, and liver dysfunction. Lactic acidosis has been associated with metformin accumulation in plasma at levels generally exceeding 5 mcg/mL. The risk of metformin-associated lactic acidosis increases with the patient's age because patients 65 years and older have a greater likelihood of having hepatic, renal, or cardiac impairment. Renal function should be assessed more frequently in older adult patients. Several postmarketing cases of metformin-associated lactic acidosis occurred in the setting of acute congestive heart failure, especially when accompanied by hypoperfusion and hypoxemia; cardiovascular collapse (shock), acute myocardial infarction, sepsis, and other conditions associated with hypoxemia (e.g., severe anemia, asphyxia) have been associated with lactic acidosis and may cause prerenal azotemia. When such an event occurs, metformin should be discontinued. Dehydration (e.g., severe diarrhea or vomiting) may increase the risk for volume depletion, hypotension, and renal impairment; such patients may be at increased risk for lactic acidosis. Alcohol potentiates the effect of metformin on lactate metabolism; patients should be advised against excessive alcohol intake while receiving metformin. All patients treated with metformin should have renal function monitored regularly (at least annually or more frequently if necessary). If metformin-associated lactic acidosis is suspected, general supportive measures should be instituted promptly in a hospital setting, as well as immediate discontinuation of metformin. If lactic acidosis is diagnosed or strongly suspected, prompt hemodialysis is recommended to correct the acidosis and remove accumulated metformin. Patients and their families should be educated about the symptoms of lactic acidosis and, if these symptoms occur, they should be instructed to discontinue metformin and contact their health care provider.

Metformin is contraindicated in patients with acute or chronic metabolic acidosis (including diabetic ketoacidosis) with or without coma. Postmarketing cases of metformin-associated lactic acidosis have resulted in death, hypothermia, hypotension, and resistant bradyarrhythmias. Risk factors include renal dysfunction, age 65 years and older, hypoxic states, excessive alcohol intake, and liver dysfunction. Lactic acidosis has been associated with metformin accumulation in plasma at levels generally exceeding 5 mcg/mL. The risk of metformin-associated lactic acidosis increases with the patient's age because patients 65 years and older have a greater likelihood of having hepatic, renal, or cardiac impairment. Renal function should be assessed more frequently in older adult patients. Several postmarketing cases of metformin-associated lactic acidosis occurred in the setting of acute congestive heart failure, especially when accompanied by hypoperfusion and hypoxemia; cardiovascular collapse (shock), acute myocardial infarction, sepsis, and other conditions associated with hypoxemia (e.g., severe anemia, asphyxia) have been associated with lactic acidosis and may cause prerenal azotemia. When such an event occurs, metformin should be discontinued. Dehydration (e.g., severe diarrhea or vomiting) may increase the risk for volume depletion, hypotension, and renal impairment; such patients may be at increased risk for lactic acidosis. Alcohol potentiates the effect of metformin on lactate metabolism; patients should be advised against excessive alcohol intake while receiving metformin. All patients treated with metformin should have renal function monitored regularly (at least annually or more frequently if necessary). If metformin-associated lactic acidosis is suspected, general supportive measures should be instituted promptly in a hospital setting, as well as immediate discontinuation of metformin. If lactic acidosis is diagnosed or strongly suspected, prompt hemodialysis is recommended to correct the acidosis and remove accumulated metformin. Patients and their families should be educated about the symptoms of lactic acidosis and, if these symptoms occur, they should be instructed to discontinue metformin and contact their health care provider.

Metformin is contraindicated in patients with acute or chronic metabolic acidosis (including diabetic ketoacidosis) with or without coma. Postmarketing cases of metformin-associated lactic acidosis have resulted in death, hypothermia, hypotension, and resistant bradyarrhythmias. Risk factors include renal dysfunction, age 65 years and older, hypoxic states, excessive alcohol intake, and liver dysfunction. Lactic acidosis has been associated with metformin accumulation in plasma at levels generally exceeding 5 mcg/mL. The risk of metformin-associated lactic acidosis increases with the patient's age because patients 65 years and older have a greater likelihood of having hepatic, renal, or cardiac impairment. Renal function should be assessed more frequently in older adult patients. Several postmarketing cases of metformin-associated lactic acidosis occurred in the setting of acute congestive heart failure, especially when accompanied by hypoperfusion and hypoxemia; cardiovascular collapse (shock), acute myocardial infarction, sepsis, and other conditions associated with hypoxemia (e.g., severe anemia, asphyxia) have been associated with lactic acidosis and may cause prerenal azotemia. When such an event occurs, metformin should be discontinued. Dehydration (e.g., severe diarrhea or vomiting) may increase the risk for volume depletion, hypotension, and renal impairment; such patients may be at increased risk for lactic acidosis. Alcohol potentiates the effect of metformin on lactate metabolism; patients should be advised against excessive alcohol intake while receiving metformin. All patients treated with metformin should have renal function monitored regularly (at least annually or more frequently if necessary). If metformin-associated lactic acidosis is suspected, general supportive measures should be instituted promptly in a hospital setting, as well as immediate discontinuation of metformin. If lactic acidosis is diagnosed or strongly suspected, prompt hemodialysis is recommended to correct the acidosis and remove accumulated metformin. Patients and their families should be educated about the symptoms of lactic acidosis and, if these symptoms occur, they should be instructed to discontinue metformin and contact their health care provider.

Metformin is contraindicated in patients with acute or chronic metabolic acidosis (including diabetic ketoacidosis) with or without coma. Postmarketing cases of metformin-associated lactic acidosis have resulted in death, hypothermia, hypotension, and resistant bradyarrhythmias. Risk factors include renal dysfunction, age 65 years and older, hypoxic states, excessive alcohol intake, and liver dysfunction. Lactic acidosis has been associated with metformin accumulation in plasma at levels generally exceeding 5 mcg/mL. The risk of metformin-associated lactic acidosis increases with the patient's age because patients 65 years and older have a greater likelihood of having hepatic, renal, or cardiac impairment. Renal function should be assessed more frequently in older adult patients. Several postmarketing cases of metformin-associated lactic acidosis occurred in the setting of acute congestive heart failure, especially when accompanied by hypoperfusion and hypoxemia; cardiovascular collapse (shock), acute myocardial infarction, sepsis, and other conditions associated with hypoxemia (e.g., severe anemia, asphyxia) have been associated with lactic acidosis and may cause prerenal azotemia. When such an event occurs, metformin should be discontinued. Dehydration (e.g., severe diarrhea or vomiting) may increase the risk for volume depletion, hypotension, and renal impairment; such patients may be at increased risk for lactic acidosis. Alcohol potentiates the effect of metformin on lactate metabolism; patients should be advised against excessive alcohol intake while receiving metformin. All patients treated with metformin should have renal function monitored regularly (at least annually or more frequently if necessary). If metformin-associated lactic acidosis is suspected, general supportive measures should be instituted promptly in a hospital setting, as well as immediate discontinuation of metformin. If lactic acidosis is diagnosed or strongly suspected, prompt hemodialysis is recommended to correct the acidosis and remove accumulated metformin. Patients and their families should be educated about the symptoms of lactic acidosis and, if these symptoms occur, they should be instructed to discontinue metformin and contact their health care provider.

Metformin is contraindicated in patients with acute or chronic metabolic acidosis (including diabetic ketoacidosis) with or without coma. Postmarketing cases of metformin-associated lactic acidosis have resulted in death, hypothermia, hypotension, and resistant bradyarrhythmias. Risk factors include renal dysfunction, age 65 years and older, hypoxic states, excessive alcohol intake, and liver dysfunction. Lactic acidosis has been associated with metformin accumulation in plasma at levels generally exceeding 5 mcg/mL. The risk of metformin-associated lactic acidosis increases with the patient's age because patients 65 years and older have a greater likelihood of having hepatic, renal, or cardiac impairment. Renal function should be assessed more frequently in older adult patients. Several postmarketing cases of metformin-associated lactic acidosis occurred in the setting of acute congestive heart failure, especially when accompanied by hypoperfusion and hypoxemia; cardiovascular collapse (shock), acute myocardial infarction, sepsis, and other conditions associated with hypoxemia (e.g., severe anemia, asphyxia) have been associated with lactic acidosis and may cause prerenal azotemia. When such an event occurs, metformin should be discontinued. Dehydration (e.g., severe diarrhea or vomiting) may increase the risk for volume depletion, hypotension, and renal impairment; such patients may be at increased risk for lactic acidosis. Alcohol potentiates the effect of metformin on lactate metabolism; patients should be advised against excessive alcohol intake while receiving metformin. All patients treated with metformin should have renal function monitored regularly (at least annually or more frequently if necessary). If metformin-associated lactic acidosis is suspected, general supportive measures should be instituted promptly in a hospital setting, as well as immediate discontinuation of metformin. If lactic acidosis is diagnosed or strongly suspected, prompt hemodialysis is recommended to correct the acidosis and remove accumulated metformin. Patients and their families should be educated about the symptoms of lactic acidosis and, if these symptoms occur, they should be instructed to discontinue metformin and contact their health care provider.

Metformin is contraindicated in patients with acute or chronic metabolic acidosis (including diabetic ketoacidosis) with or without coma. Postmarketing cases of metformin-associated lactic acidosis have resulted in death, hypothermia, hypotension, and resistant bradyarrhythmias. Risk factors include renal dysfunction, age 65 years and older, hypoxic states, excessive alcohol intake, and liver dysfunction. Lactic acidosis has been associated with metformin accumulation in plasma at levels generally exceeding 5 mcg/mL. The risk of metformin-associated lactic acidosis increases with the patient's age because patients 65 years and older have a greater likelihood of having hepatic, renal, or cardiac impairment. Renal function should be assessed more frequently in older adult patients. Several postmarketing cases of metformin-associated lactic acidosis occurred in the setting of acute congestive heart failure, especially when accompanied by hypoperfusion and hypoxemia; cardiovascular collapse (shock), acute myocardial infarction, sepsis, and other conditions associated with hypoxemia (e.g., severe anemia, asphyxia) have been associated with lactic acidosis and may cause prerenal azotemia. When such an event occurs, metformin should be discontinued. Dehydration (e.g., severe diarrhea or vomiting) may increase the risk for volume depletion, hypotension, and renal impairment; such patients may be at increased risk for lactic acidosis. Alcohol potentiates the effect of metformin on lactate metabolism; patients should be advised against excessive alcohol intake while receiving metformin. All patients treated with metformin should have renal function monitored regularly (at least annually or more frequently if necessary). If metformin-associated lactic acidosis is suspected, general supportive measures should be instituted promptly in a hospital setting, as well as immediate discontinuation of metformin. If lactic acidosis is diagnosed or strongly suspected, prompt hemodialysis is recommended to correct the acidosis and remove accumulated metformin. Patients and their families should be educated about the symptoms of lactic acidosis and, if these symptoms occur, they should be instructed to discontinue metformin and contact their health care provider.

Metformin decreases the liver uptake of lactate increasing lactate blood levels which may increase the risk of lactic acidosis, especially in at-risk patients. There have been reports of cases of metformin-associated lactic acidosis in patients with liver dysfunction. Metformin should generally be avoided in patients with evidence of hepatic disease.

Metformin is contraindicated in patients with acute or chronic metabolic acidosis (including diabetic ketoacidosis) with or without coma. Postmarketing cases of metformin-associated lactic acidosis have resulted in death, hypothermia, hypotension, and resistant bradyarrhythmias. Risk factors include renal dysfunction, age 65 years and older, hypoxic states, excessive alcohol intake, and liver dysfunction. Lactic acidosis has been associated with metformin accumulation in plasma at levels generally exceeding 5 mcg/mL. The risk of metformin-associated lactic acidosis increases with the patient's age because patients 65 years and older have a greater likelihood of having hepatic, renal, or cardiac impairment. Renal function should be assessed more frequently in older adult patients. Several postmarketing cases of metformin-associated lactic acidosis occurred in the setting of acute congestive heart failure, especially when accompanied by hypoperfusion and hypoxemia; cardiovascular collapse (shock), acute myocardial infarction, sepsis, and other conditions associated with hypoxemia (e.g., severe anemia, asphyxia) have been associated with lactic acidosis and may cause prerenal azotemia. When such an event occurs, metformin should be discontinued. Dehydration (e.g., severe diarrhea or vomiting) may increase the risk for volume depletion, hypotension, and renal impairment; such patients may be at increased risk for lactic acidosis. Alcohol potentiates the effect of metformin on lactate metabolism; patients should be advised against excessive alcohol intake while receiving metformin. All patients treated with metformin should have renal function monitored regularly (at least annually or more frequently if necessary). If metformin-associated lactic acidosis is suspected, general supportive measures should be instituted promptly in a hospital setting, as well as immediate discontinuation of metformin. If lactic acidosis is diagnosed or strongly suspected, prompt hemodialysis is recommended to correct the acidosis and remove accumulated metformin. Patients and their families should be educated about the symptoms of lactic acidosis and, if these symptoms occur, they should be instructed to discontinue metformin and contact their health care provider.

Metformin is contraindicated in patients with acute or chronic metabolic acidosis (including diabetic ketoacidosis) with or without coma. Postmarketing cases of metformin-associated lactic acidosis have resulted in death, hypothermia, hypotension, and resistant bradyarrhythmias. Risk factors include renal dysfunction, age 65 years and older, hypoxic states, excessive alcohol intake, and liver dysfunction. Lactic acidosis has been associated with metformin accumulation in plasma at levels generally exceeding 5 mcg/mL. The risk of metformin-associated lactic acidosis increases with the patient's age because patients 65 years and older have a greater likelihood of having hepatic, renal, or cardiac impairment. Renal function should be assessed more frequently in older adult patients. Several postmarketing cases of metformin-associated lactic acidosis occurred in the setting of acute congestive heart failure, especially when accompanied by hypoperfusion and hypoxemia; cardiovascular collapse (shock), acute myocardial infarction, sepsis, and other conditions associated with hypoxemia (e.g., severe anemia, asphyxia) have been associated with lactic acidosis and may cause prerenal azotemia. When such an event occurs, metformin should be discontinued. Dehydration (e.g., severe diarrhea or vomiting) may increase the risk for volume depletion, hypotension, and renal impairment; such patients may be at increased risk for lactic acidosis. Alcohol potentiates the effect of metformin on lactate metabolism; patients should be advised against excessive alcohol intake while receiving metformin. All patients treated with metformin should have renal function monitored regularly (at least annually or more frequently if necessary). If metformin-associated lactic acidosis is suspected, general supportive measures should be instituted promptly in a hospital setting, as well as immediate discontinuation of metformin. If lactic acidosis is diagnosed or strongly suspected, prompt hemodialysis is recommended to correct the acidosis and remove accumulated metformin. Patients and their families should be educated about the symptoms of lactic acidosis and, if these symptoms occur, they should be instructed to discontinue metformin and contact their health care provider.

The use of metformin is contraindicated in patients with severe renal dysfunction (estimated GFR [eGFR] less than 30 mL/min/1.73 m2). Metformin is substantially excreted by the kidney; the risk of metformin accumulation and lactic acidosis increases with the degree of renal dysfunction. Before starting metformin, an eGFR should be obtained. Initiation of metformin is not recommended in patients with eGFR between 30 and 45 mL/min/1.73 m2. An eGFR should be obtained at least annually in all patients; in those at risk of developing renal dysfunction (e.g., older adult patients), renal function should be assessed more frequently. In patients whose eGFR falls below 45 mL/min/1.73 m2, the benefit/risk of continuing therapy should be assessed. Postmarketing cases of metformin-associated lactic acidosis primarily occurred with significant renal dysfunction; metformin plasma levels generally exceeded 5 mcg/mL.

Metformin is contraindicated in patients with acute or chronic metabolic acidosis (including diabetic ketoacidosis) with or without coma. Postmarketing cases of metformin-associated lactic acidosis have resulted in death, hypothermia, hypotension, and resistant bradyarrhythmias. Risk factors include renal dysfunction, age 65 years and older, hypoxic states, excessive alcohol intake, and liver dysfunction. Lactic acidosis has been associated with metformin accumulation in plasma at levels generally exceeding 5 mcg/mL. The risk of metformin-associated lactic acidosis increases with the patient's age because patients 65 years and older have a greater likelihood of having hepatic, renal, or cardiac impairment. Renal function should be assessed more frequently in older adult patients. Several postmarketing cases of metformin-associated lactic acidosis occurred in the setting of acute congestive heart failure, especially when accompanied by hypoperfusion and hypoxemia; cardiovascular collapse (shock), acute myocardial infarction, sepsis, and other conditions associated with hypoxemia (e.g., severe anemia, asphyxia) have been associated with lactic acidosis and may cause prerenal azotemia. When such an event occurs, metformin should be discontinued. Dehydration (e.g., severe diarrhea or vomiting) may increase the risk for volume depletion, hypotension, and renal impairment; such patients may be at increased risk for lactic acidosis. Alcohol potentiates the effect of metformin on lactate metabolism; patients should be advised against excessive alcohol intake while receiving metformin. All patients treated with metformin should have renal function monitored regularly (at least annually or more frequently if necessary). If metformin-associated lactic acidosis is suspected, general supportive measures should be instituted promptly in a hospital setting, as well as immediate discontinuation of metformin. If lactic acidosis is diagnosed or strongly suspected, prompt hemodialysis is recommended to correct the acidosis and remove accumulated metformin. Patients and their families should be educated about the symptoms of lactic acidosis and, if these symptoms occur, they should be instructed to discontinue metformin and contact their health care provider.

Metformin is contraindicated in patients with acute or chronic metabolic acidosis (including diabetic ketoacidosis) with or without coma. Postmarketing cases of metformin-associated lactic acidosis have resulted in death, hypothermia, hypotension, and resistant bradyarrhythmias. Risk factors include renal dysfunction, age 65 years and older, hypoxic states, excessive alcohol intake, and liver dysfunction. Lactic acidosis has been associated with metformin accumulation in plasma at levels generally exceeding 5 mcg/mL. The risk of metformin-associated lactic acidosis increases with the patient's age because patients 65 years and older have a greater likelihood of having hepatic, renal, or cardiac impairment. Renal function should be assessed more frequently in older adult patients. Several postmarketing cases of metformin-associated lactic acidosis occurred in the setting of acute congestive heart failure, especially when accompanied by hypoperfusion and hypoxemia; cardiovascular collapse (shock), acute myocardial infarction, sepsis, and other conditions associated with hypoxemia (e.g., severe anemia, asphyxia) have been associated with lactic acidosis and may cause prerenal azotemia. When such an event occurs, metformin should be discontinued. Dehydration (e.g., severe diarrhea or vomiting) may increase the risk for volume depletion, hypotension, and renal impairment; such patients may be at increased risk for lactic acidosis. Alcohol potentiates the effect of metformin on lactate metabolism; patients should be advised against excessive alcohol intake while receiving metformin. All patients treated with metformin should have renal function monitored regularly (at least annually or more frequently if necessary). If metformin-associated lactic acidosis is suspected, general supportive measures should be instituted promptly in a hospital setting, as well as immediate discontinuation of metformin. If lactic acidosis is diagnosed or strongly suspected, prompt hemodialysis is recommended to correct the acidosis and remove accumulated metformin. Patients and their families should be educated about the symptoms of lactic acidosis and, if these symptoms occur, they should be instructed to discontinue metformin and contact their health care provider.

Hypoglycemia may commonly occur during treatment with insulin and/or oral hypoglycemic agents. Care should be taken in patients who may be particularly susceptible to the development of hypoglycemic episodes during the use of these drugs, including those who are debilitated or malnourished, those with defective counterregulatory mechanisms (e.g., autonomic neuropathy and adrenal or pituitary insufficiency), and those receiving beta-adrenergic blocking agents.

Metformin may interfere with vitamin B12 absorption from the B12-intrinsic factor complex. A decrease to subnormal levels of previously normal serum vitamin B12 levels was reported in about 7% of patients treated with metformin during clinical trials. Such decrease may be associated with anemia but appears to be rapidly reversible with metformin discontinuation or vitamin B12 supplementation. Certain patients (those with inadequate vitamin B12 or calcium intake or absorption) appear to be predisposed to developing subnormal levels of vitamin B12; caution may be warranted when metformin is administered to these patients. It is recommended to measure vitamin B12 every 2 to 3 years and hematologic parameters annually in patients on metformin. Any abnormalities should be managed.

Hypoglycemia may commonly occur during treatment with insulin and/or oral hypoglycemic agents. Care should be taken in patients who may be particularly susceptible to the development of hypoglycemic episodes during the use of these drugs, including those who are debilitated or malnourished, those with defective counterregulatory mechanisms (e.g., autonomic neuropathy and adrenal or pituitary insufficiency), and those receiving beta-adrenergic blocking agents.

Hypoglycemia may commonly occur during treatment with insulin and/or oral hypoglycemic agents. Care should be taken in patients who may be particularly susceptible to the development of hypoglycemic episodes during the use of these drugs, including those who are debilitated or malnourished, those with defective counterregulatory mechanisms (e.g., autonomic neuropathy and adrenal or pituitary insufficiency), and those receiving beta-adrenergic blocking agents.

Metformin may interfere with vitamin B12 absorption from the B12-intrinsic factor complex. A decrease to subnormal levels of previously normal serum vitamin B12 levels was reported in about 7% of patients treated with metformin during clinical trials. Such decrease may be associated with anemia but appears to be rapidly reversible with metformin discontinuation or vitamin B12 supplementation. Certain patients (those with inadequate vitamin B12 or calcium intake or absorption) appear to be predisposed to developing subnormal levels of vitamin B12; caution may be warranted when metformin is administered to these patients. It is recommended to measure vitamin B12 every 2 to 3 years and hematologic parameters annually in patients on metformin. Any abnormalities should be managed.

Acute hemolysis following administration of high doses of ascorbic acid in patients with glucose-6-phosphate deficiency (G6PD) has been reported. Ascorbic acid should be administered cautiously and dosages modified in patients with G6PD.

Ascorbic acid preparations contain sodium. The sodium content should be considered when used in patients with sodium restricted diets and conditions require sodium restriction, such as congestive heart failure, hypertension, and fluid retention.

Ascorbic acid preparations contain sodium. The sodium content should be considered when used in patients with sodium restricted diets and conditions require sodium restriction, such as congestive heart failure, hypertension, and fluid retention.

Hypoglycemia may commonly occur during treatment with insulin and/or oral hypoglycemic agents. Care should be taken in patients who may be particularly susceptible to the development of hypoglycemic episodes during the use of these drugs, including those who are debilitated or malnourished, those with defective counterregulatory mechanisms (e.g., autonomic neuropathy and adrenal or pituitary insufficiency), and those receiving beta-adrenergic blocking agents.

Large doses of ascorbic acid have lead to hyperoxaluria in 5% of patients. Ascorbic acid can acidify urine resulting in precipitation of urate, cystine, or oxalate stones. Ascorbic acid should be administered cautiously and dosages modified in patients predisposed to renal stones. Clinical monitoring of urinalysis for pH and crystal formation is recommended.

Hypoglycemia may commonly occur during treatment with insulin and/or oral hypoglycemic agents. Care should be taken in patients who may be particularly susceptible to the development of hypoglycemic episodes during the use of these drugs, including those who are debilitated or malnourished, those with defective counterregulatory mechanisms (e.g., autonomic neuropathy and adrenal or pituitary insufficiency), and those receiving beta-adrenergic blocking agents.

Ascorbic acid is removed by dialysis.