Special instructions and precautions
Risk of developing lactic acidosis
Metformin can cause a rare but very serious complication, lactic acidosis, especially if kidney function is impaired. The risk of developing lactic acidosis increases in the case of uncontrolled diabetes, serious infections, prolonged fasting, alcoholism, dehydration (see information below), liver failure and any pathology in which hypoxia occurs (for example, severe heart disease).
If you have any of these conditions, talk to your doctor before using metformin.
Stop taking metformin for a short time if you have a risk of dehydration (more body fluid loss than necessary), such as severe vomiting, diarrhea, fever, exposure to high temperatures, or insufficient fluid intake.
If you have any questions, consult your doctor,
If you develop symptoms of lactic acidosis, stop taking metformin and tell your doctor or go to your nearest hospital immediately, as lactic acidosis can lead to coma.
Symptoms of lactic acidosis:
- vomit
- abdominal pain
- muscle spasms
- general poor health, accompanied by severe fatigue
- labored breathing
- decreased body temperature and heart rate
Lactic acidosis requires emergency medical attention.
If you are having major surgery, you should stop taking metformin for the duration of surgery and for some time afterward.
Your doctor will advise you when to stop and restart treatment.
Metformin as monotherapy does not cause hypoglycemia (lowering blood glucose levels). However, when used simultaneously with other antidiabetic drugs (sulfonylurates, insulin, meglitinides), there is a risk of developing hypoglycemia.
If you experience symptoms of hypoglycemia, such as weakness, dizziness, increased sweating, rapid heartbeat, or problems with vision or concentration, you should immediately drink or eat something containing sugar.
Renal function should be closely monitored at least once a year during treatment with metformin, or more often if you are elderly or have worsening kidney function.
Drug interactions
If you need to have intravascular injection of iodinated contrast agents, such as for x-rays, you must stop taking metformin before or during the procedure. Your doctor will tell you when to stop or when to restart taking metformin.
Tell your doctor if you are taking, have recently taken or might take any other medicines. You may need to have your blood glucose levels and kidney function assessed more frequently, or your doctor may need to adjust your metformin dose.
It is especially important to note the following medications:
- medications that increase urine production (diuretics).
- medications that have analgesic and anti-inflammatory effects (NSAIDs and COX-2 inhibitors such as ibuprofen and celecoxib).
- certain medications to treat high blood pressure (ACE inhibitors and angiotensin II receptor antagonists).
- beta-2 adrenergic agonists such as salbutamol or terbutaline (drugs used to treat asthma).
- corticosteroids (used to treat various conditions such as severe skin inflammation or asthma).
- Medicines that may affect blood levels of metformin, especially if kidney function is impaired (eg, verapamil, rifampicin, cimetidine, dolutegravir, ranolazine, trimethoprim, vandetanib, isavuconazole, crizotinib, olaparib).
- other medicines used to treat diabetes mellitus
Metformin and alcohol
Avoid excessive drinking of alcohol while taking metformin as this may cause lactic acidosis (see Warnings and Precautions).
Pregnancy and breastfeeding
During pregnancy, you need insulin to treat diabetes.
Check with your doctor if you are pregnant, think you may be pregnant, or are planning to become pregnant before taking this drug as it may change your treatment.
It is not recommended to take metformin while breastfeeding.
Metformin long
The drug is taken orally. The tablets are swallowed whole, without chewing, with a sufficient amount of liquid, 1 time per day (once/day) during dinner.
The dose of Metformin Long is selected individually for each patient based on the results of determining blood glucose concentrations.
In patients with normal renal function (creatinine clearance ≥ 90 ml/min)
Monotherapy and combination therapy in combination with other hypoglycemic agents
— The drug Metformin Long at a dose of 850 mg — 2 tablets (1700 mg) 1 time per day.
— The drug Metformin Long at a dose of 1000 mg should be taken 1 time/day during dinner.
— The drug Metformin Long at a dose of 1000 mg is prescribed as maintenance therapy for patients taking metformin in the form of regular-release tablets at a dose of 1000 mg or 2000 mg. To switch to Metformin Long at a dose of 1000 mg, the daily dose of metformin should be equivalent to the daily dose of regular-release metformin.
— Patients taking metformin in the form of regular-release tablets at a dose exceeding 2000 mg are not recommended to switch to Metformin Long at a dose of 1000 mg.
- For patients not taking metformin, it is recommended to start with extended-release metformin at a dose of 500 mg or 850 mg 1 time / day with dinner. Every 10-15 days it is recommended to adjust the dose based on the results of determining the concentration of glucose in the blood. Slowly increasing the dose promotes better gastrointestinal tolerability.
- In case of switching from another hypoglycemic agent, dose selection is carried out as described above, starting with taking metformin extended-release drugs at a dose of 500 mg or 850 mg, with a possible subsequent transition to Metformin Long at a dose of 1000 mg.
Combination with insulin
To achieve better glycemic control, metformin and insulin can be used in combination therapy. Typically, extended-release metformin is started at a dose of 500 or 850 mg once a day with dinner, while the insulin dose is adjusted based on blood glucose results. Then it is possible to switch to Metformin Long at a dose of 1000 mg.
Daily dose
The maximum recommended dose of Metformin Long at a dose of 850 mg is 3 tablets once a day (2550 mg), at a dose of 1000 mg - 2 tablets per day (2000 mg).
If, when taking the maximum recommended dose once a day, it is not possible to achieve adequate glycemic control, the maximum dose can be divided into two doses: one Metformin Long tablet at a dose of 1000 mg - during breakfast and one Metformin Long tablet at a dose of 1000 mg - during dinner. If adequate glycemic control is not achieved in this case, a switch to regular-release metformin preparations with a maximum daily dose of 3000 mg is possible.
Use of the drug in special clinical groups of patients
Patients with kidney failure
Metformin can be used in patients with renal failure with a creatinine clearance of 30-59 ml/min only in the absence of conditions/risk factors that may increase the risk of developing lactic acidosis.
The initial dose of extended-release metformin is 500 mg or 850 mg once a day.
Renal function (KF) should be assessed before initiating metformin therapy and then at least once a year. In patients at increased risk of progression of renal failure and in the elderly, renal function should be monitored more frequently (every 3-6 months).
In patients with CC 45-59 ml/min, it is necessary to determine CC every 3-6 months; with CC 30-44 ml/min - every 3 months.
If CC is below 30 ml/min, the drug should be stopped immediately.
| Creatinine clearance (CC) (ml/min) | Total maximum daily dose | additional information |
| 60-89 | 2000 mg | Due to decreased renal function, a reduction in the dose of metformin should be considered. |
| 45-59 | 2000 mg | Before starting metformin therapy, factors that increase the risk of developing lactic acidosis should be studied (see section "Special Instructions"). The initial dose is half the maximum daily dose. |
| 30-44 | 1000 mg | |
| <30 | Taking metformin is contraindicated. |
Elderly patients
In elderly patients, the dose of metformin is adjusted based on an assessment of renal function, which should be carried out regularly (see section "Special Instructions").
Children and teenagers under 18 years of age
The use of the drug is contraindicated in children and adolescents under the age of 18 (due to the lack of clinical data on effectiveness and safety).
Duration of treatment
Metformin Long should be taken daily, without interruption. If treatment is stopped, the patient must inform the doctor.
Missing a dose
If a dose is missed, the patient should take the next dose at the usual time. You should not take a double dose of Metformin Long.
Metformin, 60 pcs., 1000 mg, film-coated tablets
Lactic acidosis
Lactic acidosis is a rare but serious (high mortality unless promptly treated) complication that may occur due to accumulation of metformin. Cases of lactic acidosis when taking metformin occurred mainly in patients with diabetes mellitus with severe renal failure.
Other associated risk factors should be taken into account, such as decompensated diabetes mellitus, ketosis, prolonged fasting, alcoholism, liver failure and any condition associated with severe hypoxia. This may help reduce the incidence of lactic acidosis.
The risk of developing lactic acidosis should be taken into account when nonspecific signs appear, such as muscle cramps accompanied by dyspeptic symptoms, abdominal pain and severe asthenia. Lactic acidosis is characterized by acidotic shortness of breath, abdominal pain and hypothermia followed by coma.
Diagnostic laboratory parameters are a decrease in blood pH (less than 7.25), lactate content in the blood plasma over 5 mmol/l, increased anion gap and lactate/pyruvate ratio.
If metabolic acidosis is suspected, stop taking the drug and consult a doctor immediately.
Surgical operations
The use of metformin should be discontinued 48 hours before elective surgery and can be continued no earlier than 48 hours after, provided that renal function was found to be normal during the examination.
Metformin should be replaced with another hypoglycemic drug (for example, insulin) 48 hours before an x-ray examination with intravenous contrast agents and continued for another 48 hours after this examination.
Kidney function
Since metformin is excreted by the kidneys, before starting treatment and regularly thereafter, it is necessary to determine CC: at least once a year in patients with normal renal function, and 2-4 times a year in elderly patients, as well as in patients with CC at the lower limit norms.
Particular caution should be exercised in case of possible impairment of renal function in elderly patients, with simultaneous use of antihypertensive drugs, diuretics or non-steroidal anti-inflammatory drugs.
Use in children and adolescents
The diagnosis of type 2 diabetes mellitus must be confirmed before starting treatment with metformin.
In clinical studies lasting 1 year, metformin was shown to have no effect on growth and puberty. However, due to the lack of long-term data, careful monitoring of the subsequent effects of metformin on these parameters in children, especially during puberty, is recommended. The most careful monitoring is necessary in children aged 10–12 years.
Other Precautions
Patients are advised to continue to follow a diet with even carbohydrate intake throughout the day. Overweight patients are recommended to continue to follow a hypocaloric diet (but not less than 1000 kcal/day).
It is recommended that routine laboratory tests be performed regularly to monitor diabetes mellitus.
It is not recommended to prescribe the drug if there is a risk of dehydration.
Metformin does not cause hypoglycemia when used alone, but caution is recommended when used in combination with insulin or other hypoglycemic agents (for example, sulfonylureas, repaglinide). When combined treatment requires careful monitoring of blood glucose concentrations.
Impact on the ability to drive vehicles and machinery
Monotherapy with the drug does not cause hypoglycemia and therefore does not affect the ability to drive vehicles and machines. Patients should be warned about the risk of developing hypoglycemia when using metformin in combination with other hypoglycemic drugs (sulfonylurea derivatives, insulin, repaglinide, etc.), which impair the ability to drive vehicles and engage in other potentially hazardous activities that require increased alertness and quick response. psychomotor reactions.
