Description of Metformin Hydrochloride TabletsPlease read the instructions carefully and use under the guidance of your physician
[Drug Name].
Generic Name: Metformin Hydrochloride Tablets
English name: Metformin Hydrochloride Tablets
Hanyu Pinyin: Yansuan Erjiashuanggua Pian
[Ingredients
The main ingredient of this product is metformin hydrochloride.
Chemical name: 1,1-dimethylbiguanide hydrochloride.
Chemical structure formula.
Molecular Formula: C4H11N5-HCl
Molecular weight: 165.63
[Properties]This product is a film-coated tablet, which appears white after removing the coating.
[Indications
This product is preferred for type 2 diabetes where diet and physical exercise alone have failed to control blood glucose.
For adults, it can be used as monotherapy or in combination with a sulfonylurea or insulin.
For children and adolescents 10 years of age and older, this product can be used as monotherapy or in combination with insulin.
[Specification]0.25g
[Dosage]
Normal renal function (eGFR ≥ 90mL/min/1.73m2):
Monotherapy and in combination with sulfonylureas
Orally, adults and children start with 0.25g twice to three times a day for 10-15 days and then gradually increase the dosage according to the efficacy, The maximum recommended dose is 2 g per day. taken with meals to reduce gastrointestinal reactions.
Co-administration with sulfonylureas
Patients who do not respond after several weeks on the maximum recommended dose of this product should be considered for gradual addition of a sulfonylurea oral hypoglycemic agent while maintaining maximum dose therapy, unless the patient already has primary or secondary failure to sulfonylureas. Only clinical and pharmacokinetic data on the interaction between metformin and glibenclamide (euglycemia) are available.
Satisfactory glycemic control can be achieved with the combination of this product and a sulfonylurea by adjusting the dose of both drugs. The risk of hypoglycemia with sulfonylureas persists and even increases with combination therapy with this drug and should be appropriately prevented.
If patients do not have satisfactory glycemic control after 1 to 3 months of treatment with the maximum dose of this drug in combination with the maximum dose of oral sulfonylurea, consider a change in therapy, including treatment with this drug in combination with insulin or insulin alone.
Co-administration with insulin
The dose of insulin can be maintained when adding this product is started. The starting dose of this product for insulin-treated patients should be 0.5 g once/day. If the patient does not respond adequately, increase by 0.5g after 1 week, and thereafter by 0.5g weekly until satisfactory glycemic control is achieved. The recommended maximum daily dose is 2 g. When the fasting blood glucose of a patient using this product in combination with insulin drops below 120 mg/dL, it is recommended that the insulin dose be reduced by 10% to 25%. Individualized adjustments should continue to be made or as prescribed by the physician based on the response to the lowering of blood glucose.
Dose adjustment in adults with impaired renal function
EGFR ≥60mL/min/1.73m2No dose adjustment is required, eGFR 45-59mL/min/1.73m2Decrease, eGFR<45mL/min/1.73m2Discontinue.
[Adverse Reactions
According to foreign literature.
At initial treatment, the most common adverse reactions include nausea, vomiting, diarrhea, abdominal pain, and loss of appetite, which usually resolve on their own in most patients. The following adverse reactions may occur while taking metformin hydrochloride tablets.
The frequency of adverse reactions is defined as follows: very common (≥10%); common (1% to 10% with 1%) ,occasional (0.1% to 1% with 0.1%), rare (0.01% to 0.1% with 0.01%), and very rare (<0.01%). Within each frequency group, adverse reactions were listed in decreasing order of severity.
Metabolic and nutritional disorders.
Very rare.
Lactic acidosis (see [Precautions])
Long-term metformin administration may decrease vitamin B12 absorption. This cause should be considered if the patient develops megaloblastic anemia.
Nervous system abnormalities.
Common.
Taste disorders
Gastrointestinal abnormalities.
Very common.
Gastrointestinal abnormalities such as nausea, vomiting, diarrhea, abdominal pain, and loss of appetite. Most of these adverse reactions occur at the start of treatment and usually resolve on their own in most patients. Slowly increasing the dose may improve gastrointestinal tolerability.
Abnormal hepatobiliary function.
Very rare.
Individual cases of abnormal liver function tests or hepatitis have been reported to return to normal after discontinuation of metformin.
Dermal and subcutaneous tissue abnormalities.
Very rare.
Dermal reactions such as erythema, pruritus, and urticaria.
Other possible adverse reactions include: bloating, fatigue, indigestion, abdominal discomfort and headache, abnormal stools, constipation, bloating, hypoglycemia, myalgia, dizziness, lightheadedness, abnormal nails, rash, increased sweating, chest discomfort, chills, flu symptoms, hot flashes, palpitations, and weight loss.
Children
Adverse events and their severity were similar to those in adults in published data, post-marketing data, and in a one-year controlled clinical study in a limited number of children aged 10-16 years.
[Contraindicated].
Severe renal failure (eGFR<45mL/min/1.73m2).
Acute conditions that may affect renal function, e.g., dehydration, severe infection, shock.
Diseases that can cause tissue hypoxia (especially acute conditions or worsening of chronic conditions), such as decompensated heart failure, respiratory failure, recent onset myocardial infarction, and shock.
Severe infections and trauma, major surgical procedures with clinical hypotension and hypoxia.
Known hypersensitivity to metformin hydrochloride and any of the components of this product.
Any acute metabolic acidosis, including lactic acidosis, diabetic ketoacidosis.
The prodromal phase of diabetic coma.
hepatic insufficiency, acute alcohol intoxication, alcohol abuse.
Vitamin B12, folic acid deficiency uncorrected
[Caution].
Warning
Lactic acidosis.
Lactic acidosis is a very rare but serious metabolic complication that can be induced by accumulation of metformin in the body and is commonly seen in patients with acute deterioration of renal function, cardiopulmonary disease, or sepsis.
Patients who develop dehydration (severe diarrhea or vomiting, fever, or decreased fluid intake) should temporarily discontinue metformin and inform their physician.
In patients taking metformin, be alert to the use of medications that can cause acute impairment of renal function [including antihypertensives, diuretics, and nonsteroidal anti-inflammatory drugs (NSAIDs)]. Risk factors for lactic acidosis also include excessive alcohol consumption, hepatic insufficiency, poorly controlled diabetes mellitus, ketosis, prolonged fasting, and any disease that may cause hypoxia, as well as concomitant use of medications that may cause lactic acidosis.
Patients and/or caregivers should be informed of the risk of lactic acidosis. Lactic acidosis is characterized by acidotic dyspnea, abdominal pain, muscle cramps, debilitation, and decreased body temperature leading to coma. At the first sign of suspicion, patients should discontinue metformin and promptly inform their physician. Laboratory test abnormalities include decreased pH (<7.35), plasma lactate levels above 5 mmol/L and anion gap, and elevated lactate/pyruvate ratio.
General considerations
Lactic acidosis is an acute condition that must be treated in the hospital. Patients with lactic acidosis on this product should be immediately discontinued and promptly tested to support the diagnosis.
Chronic kidney disease is a common complication of diabetes, and once diabetes is diagnosed, renal function should be routinely checked. Metformin is excreted through the kidneys, and as the degree of renal impairment increases, the risk of metformin accumulation and the development of lactic acidosis increases. Renal function should be checked before starting treatment and at least annually after treatment.
This product is contraindicated in patients with eGFR<45mL/min/1.73m2. This product should be temporarily discontinued in patients presenting with acute conditions affecting renal function such as dehydration, severe infection, or shock. (See [Contraindications])
Cardiac function:
Patients with heart failure are at higher risk for hypoxia and renal insufficiency. Patients with stable chronic heart failure can take metformin with regular checks of cardiac and renal function.
Metformin is contraindicated in patients with acute and unstable heart failure (see [Contraindications]).
Iodinated contrast use:
Intravascular injection of iodinated contrast media may lead to contrast nephropathy, which may cause metformin accumulation and an increased risk of lactic acidosis. Therefore, patients who are scheduled for this type of test must stop taking metformin before or at the time of the test and resume the drug at least 48 hours after the test is completed and only if renal function is stable on reexamination.
Surgery:
Metformin must be discontinued when undergoing surgery with conventional, spinal, or epidural anesthesia. Treatment should not be restarted until at least 48 hours after surgery or after resumption of feeding and assessment of stable renal function.
Other Precautions:
All patients should continue to rationalize their dietary intake of carbohydrates. Overweight patients should continue a calorie-restricted diet.
Routine laboratory tests should be performed regularly to monitor diabetes.
Vitamin B12 levels – Some patients (those with inadequate intake or absorption of vitamin B12 and calcium) may be more susceptible to decreased vitamin B12 levels. It is beneficial for such patients to have their serum vitamin B12 levels measured every 2-3 years.
Hypoglycemia – Patients receiving this product alone do not normally develop hypoglycemia, but should be alert for hypoglycemia when combined with insulin or other glucose-lowering drugs (eg, sulfonylureas or glinides). Hypoglycemia is more likely to occur in elderly, debilitated, or malnourished patients, as well as in patients with hypoadrenal and pituitary gland function and alcoholism.
Children – A diagnosis of type 2 diabetes should be confirmed before starting metformin therapy. According to the foreign literature, a 1-year controlled clinical study has not found effects of metformin on growth and puberty in children, but no long-term data are available in this regard. Therefore, children treated with metformin, especially prepubertal children, should be carefully followed to determine the effect of metformin on these parameters.
Children 10 to 12 years of age
According to the foreign literature, a clinically controlled study in children and adolescents included only 15 children aged 10-12 years. Although the efficacy and safety data for metformin in these children did not differ from those in older children and adolescents, special caution should be exercised when prescribing metformin for children aged 10-12 years.
[For pregnant and lactating women
Pregnant women
For patients who are planning to become pregnant or are already pregnant, metformin is not recommended, but insulin may be used to maintain blood glucose levels as close to normal as possible, thereby reducing the risk of fetal malformations.
Lactating women
Metformin can be excreted through breast milk. Breastfeeding is not recommended during metformin therapy.
[Pediatric Dosage].
This product may be used as monotherapy or in combination with insulin in children and adolescents 10 years of age and older. See [Dosage].
This product is not recommended for use in children under 10 years of age.
Because elderly patients may have decreased renal function, renal function should be checked regularly and the dose of metformin should be adjusted according to renal function.
[Effect on ability to drive and operate machinery
Patients treated with metformin alone do not normally develop hypoglycemia, so metformin has no effect on the ability to drive or operate machinery. However, the combination with insulin or other glucose-lowering drugs (e.g., sulfonylureas) should be used with caution for hypoglycemia.
[Drug Interactions
1. No changes in pharmacokinetic parameters of metformin were observed with the single-dose combination of metformin and glibenclamide.
2. The combination of metformin and furosemide (tachyphylaxis) resulted in an increase in the AUC of metformin but no change in renal clearance, while the Cmax and AUC of furosemide decreased, with a shortened terminal half-life and no change in renal clearance.
3. Cationic drugs that are secreted via the renal tubule (eg, aminoclopramide, digoxin, morphine, procainamide, quinidine, quinine, ranitidine, aminoglutethimide, meperidine, and vancomycin) may theoretically compete with metformin for renal tubular transport and interact with each other, so close monitoring and dose adjustment of this product and/or interacting drugs is recommended.
4. The plasma and whole blood AUC of metformin increased when metformin was combined with cimetidine, but no changes in the clearance half-life of metformin were seen when the two drugs were combined alone. No changes in the pharmacokinetics of cimetidine were seen.
5. Monitor blood glucose closely if certain drugs that can cause elevated blood glucose, such as thiazides or other diuretics, glucocorticoids, phenothiazines, thyroid preparations, estrogens, oral contraceptives, phenytoin, nicotinic acid, sympathomimetics, calcium channel blockers, and isoniazid, are taken concomitantly, and watch closely for hypoglycemia after these drugs are discontinued.
6. Metformin is not bound to plasma proteins. Therefore drugs that are highly protein bound, such as salicylates, aminoglycosides, chloramphenicol, and probenecid, are less likely to interact with sulfonylureas than with serum proteins, which are primarily bound to serum proteins.
7. With the exception of chlorosulfonylurea, a conversion period is usually not required when patients switch from other oral hypoglycemic agents to treatment with this product. Patients taking chlorosulfonylurea should be closely monitored during the first 2 weeks of switching to this product because chlorosulfonylurea has a long retention period in the body, which can lead to drug overdose and hypoglycemia.
8. In healthy individuals on a single-dose combination of nifedipine and metformin, the peak plasma concentration and area under the plasma concentration time curve of metformin increased by 20% and 9%, respectively, and urinary excretion increased, with no effect on Tmax or half-life.
9. Metformin has a tendency to increase the anticoagulant properties of warfarin.
10. Resinous drugs in combination with this product may decrease metformin absorption.
[Drug overdose].
According to the foreign literature, lactic acidosis occurs in this setting even though metformin doses up to 85 g have not been associated with hypoglycemia. In good hemodynamic conditions metformin can be cleared by dialysis at a rate of 170 mL/min. Therefore, in patients with suspected metformin overdose, hemodialysis can remove the accumulated drug.
[Pharmacologic Toxicology
Pharmacology
Metformin reduces hepatic gluconeogenesis, inhibits intestinal absorption of glucose, and increases glucose uptake and utilization by peripheral tissues, which may improve insulin sensitivity by increasing peripheral glucose uptake and utilization.
Toxicological studies
Genotoxicity.
The results of the Ames test, mouse lymphocyte gene mutation test, human lymphocyte chromosome aberration test, and mouse micronucleus test were all negative.
Reproductive toxicity.
No effects on fertility were seen in male and female rats given metformin hydrochloride at doses up to 600 mg/kg/day (equivalent to 3 times the maximum recommended daily human clinical dose based on body surface area). No teratogenic effects were observed in rats and rabbits given metformin hydrochloride at doses up to 600 mg/kg/day (2 and 6 times the maximum recommended daily dose for humans based on body surface area). Results in lactating rats showed that metformin hydrochloride can be secreted into breast milk and can reach levels in plasma.
Carcinogenicity.
No evidence of carcinogenic effects of metformin was found in male and female mice given metformin 900 mg/kg/day for 104 weeks in rats and metformin 1500 mg/kg/day for 91 weeks in a carcinogenicity study in mice (these doses are equivalent to 4 times the maximum recommended clinical daily dose of metformin of 2000 mg on a body surface area basis). Metformin was also not found to be carcinogenic in male rats, but there was an increase in the development of benign interstitial uterine polyps in female rats at 900 mg/kg/day.
[Pharmacokinetics] According to foreign literature.
Absorption
After oral administration of metformin hydrochloride, blood concentrations peak (Cmax) after approximately 2.5 hours (Tmax). In a healthy population, the absolute bioavailability of oral metformin hydrochloride tablets is approximately 50-60%.
Eating reduces the extent and slightly slows the rate of absorption of the drug. A 40% reduction in peak blood concentrations and a 25% reduction in the area under the concentration curve (AUC) were observed with oral metformin hydrochloride tablets after eating.
Distribution
Metformin is barely bound to plasma proteins. Metformin partially enters the red blood cells. Peak metformin whole blood concentrations are lower than peak plasma concentrations, but occur at approximately the same time. Erythrocytes are probably the second distribution compartment for metformin, with a mean volume of distribution (Vd) of approximately 1.12 L/kg.
Metabolism
Metformin is excreted from the urine as a prototype. No relevant metabolites have been detected in humans.
Excretion
The renal clearance of metformin>400 mL/min suggests that glomerular filtration and renal tubular secretion are the routes of metformin excretion. After oral administration, the terminal plasma clearance half-life of metformin is approximately 3.6 hours. In renal insufficiency, renal clearance decreases with creatinine clearance, so the clearance half-life of metformin is prolonged, resulting in an increase in plasma metformin concentration.
Characterization in special populations
Renal insufficiency
There are few data on treatment in patients with moderate renal insufficiency and there are no reliable estimates of systemic exposure to metformin in these populations compared with patients with normal renal function. Therefore, clinical efficacy/tolerability should be considered for dose adjustment.
Children
According to foreign literature.
Single-dose study: pediatric patients receiving a single oral dose of metformin hydrochloride tablets 0.5 g showed a pharmacokinetic profile similar to that of healthy adults.
Multiple-dose study: data from only one study. Pediatric patients taking metformin hydrochloride tablets 0.5 g orally twice a day for 7 days had approximately 33% and 40% lower peak blood levels and systemic exposure (AUC0-t), respectively, compared with adult diabetic patients taking the same dose for 14 days of treatment. Clinical relevance is limited because the drug dose is titrated according to individual blood glucose levels.
[Storage]Seal and store.
[Packaging]Packaged in aluminum and plastic. 12 tablets/plate´ 10 plates/box; 6 tablets/plate´ 10 plates/box; 10 tablets/plate´ 10 plates/box. plate/box; 10 tablets/plate´10 plates/box
[Expiration date]12 months
[Executive Standard
[Approval number]State Drug Certificate H13021647
[Manufacturer
Company name: Hebei Tiancheng Pharmaceutical Co.
Production Address: No. 18, Jinguang Street, Cangzhou Economic and Technological Development Zone
Postal Code: 061000
Phone number: 0317-7883088
Fax number: 0317-7883077
Website: http://www.hbtcyy.com/