Metformin Hydrochloride: Comprehensive Information

Metformin Hydrochloride is a widely prescribed oral antidiabetic drug belonging to the biguanide class. It is primarily used to manage type 2 diabetes mellitus.

Composition and Forms

The active pharmaceutical ingredient is Metformin Hydrochloride. It is typically available in immediate-release (IR) and extended-release (ER) tablet formulations. Common strengths include 500 mg, 850 mg, and 1000 mg.

Indications

Metformin Hydrochloride is indicated for:

• Management of type 2 diabetes mellitus in adults, as an adjunct to diet and exercise.
• It may be used as a first-line treatment or in combination with other antidiabetic agents such as sulfonylureas, insulin, or thiazolidinediones.
• Management of polycystic ovary syndrome (PCOS) in some regions, to improve hormonal balance and ovulation.

Mechanism of Action

Metformin works through several mechanisms to lower blood glucose levels:

• Decreases hepatic glucose production: It inhibits gluconeogenesis (the production of glucose by the liver).
• Increases insulin sensitivity: It improves the body's response to insulin, allowing cells to take up glucose more effectively.
• Reduces intestinal glucose absorption: It slightly decreases the amount of glucose absorbed from the digestive tract.

Unlike some other diabetes medications, Metformin does not stimulate insulin secretion, thus it generally does not cause hypoglycemia (low blood sugar) when used alone.

Safety Profile

Potential Benefits:

• Effective in lowering HbA1c levels.
• Associated with weight neutrality or modest weight loss.
• Lower risk of hypoglycemia compared to other oral hypoglycemic agents.
• Potential cardiovascular benefits in some patient populations.

Common Side Effects:

• Gastrointestinal disturbances are the most frequent, including nausea, vomiting, diarrhea, abdominal pain, and loss of appetite. These often improve over time or with dose adjustment.
• Metallic taste in the mouth.

Rare but Serious Side Effects:

• Lactic Acidosis: A rare but serious metabolic complication, characterized by an accumulation of lactic acid in the blood. Risk factors include impaired kidney function, liver disease, heart failure, and excessive alcohol intake. Symptoms may include muscle pain, difficulty breathing, abdominal discomfort, and fatigue.

Contraindications:

• Severe renal impairment (eGFR < 30 mL/min/1.73m²).
• Acute or chronic metabolic acidosis, including diabetic ketoacidosis.
• Hypersensitivity to Metformin Hydrochloride.
• Conditions that may predispose to renal impairment, such as dehydration, severe infection, shock, and the intravenous administration of iodinated contrast media.

Warnings:

• Patients with impaired renal function require careful monitoring.
• Discontinuation of Metformin is recommended temporarily prior to or at the time of intravascular iodinated contrast imaging procedures and for any condition that may compromise renal function.
• Alcohol intake should be limited due to the increased risk of lactic acidosis.

Dosage Table

Frequently Asked Questions

1. How long does it take for Metformin to work?

Metformin generally starts to lower blood sugar levels within a few days, but it can take a few weeks to see the full effects on your blood glucose and HbA1c levels. Consistent adherence to medication, diet, and exercise is crucial for optimal results.

2. Can I drink alcohol while taking Metformin?

It is strongly advised to limit or avoid alcohol consumption while taking Metformin. Alcohol, especially in large amounts, significantly increases the risk of a rare but serious side effect called lactic acidosis. If you choose to drink, do so in moderation and consult your doctor.

3. What should I do if I miss a dose of Metformin?

If you miss a dose of immediate-release Metformin, take it as soon as you remember, unless it is almost time for your next dose. In that case, skip the missed dose and continue with your regular dosing schedule. Do not take a double dose. For extended-release tablets, take the missed dose as soon as you remember, but do not take it if it is already time for your next scheduled dose. Consult your doctor or pharmacist if you are unsure.

4. Are there any foods I should avoid while taking Metformin?

While Metformin itself does not require strict dietary restrictions, it works best when combined with a healthy, balanced diet low in refined sugars and high in fiber. Some individuals experience gastrointestinal side effects that may be reduced by avoiding very fatty or spicy foods. It's important to follow the dietary recommendations provided by your healthcare provider.

5. What are the sigNs of lactic acidosis?

Signs of lactic acidosis are serious and require immediate medical attention. They include unusual muscle pain, difficulty breathing, unusual sleepiness, stomach pain, feeling cold, dizziness, or a slow or irregular heartbeat. If you experience any of these symptoms, stop taking Metformin and seek emergency medical help immediately.