Metformin is a widely prescribed oral medication, generally considered the first-line treatment for managing blood sugar levels in people with Type 2 Diabetes. This drug works primarily by decreasing the amount of glucose produced by the liver and improving the body’s sensitivity to insulin. While Metformin is safe and effective when taken as prescribed, an acute accidental overdose represents a serious medical emergency that disrupts normal metabolic function. A suspected overdose requires immediate intervention and professional medical attention due to the potentially life-threatening risks.
Immediate and Common Physical Symptoms
Initial symptoms following an acute ingestion of excessive Metformin often manifest as severe gastrointestinal distress shortly after the drug is absorbed. The sudden high concentration of the drug leads to pronounced nausea, forceful vomiting, and significant diarrhea. These severe gastrointestinal reactions are accompanied by intense abdominal pain and a general feeling of being unwell or lethargic.
A less common immediate effect of an overdose is acute hypoglycemia, or dangerously low blood sugar, especially if the person is also taking other diabetes medications. Symptoms of low blood sugar include excessive sweating, confusion, dizziness, or a rapid, pounding heartbeat. Though Metformin does not typically cause hypoglycemia on its own, its effects combined with the acute stress of an overdose can lead to swift changes in blood glucose.
Recognizing the Signs of Lactic Acidosis
The most significant danger associated with a Metformin overdose is the development of Metformin-Associated Lactic Acidosis (MALA), a rare but potentially fatal condition. Metformin toxicity interferes with cellular respiration by inhibiting a process in the mitochondria. This disruption impairs the liver’s ability to clear lactate from the blood, causing a rapid and dangerous buildup of lactic acid.
Unlike common gastrointestinal upset, MALA presents with a distinct set of systemic symptoms reflecting severe metabolic failure. These signs include profound weakness and fatigue, unusual muscle pain or cramping (myalgia), and severe drowsiness that can progress to an altered mental state. The body attempts to compensate for the acid buildup by breathing rapidly and shallowly, a distinctive pattern known as hyperpnoea.
Other serious indicators of MALA are a sudden drop in body temperature (hypothermia) and a slow heart rate (bradycardia). The condition is characterized by a dangerously low blood pH level and extremely high lactate concentrations in the blood. While MALA is rare in patients taking therapeutic doses, the risk is significantly heightened in an acute overdose setting, even in individuals with normal kidney function.
Urgent Steps Following Accidental Overdose
The immediate priority following the discovery of a Metformin overdose is to secure professional medical assistance without delay. Call your local emergency services, such as 911, or the national Poison Control Center hotline immediately. These professionals can provide life-saving guidance while emergency medical help is on the way.
When making the call, be ready to provide specific information paramount for guiding the emergency response. Clearly state the exact name of the medication, the estimated amount of Metformin ingested, and the approximate time the overdose occurred. Provide the patient’s age and weight, as well as a list of any other medications, supplements, or substances they may have taken. Do not attempt to induce vomiting or give the person anything to eat or drink unless explicitly instructed by a medical professional.
Professional Medical Intervention and Recovery
Upon arrival at a medical facility, intervention for Metformin overdose focuses on stabilization and aggressive treatment of developing metabolic acidosis. Hospital staff immediately begin intensive monitoring of the patient’s vital signs and acid-base balance, including frequent blood gas and lactate level checks. Intravenous fluids are administered to help flush the Metformin from the system and correct associated dehydration.
If severe lactic acidosis is present, a solution of sodium bicarbonate may be given intravenously to neutralize the dangerous buildup of acid in the blood. The definitive treatment for a severe Metformin overdose is hemodialysis, a process where the patient’s blood is filtered through an external machine. Hemodialysis is effective because Metformin has a low molecular weight and does not bind extensively to proteins, allowing rapid removal of both the drug and the excess lactic acid. Once the acid-base balance is restored and the drug is cleared, the outlook for recovery is positive, though prolonged monitoring may be necessary.