What are the side effects of metformin HCl?

Metformin HCl may cause side effects. These could include:

  • muscle pain
  • weakness
  • mild nausea
  • vomiting
  • gas
  • headache
  • diarrhea
  • stomach pain

Some side effects are more serious. These include:

  • shortness of breath
  • fever
  • chills
  • body aches
  • flu symptoms
  • rapid weight gain
  • swelling

Some people who take metformin HCl can develop lactic acidosis, a possibly life-threatening medical condition. Symptoms are:

  • slow heart rate
  • muscle pain
  • fainting
  • weakness
  • increasing sleepiness
  • cold feeling
  • light-headedness
  • stomach pain

If you experience any serious side effects of metformin HCl, call your doctor immediately. If you develop signs of lactic acidosis, seek emergency medical care. It is possible that your blood sugar could drop to a dangerously low level while taking metformin HCl. Signs of this are:

  • confusion
  • drowsiness
  • weakness
  • hunger
  • headache
  • sweating
  • coma
  • fainting
  • seizure
  • fast heartbeat

You should make sure that you always have immediate access to a sugar source in case you develop any of these symptoms. It is also possible to experience an allergic reaction to metformin HCl. If you develop symptoms of an allergic reaction like difficulty breathing, hives, or swelling of the lips, tongue, face, or throat, seek emergency medical attention.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.