Metformin contraindications and warnings


The following provides information on contraindications in the use of metformin in general, in pregnancy, breastfeeding and children. Please note that the contraindications may vary depending on the dosage form of a drug (eg tablet, syringe, ointment).

When should Metformin not be used?

Metformin must not be used with

  • Hypersensitivity to the active substance
  • Metabolic disorders such as diabetic ketoacidosis or diabetic prokoma
  • Renal failure or renal impairment (creatinine clearance below 30 milliliters / minute)
  • acute conditions that can lead to impaired kidney function such as dehydration, severe infections and shock
  • Administration of iodinated contrast media into the vein
  • Lack of oxygen supply to the tissue due to cardiac or pulmonary dysfunction, recent heart attack or shock
  • liver dysfunction
  • acute alcohol poisoning or alcoholism.

Metformin therapy should be administered only under special medical supervision at

  • elderly patients with possibly impaired renal function, patients with a tendency to renal dysfunction, or taking medicines that alter kidney function: antihypertensive, dehydrating and non-steroidal anti-inflammatory drugs
  • Risk of lactate acidosis such as fasting, increased blood ketone concentration, poorly controlled diabetes.

Before starting treatment, and thereafter, the physician should perform regular blood creatinine concentration checks. At normal renal function at least annually; in elderly patients and when the blood creatinine level is at the upper limit of the normal range, at least two to four times a year.

In general, regular medical laboratory examinations should be carried out during therapy with the active substance. A blood sugar lowering diet should be continued, paying attention to adequate carbohydrate distribution. Obese people should continue to diet for weight loss.

What should you watch out for during pregnancy and lactation?

Basically, metformin should not be used during pregnancy. The possible blood sugar fluctuations are too dangerous for the unborn child. Instead, diabetic patients who are pregnant or would like to become pregnant should be treated with insulin. With insulins a balanced blood sugar adjustment to normal values is more easily possible. This also reduces the risk of damaging unborn children due to blood sugar fluctuations.

Metformin should not be used during breast-feeding. If the doctor considers maternal treatment to be unavoidable with metformin, it must be stopped.

What should be considered in children?

Few children between the ages of 10 and 12 were included in the clinical trials of children and adolescents. The efficacy and safety of metformin did not differ from those found in older children in children under 12 years of age. Nevertheless, special care is recommended to physicians in the prescription of metformin for children between ten and twelve years old.

Warnings and Precautions

  • Alcohol intake must be restricted, if not completely avoided, during treatment with metformin.
  • Regular medical check-up of renal function is necessary during therapy with the drug.
  • Nausea, vomiting and abdominal pain may indicate lactic acidosis. In such cases the doctor should be consulted.
  • The drug is not suitable for children under the age of ten
  • At the beginning of therapy or in case of improper use of the active substance, road traffic or machinery may be affected by low blood glucose.

Sometimes medications release allergic reactions.
If you notice any signs of allergic reaction, tell your doctor or pharmacist immediately.