Metformin vs. Victoza

• Metformin and Victoza (liraglutide) are used for treating type 2 diabetes.
• Metformin is also used to treat polycystic ovaries and weight gain due to medications used for treating psychoses.
• Metformin is an oral medication and Victoza is administered by injection under the skin (subcutaneously).
• Brand names of metformin include Glumetza, Glucophage, and Fortamet.
• Side effects of metformin and Victoza that are similar include nausea, vomiting, and diarrhea.
• Side effects of metformin that are different from Victoza include gas, bloating, and loss of appetite.
• Side effects of Victoza that are different from metformin include constipation, upper respiratory tract infection, headache, flu-like symptoms, dizziness, sinusitis, back pain, and injection site reactions.

Metformin is an oral drug used to treat type 2 diabetes that lowers blood glucose (sugar) by influencing the body's sensitivity to insulin. Metformin works to increase the sensitivity of liver, muscle, fat, and other tissues to the uptake and effects of insulin, which lowers blood glucose levels. Metformin does not increase the concentration of insulin in the blood and does not cause excessively low blood glucose levels (hypoglycemia) when used alone. Metformin can reduce complications of diabetes such as heart disease, blindness, and kidney disease. Metformin is also used to treat polycystic ovaries and weight gain due to medications used for treating psychoses.

Victoza (liraglutide) is used with diet and exercise to improve control of blood sugar in adults with type 2 diabetes. Victoza works like the hormone GLP-1 (7-37) to slow food leaving the stomach, to help prevent the liver from making too much sugar, and to help the pancreas produce more insulin when blood sugar levels are high.

Metformin

The most common side effects with metformin are

• nausea,
• vomiting,
• gas,
• bloating,
• diarrhea and
• loss of appetite.

These symptoms occur in one out of every three patients. These side effects may be severe enough to cause therapy to be discontinued in one out of every 20 patients. These side effects are related to the dose of the medication and may decrease if the dose is reduced.

Metformin may also cause:

• weakness or lack of energy
• respiratory tract infections,
• low levels of vitamin B-12,
• low blood glucose (hyperglycemia)
• constipation,
• indigestion, muscle pain,
• heartburn, and
• chills.

A serious but rare side effect of metformin is lactic acidosis. Lactic acidosis occurs in one out of every 30,000 patients and is fatal in 50% of cases. The symptoms of lactic acidosis are

• weakness,
• trouble breathing,
• abnormal heartbeats,
• unusual muscle pain,
• stomach discomfort,
• light-headedness, and
• feeling cold.

Patients at risk for lactic acidosis include those with reduced function of the

• kidneys or liver,
• congestive heart failure,
• severe acute illnesses, and
• dehydration.

Victoza

• The most common side effects of Victoza are
  • Nausea
  • Vomiting
  • Diarrhea
  • Constipation
  • Upper respiratory tract infection
  • Headache
  • Flu-like symptoms
  • Dizziness
  • Sinusitis
  • Back pain
  • Reactions at the injection site
• Combining Victoza with insulin or drugs that stimulate release of insulin (for example, glyburide) may increase the occurrence of low blood sugar (hypoglycemia). The dose of insulin or the insulin release stimulating drug should be reduced.
• There have been reports of acute pancreatitis associated with the use of Victoza. Patients developing severe, persistent abdominal pain that might be caused by pancreatitis, should seek prompt medical attention. If pancreatitis is suspected, Victoza should be discontinued and not started again until the presence of pancreatitis has been excluded.
• Victoza can cause thyroid tumors that occur more frequently at higher doses and with longer duration of treatment. Since Victoza is a synthetic protein patients may develop antibodies to Victoza. Victoza antibodies may reduce the effectiveness of Victoza.

Metformin

• For treating type 2 diabetes in adults, metformin (immediate release) usually is begun at a dose of 500 mg twice a day or 850 mg once daily. The dose is gradually increased by 500 mg weekly or 850 mg every two weeks as tolerated and based on the response of the levels of glucose in the blood. The maximum daily dose is 2550 mg given in three divided doses.
• If extended tablets are used, the starting dose is 500 mg or 1000 mg daily with the evening meal. The dose can be increased by 500 mg weekly up to a maximum dose of 2000 mg except for Fortamet (2500 mg of Fortamet, once daily or in two divided doses). Glumetza tablets (500 -1000mg formulations are given once daily (either 1000 to 2000mg). Fortamet and Glumetza are modified release formulations of metformin. Metformin should be taken with meals.
• For pediatric patients 10-16 years of age, the starting dose is 500 mg twice a day. The dose can be increased by 500 mg weekly up to a maximum dose of 2000 mg in divided doses.
• Children older than 17 years of age may receive 500 mg of extended-release tablets daily up to a maximum dose of 2000 mg daily. Extended-release tablets are not approved for children younger than 17 years of age.
• Metformin-containing drugs may be safely used in patients with mild to moderate renal impairment. Renal function should be assessed before starting treatment and at least yearly.
• Metformin should not be used by patients with an estimated glomerular filtration rate (eGFR) below 30 mL/minute/1.73 m2 and starting metformin in patients with an eGFR between 30-45 mL/minute/1.73 m2 is not recommended.
• Metformin should be stopped at the time of or before administering iodinated contrast in patients with an eGFR between 30 and 60 mL/minute/1.73 m2; in patients with a history of liver disease, alcoholism, or heart failure; or in patients who will be administered intra-arterial iodinated contrast. Kidney function should be evaluated 48 hours after receiving contrast and metformin may be restarted if kidney function is stable.

Victoza

• Victoza is injected under the skin of the abdomen, thigh, or upper arm.
• Each pre-filled pen can deliver 0.6, 1.2, and 1.8 mg doses. The initial dose is 0.6 mg daily for one week.
• The initial dose helps the body to build a tolerance to stomach related side effects.
• Victoza is not effective for controlling blood glucose.
• After one week the dose is increased to 1.2 mg daily.
• The maximum dose is 1.8 mg daily.

Metformin

• Cimetidine (Tagamet), by decreasing the elimination of metformin from the body, can increase the amount of metformin in the blood by 40%. This may increase the frequency of side effects from metformin.
• Ioversol (Optiray) and other iodinated contrast media may reduce kidney function, which reduces elimination of metformin, leading to increased concentrations of metformin in the blood. Metformin should be stopped 48 hours before and after use of contrast media.
• Thiazide diuretics, steroids, estrogens, and oral contraceptives may increase blood glucose and reduce the effect of metformin. When these drugs are stopped, patients should be closely observed for signs of low blood glucose.
• Alcohol consumption increases the effect of metformin on lactate production, increasing the risk of lactic acidosis.

Victoza

• Victoza slows down transit of food and drugs through the intestine and, therefore, may reduce the absorption of drugs that are taken orally. Although Victoza did not significantly affect the absorption of oral drugs tested in studies, it is still prudent to separate administration of Victoza and oral medications.
• Combining Victoza with insulin or drugs that stimulate release of insulin (for example, glyburide [Micronase, Diabeta, Glynase, Prestab]) may increase the occurrence of low blood sugar (hypoglycemia). The dose of insulin or the insulin release stimulating drug should be reduced.

Metformin

• There are no adequate studies in pregnant women. Most experts agree that insulin is the best treatment for pregnant women with diabetes.
• Metformin is excreted into breast milk and can, therefore, be transferred to the nursing infant. Nursing mothers should not use metformin.

Victoza

• There are no adequate studies of Victoza in pregnant women. Most experts agree that insulin is the drug of choice in pregnant women with diabetes.
• There are no adequate studies of Victoza in nursing mothers, and it is not known whether Victoza is excreted in human breast milk.