Researchers have found that the drug metformin might be more effective than others in controlling blood sugar.
People newly diagnosed with type 2 diabetes who are initially given the drug metformin are less likely to eventually need other drugs to control their blood sugar, a new study suggests.
Second drug or insulin
The study found that, of those started on metformin, only about one-quarter needed another drug to control their blood sugar. However, people who were started on type 2 diabetes drugs other than metformin often needed a second drug or insulin to control their blood sugar levels, the researchers said.
"This study supports the predominant practice, which is that most people are started on metformin," said lead researcher Dr. Niteesh Choudhry, an associate professor of medicine at Harvard Medical School in Boston. "Metformin might be more effective than others in controlling blood sugar," he noted.
"Metformin, which is one of the oldest drugs we have and which the guidelines recommend as being the first drug to use, is associated with a lower risk of needing to add a second drug or insulin compared to any of three other commonly used classes of drugs," Choudhry said.
The report was published in the online edition of JAMA Internal Medicine.
A hallmark of type 2 diabetes is insulin resistance, according to the American Diabetes Association (ADA). That means the body doesn't effectively use the hormone insulin. Insulin is produced by the pancreas and helps usher sugar from foods into the body's cells to be used as energy.
When people have insulin resistance, too much sugar is left in the blood instead of being used. Over the long-term, high blood sugar levels can lead to serious complications, such as heart and kidney disease, according to the ADA.
There are eight classes of oral type 2 diabetes medications, according to the ADA. Each class works a bit differently. For example, metformin makes the body's cells more sensitive to insulin. It also decreases the amount of sugar naturally produced in the liver, the ADA reports. Sulfonylureas, on the other hand, encourage the pancreas to produce more insulin, according the ADA.
For the current study, Choudhry's team collected data on more than 15,000 people starting treatment for type 2 diabetes from July 2009 through June 2013. The average follow-up time was slightly longer than one year.
Of those patients, almost 60 percent were initially treated with metformin, and about one-quarter began treatment with a sulfonylurea, such as Glucotrol, according to the study. Just 6 percent were started with a thiazolidinedione, such as Actos, and 13 percent with a DPP-4 inhibitor, such as Januvia, the report indicated.
The researchers found that around 40 percent of people taking a sulfonylurea, a thiazolidinedione, or a dipeptidyl peptidase 4 inhibitor (DPP-4 inhibitor) added a second drug to their diabetes treatment regimen during the study. Just 25 percent of those on metformin added an additional oral drug during the study period.
In addition, 5 percent of those started on metformin later added insulin to their treatment, according to the study. About 9 percent of those who started on a sulfonylurea, 6 percent started on a DPP-4 inhibitor and 6 percent started on thiazolidinediones, also took insulin, the investigators found.
Choudhry said that many patients are being started on other drugs, but this study indicates that treatment should start with metformin.
"These findings emphasize the use of metformin as the first-line drug for type 2 diabetes," he said.
Dr. Jodi Segal, co-director of the Centre for Drug Safety and Effectiveness at Johns Hopkins Bloomberg School of Public Health and co-author of an accompanying journal editorial, said, "It is already well established that metformin is the preferred first-line option for patients who can tolerate it."
But, she added that doctors should pay more attention to their patients' worries about needing to intensify therapy when choosing medications.
"Doctors might want to help their patients understand that intensifying therapy does not mean that the patient has failed," Segal said.
Dr. Joel Zonszein, director of the Clinical Diabetes Centre at Montefiore Medical Centre in New York City, doesn't think that metformin alone is sufficient to treat type 2 diabetes. He believes that treatment needs to aggressively lower blood sugar.
"We don't start treatment with a single drug," Zonszein said. "We use a combination from the get-go."
Zonszein said even this study shows that treatment with a single drug doesn't work. "So why do we wait to intensify treatment rather than treating more aggressively?"
Metformin is an oral blood-glucose-lowering drug.
Metformin is the active ingredient of Arrow Metformin, Austell-Metformin, Bigsens, Forminal, Glucophage, Metforal and Sandoz Metformin.
Metformin is also one of multiple active ingredients found in Glucovance (metformin + glibenclamide).
Metformin is an oral blood-glucose-lowering drug. It is prescribed in the treatment and management of type 2 diabetes (a disease caused by a problem in the way the body makes or uses insulin, which is necessary for glucose to move from the blood to the inside of the cells) that is not adequately controlled by diet and exercise alone.
Type 2 diabetes makes up 90 per cent or more of all cases of diabetes.
Treatment with oral anti-diabetic drugs should only be started once all lifestyle and dietary measures have been tried for at least three months and have not controlled blood glucose adequately. Once treatment with this medication is started, diet and exercise should however not be stopped.
Metformin is the oral anti-diabetic drug of choice in overweight type 2 diabetics. It induces mild loss of appetite and thereby helps to control weight.
Metformin can be used on its own - and treatment is often started with one drug only - or in combination with other oral blood-glucose-lowering drugs.
For metformin to remain effective, it needs to be taken regularly.
Lactic acidosis (high levels of lactic acid in the blood which may be fatal) is a potential, but rare side effect seen with the use of metformin. The use of alcohol while being treated with metformin increases the risk of lactic acidosis.
Generally, this medication is used when the body is still producing some insulin.
How does metformin work?
Metformin reduces the amount of glucose supplied by the liver, and also enhances the uptake of glucose in muscles. It furthermore reduces the absorption of glucose from the digestive tract into the bloodstream.
Drug schedule: schedule 3
Available as: metformin is available as tablets
What does it do? metformin lowers blood sugar
Overdose risk: high
Dependence risk: low
Is metformin available as a generic? no
Is metformin available on prescription only? yes
Onset of effect: within 2 hours
Duration of action: up to 15 hours
Dietary advice: metformin should be taken with meals to reduce gastrointestinal side effects
Stopping this medicine: consult your doctor before stopping this medication; diabetes may worsen with premature discontinuation
Prolonged use: long-term use may lead to anaemia as a result of vitamin-B12 depletion
Consult your doctor before using this drug if:
• you have congestive heart failure
• you have kidney or liver disease
• you have a history of alcohol abuse
• you are taking other medication
Pregnancy: avoid. Potential risk to the foetus has been reported. Consult your doctor before use, or if you are planning to fall pregnant.
Breastfeeding: avoid. This medication is passed through breast milk and may affect your baby adversely. Consult your doctor before use.
Porphyria: safe to use.
Infants and children: this medication is not intended for use in children.
The elderly: caution is advised in the elderly as adverse effects are more likely.
Driving and hazardous work: caution is advised as use of this medication may lead to dizziness or light-headedness. Avoid such activities until you know how this medication affects you.
Alcohol: avoid concomitant use of alcohol with this medication.
Possible side effects
Side effect Frequency Consult your doctor
Common Rare Only if severe In all cases
loss of appetite x x
metallic taste in mouth x x
nausea/ vomiting x x
diarrhoea x x
dizziness x x
confusion x x
abdominal bloating x x
rapid shallow breathing x x
unusual sleepiness/ weakness x x
rapid pulse x x
blurred vision x x
pulse x x
alcohol increased risk of lactic acidosis
cimetidine increased risk of metformin toxicity
corticosteroids may diminish effect on blood sugar
diuretics may diminish effect on blood sugar
Consult your doctor before using this drug if you have congestive heart failure, kidney or liver disease or if you have a history of alcohol abuse.
An overdose of this medication can be serious. Seek immediate emergency medical attention.
Adults: 500mg three times daily, or 850mg twice daily. Maximum dose is 3000mg/day.
Metformin is being used increasingly in treating polycystic ovarian syndrome (PCOS).
This material is not intended to substitute medical advice, but is for informational purposes only. Please consult a physician for specific treatment and recommendations