November is National Diabetes Month. It seems appropriate that after Halloween candy and before Thanksgiving feasts, we take some time to think about blood sugar and discuss medicines for lowering blood sugar in those who have been diagnosed with Type 2 diabetes.
If a patient isn’t able to maintain target blood sugar levels with healthy eating and regular exercise, medication may be prescribed to help. While diabetes was first described in 2nd century Greece, it has not been until recent decades that we have effective medications for treating it. As more therapies have been developed it has become a complex task for clinicians and patients alike to keep up with the latest research. It is easy to focus on what is new but just as important to consider tried and true therapies.
One of those established therapies is metformin. This medication has a very good record for safety and efficacy but is often overlooked. Many patients come to me with misconceptions about the medication. Let’s clear up some of the confusion about metformin and other medications for controlling Type 2 diabetes.
Is metformin safe for my kidneys?
The short answer is yes, but it is easy to see why confusion exists. Clinicians monitor the renal function of patients on metformin and often reduce the dose of metformin or stop the medication entirely if renal function goes down. The reason is that metformin is cleared by the kidneys through urine. When kidney function goes down, the medication levels in the body will go up. Too much of a good thing can be a bad thing. When metformin levels are too high, lactic acid builds up. Something similar happens when we exercise, but the difference is that lactic acid from exercise will be cleared quickly when the exercise is done.
Is metformin safe for my heart?
Again, the answer is yes! A landmark trial called the United Kingdom Prospective Diabetes Study studied this question. Patients with diabetes were assigned to one of three groups. In the first group, patients were advised to use diet and exercise to manage blood sugar. The second group was given metformin, and the third group was given another class of blood sugar medication called a sulfonylurea and/or insulin. When the results were reported it was not surprising that the medication group had better cardiac outcomes than the group with lifestyle change alone. However, the group on metformin had better cardiac outcomes than the group using a sulfonylurea and/or insulin.
Is metformin still relevant with so many new medications on the market?
Yes! The American Diabetes Association recommends metformin as first-line therapy for patients with Type 2 diabetes mellitus. It is still a great choice because it works and it has an excellent safety record. Most patients can and should continue metformin even if other medications are added to their therapy plan by their provider. Metformin remains relevant, but you won’t see TV advertisements for it because its patent has expired so there is less incentive for manufacturers to market the medication. Their loss can be your gain; metformin is one of the most cost-effective medications for diabetes on the market.
Are there patients who should not take metformin?
Yes. Metformin is for patients with Type 2 diabetes mellitus. It is not indicated for patients with Type 1 disease. Type 1 disease occurs by a different process, and these patients are dependent on insulin. Patients with very low kidney function should not take metformin for the reasons discussed above. Also, patients who have an allergy or intolerance to metformin should not take it. The most common reason for stopping metformin in my patients is gastrointestinal symptoms. Metformin can cause loose stools and upset stomach. This can usually be managed with an extended-release version of the pill or a reduced dose, but the medicine just doesn’t agree with some patients. In these cases, it makes sense to find an alternative.
What are the new diabetes pills I see advertised?
Most of the diabetes pills that you are seeing advertised belong to a newer class of medications called SGLT2 inhibitor medications. As newer products, they have had highly visible advertising campaigns. The healthcare community is still getting experience working with these medications, but multiple studies show encouraging findings. In studies with acronyms like CANVAS and EMPEROR these medications are demonstrating the ability to not only reduce blood sugar but also show some protective effects on kidney and heart health. Patients at increased risk for renal and cardiac complications of diabetes may be good candidates for this class of medicine. In such cases, I recommend having a discussion with your medical provider to better understand risks and benefits.
What are the new non-insulin shots I see advertised?
While there are many types of insulin that can be injected, not all injections for diabetes are insulin. Another newer class of medications called GLP1 agonists are being heavily advertised. In all but one case they are given as an injection. The evidence is building that these medications may offer similar heart and kidney benefits to the SGLT2 inhibitors, and these medications may be right for some patients who are at increased risk. Discuss the risks and benefits with your health care provider.
When choosing a therapy plan with patients, I try to think about and describe what is known about safety, efficacy, common side effects and cost for any medication. When it comes to diabetes, metformin is still a great option for most patients with Type 2 diabetes. When patients can’t take metformin, need more than one medication, or have above-average cardiac or renal risk, they may benefit from discussing one of these newer options.
Understanding, monitoring and managing Type 2 diabetes doesn’t have a one-size-fits-all plan. Some people are able to control their blood sugar levels with healthy eating and exercise, others may need a combination of those lifestyle changes with medication or insulin to manage it. Patients should discuss options with a health care provider to develop the approach that works best for each individual.
Peter Barkett, MD, practices internal medicine at Kaiser Permanente Silverdale. He lives in Bremerton.
This article originally appeared on Kitsap Sun: Myths about diabetes medications