Health Tips

In my years practising as a pharmacist, one of the most common questions I get from patients, friends and relatives is:

 “Do medications for diabetes cause kidney failure?”

It seems that the public has a misconception on medication for diabetes and to clear up this misunderstanding, we first need to understand what exactly diabetes is.

Diabetes and its complications

Diabetes is a disease where the sugar level in one’s blood is too high. This chronic (long-term) disease may be classified into two types. Type I and Type II. Type 1 Diabetes occurs when there is insufficient insulin production by the body and usually occurs in younger patients such as children and teenagers; Type II Diabetes, on the other hand, affects older patients and is due to the body’s insensitivity towards insulin (where the body is not reacting to insulin) while in most cases insulin production will also decrease over time. In later stages of Type II Diabetes, patients can develop insulin insufficiency just like Type I Diabetes, but there is beyond the scope of our discussion. In case if you are wondering, insulin is a hormone produced by the pancreas and is responsible for controlling blood sugar levels.

When blood sugar levels remain high for long periods of time, it can cause many complications of diabetes. These complications are divided into macrovascular (affecting larger blood vessels) and microvascular (affecting smaller blood vessels). Examples of macrovascular complications are atherosclerosis (blockage of blood vessels due to cholesterol plaques), heart attack and stroke. Microvascular complications are usually seen in the form of damage to the eye, nerves or kidneys.

Really? Medications for diabetes do not cause kidney damage or failure?!

Now we shall move on to discuss the types of medications available for diabetes. Generally, they can be classified into two groups; Oral medications and injection medications.

Most injectable medications for diabetes are man-made insulin. This is primarily used in patients with Type I Diabetes and late stages of Type II Diabetes to replace the low levels or absence of insulin that is required by the body. Since man-made insulin is very similar to the endogenous (body’s own) insulin, its common side effect is similar to endogenous insulin, which includes low blood sugar, weight gain, etc. Man-made insulin, therefore, does not cause kidney failure.

Oral medications for diabetes are used in Type II Diabetes only and there are many types available. Some work by stimulating the pancreas to secrete more insulin, while others increase the sensitivity of the body to insulin.

Medications that work by stimulating the pancreas to secrete more insulin have similar side effects to that of insulin, since it causes increased amounts of insulin to circulate in the body. Furthermore, these medications are not known to cause kidney damage.

Medications that increase the sensitivity of the body to insulin generally do not cause problems with weight gain, but may cause one’s stomach to feel bloated, nausea and even vomiting. However, they do not cause kidney damage either.

Then why do people claim that medications for diabetes cause kidney damage?

When patients with diabetes present with kidney damage or failure, the most likely cause is that the patient’s blood sugar level was not well-controlled over a long period of time thereby allowing complications of diabetes to develop. When kidney damage or failure happens, the doctor may choose to stop certain diabetes medications for the patient. It is exactly this action that makes patients think that the medication(s) were the cause of the kidney failure, hence the doctor stopped it. The truth cannot be farther from that. These are medications that are usually cleared from the body by the kidneys. When the kidneys fail to function properly, the medications do not get cleared from the body efficiently and can build-up in the body excessively to cause toxic effects due to overdose. Hence, the doctor has no choice but to stop or reduce the medications.

I see. Then who should I trust when I have queries on health?

I sincerely hope that this article has cleared many doubts of our readers and please follow your doctor’s instructions to take your medications. If you have any doubts, always feel free to talk to your doctor or pharmacist. They are more than happy to help you!

Cover image credit: Medical News Today

Written by

Dr Pou Wee Gan