Gan Pou Wee
M.Pharm, MBBS, BCPS, R.Ph
It is frequently circulated in the social media and in forwarded messages that medications for diabetes cause kidney failure. This urban myth has caused lingering fear among many diabetic patients, to a point that some patients even stop taking their medications. So, is this true, or is it merely an urban legend?
Poorly-controlled diabetes causes kidney failure
It is a well-known fact that diabetes can cause kidney failure in the long term, and having poorly-controlled diabetes accelerates the rate of kidney failure. Good blood sugar control prevents the complications of diabetes or delays the onset of these complications. The complications of diabetes are detailed in another article here.
Medications for diabetes excreted from kidneys
Many medications for diabetes are known to be excreted from the kidneys. Some examples are gliclazide (Diamicron®), metformin (Glucophage®) and sitagliptin (Januvia®). Since these medications are dependent on a functioning kidney to be excreted from the body, kidney failure will result in the built up of these medications in the body, causing unwanted side effects. However, it is worth noting that these medications are not known to cause kidney damage.
Insulin is also excreted from kidneys
Furthermore, insulin, the hormone that controls blood sugar, is also excreted from kidneys. As kidney function declines in a diabetic patient, insulin produced by the body may also accumulate to high enough concentrations that it appears as if the diabetes has been cured. The patient may find that even when taking less or no medications, their blood sugar concentrations seem to be improving. However, this perceived improvement does not last long. Once the pancreas is finally exhausted of its insulin producing capability, high blood sugar levels will return.
The root of the misunderstanding
Without proper explanation from healthcare professionals pertaining to the corresponding anti-diabetic medication dose reduction or medication switch when kidney function declines, patients seem to misconstrue that these medications are the actual cause of the kidney failure.
The truth could not be further than that. As mentioned earlier, these medications are excreted by kidneys, hence, to prevent built up of these medications in the patient’s body and subsequent side effects, their doctor will reduce or remove the medication(s).
The importance of blood sugar control
It is very important for diabetic patients to achieve good control of their blood sugar and blood pressure as this will aid them in preventing complications of diabetes and kidney failure. All in all, patients should remember that the medications for diabetes are NOT the cause of kidney failure. It is by NOT taking medications that diabetic patients develop kidney failure as their diabetes progresses.
- Drug Information Handbook. (2017). Lexi-Comp Inc.
- Stratton, I., Cull, C., Adler, A., Matthews, D., Neil, H. and Holman, R. (2006). Additive effects of glycaemia and blood pressure exposure on risk of complications in type 2 diabetes: a prospective observational study (UKPDS 75). Diabetologia, 49(8), pp.1761-1769.