There are many things that can be done on a daily basis to manage kidney disease and reduce the risk of kidney damage, including taking medications.
Which medications are used to protect the kidneys?
Angiotensin-converting enzyme inhibitors (these usually end in ‘pril’) and angiotensin receptor blockers (these usually end in ‘sartan’)
Medications that lower blood pressure also help slow kidney disease. Two types of blood pressure medicines, angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs), play a special role in protecting the kidneys. Each has been found to slow kidney damage in people with diabetes who have high blood pressure.
These medications either prevent or block a hormone that tells blood vessels to tighten, which allows the blood vessels to open and thus reduce blood pressure. For most people with diabetes, a blood pressure target of less than 130/80 mm Hg is sufficient for kidney protection. Both ACE inhibitors and ARBs can reduce the risk of developing kidney disease in diabetes, independent of their effect on blood pressure, and they can also protect against the progression of kidney disease.
Is special monitoring required for these medications?
It is important that people with diabetes who are taking an ACE inhibitor or ARB have their serum creatinine and potassium levels checked within one to two weeks of starting the medication, when the dosage is increased, or during times of acute illness. (Creatinine is a waste product in your blood. It tells how well your kidneys are working.)
This is important because your healthcare team needs to check your eGFR (short for estimated glomerular filtration rate). Your eGFR is a number based on your blood test for creatinine.
If there is a greater drop in eGFR than expected at initiation of these medications, other kidney tests sometimes need to be done. It is interesting that there is an expected slight drop in eGFR when these medications are started but over time people on these medications will have a higher eGFR. The drop in eGFR means that the pressure in the kidney has decreased, which ultimately will prolong the life of the kidney. During times of illness or dehydration eGFR can also decrease and potassium levels can increase, especially if people have known kidney disease.
High potassium levels can be dangerous and ways to prevent this must be undertaken. This might involve a change in diet or addition of another medication (for example, a diuretic), a decrease in dose of the ACE inhibitor or ARB, or even discontinuation of these medications altogether. However, because these medications are so helpful for the heart and kidneys, many things are tried first before discontinuing them.
Key point: Adults with diabetes and kidney disease with either hypertension or albuminuria should receive an ACE inhibitor or an ARB to delay the progression of kidney disease.
Sodium-glucose co-transporter-2 inhibitors (these usually end in ‘flozin’)
Sodium-glucose co-transporter-2 (SGLT2) inhibitors are a newer class of blood sugar lowering medications, with two important influences on risk factors for kidney disease in diabetes: improvement in glycemic control and reduction in blood pressure. This class of medication works by preventing the kidneys from reabsorbing glucose and sodium from the urine back into the blood. Glucose is therefore removed from the body through urine. As a result, glucose in the blood decreases.
What is the effect of SGLT2 inhibitors on kidney health?
Studies have found lower rates of kidney disease progression with treatment of SGLT2 inhibitors in people with type 2 diabetes and cardiovascular disease. As a result, the recommendation is that this class be considered as second-line treatment in people with diabetes and pre-existing heart disease. One of the drugs from this class of medication, canagliflozin, was recently approved in Canada for use as an add-on therapy to diet and exercise to reduce the risk of end-stage kidney disease in adult patients with type 2 diabetes and diabetic kidney disease.
Not only do SGLT2 inhibitors improve blood sugar control and reduce the risk of major adverse cardiovascular events, they have also been shown to help with weight loss.
Side effects can include a 3 to 4 times higher risk of genital yeast infections, urinary tract infections and increased urination. As well, they may cause diabetic ketoacidosis, a rare but severe adverse event. This is more common in people who actually have type 1 diabetes and have been misclassified as type 2 or have long-standing type 2 diabetes who are on a multi-dose insulin regimen. Symptoms of diabetic ketoacidosis include nausea, vomiting, lack of appetite, abdominal pain, excessive thirst, difficulty breathing, confusion, unusual fatigue, or sleepiness. If this is suspected, prompt medical attention is required.
Key point: In addition to reducing blood sugar levels, SGLT2 inhibitors have been found to have cardiovascular and kidney benefits and can also help with weight loss. These medications should be considered as second-line treatment for people with type 2 diabetes at risk for heart disease. At this time, Health Canada has approved canagliflozin as the only medication to reduce the risk of end-stage kidney disease, doubling of serum creatinine and cardiovascular death in adults with type 2 diabetes and diabetic kidney disease with albuminuria.
Important information about sick day management
Several classes of medications that are used commonly in people with diabetes can either reduce kidney function during periods of illness or build up to a toxic level as kidney flow is reduced during times of sickness. These medications must be stopped temporarily until the person is well. For more information about managing diabetes when you are ill, including a printable sick day plan, click here.
It is important that people with diabetes have their blood and urine tested annually for early signs of kidney disease. If there are signs of kidney disease, medications and lifestyle changes can help delay further damage to the kidneys. The earlier kidney disease in diabetes is detected, the better, as it will reduce the chance of progression to advanced kidney disease and the need for dialysis or transplant.