When it comes to the treatment of hypertension, one of the first types of drugs that a family practitioner or cardiologist will prescribe is going to be a diuretic. You may have heard of diuretics, which are more commonly described as “water pills", before. When the kidneys are working properly, these medications can work wonders by influencing how elements like sodium, potassium and chlorine are absorbed within the kidney apparatus. As these elements are secreted into the kidney tract, water is likely to follow. As a result, a person taking diuretics will essentially be removing excessive water from their body.
What exactly is kidney failure?
To start off with, it may be a good idea to address what exactly a term like “kidney failure” actually means. When your doctor says that you have kidney failure or chronic kidney disease, you may think the situation is much more serious than it actually is, since you know that you require at least one semi-functional kidney to be able to live.
As a person ages, the kidneys will start to become less and less effective at filtering out toxins and regulating the water-electrolyte balance within the body. As a result, parameters that are used to measure the function of the kidneys — like creatinine and GFR — will begin to change.
When a patient has a comorbidity (another medical condition in addition to kidney damage or failure), on the other hand, kidney damage is likely to accelerate — and this is when you may need to start making appointments at your local nephrologist. Some of the most common conditions that significantly damage kidney function would be type 2 diabetes, alcohol consumption, and smoking.
These patients will almost always have hypertension as well, because the kidneys are one of the main organs to regulate blood pressure. In times of low blood pressure, the kidneys are able to secrete enzymes, like the ACE enzyme, to help increase the blood pressure. When there is damage like atherosclerosis along the blood vessels walls, the kidneys are able to increase the pressure in the vessels to help blood squeeze through the narrow space. Physiologically, this is a good thing so you can keep blood moving to vital organs but if this continues to happen without intervention from a doctor, it can lead to serious medical problems.
The interaction between diuretics and kidney function
Now that you know a little more about how the kidneys function and how your blood pressure is regulated, we can focus more on what these water pills — diuretics — can do to influence these measurements.
Diuretics help reduce excess water within the body to help reduce the amount of fluid within, and pressure on, your blood vessels. This causes blood pressure to be reduced.
There are a few different types of diuretics that doctors can choose from when it comes to trying to lower your blood pressure. The main difference between these medications is the specific part of the kidney that is affected when these medications are administered. The most common classes that we typically use would be loop diuretics like furosemide (Lasix), potassium-sparing diuretics like aldosterone, and thiazides. They all do a good job controlling your blood pressure but in most patients, we will typically start with a loop diuretic and then build up from there if necessary, if the patient's blood pressure is still high.
As you can imagine, medications are substances that are not natural and are designed to be a temporary solution to a problem like hypertension. When chronic conditions like diabetes and hypertension start to influence the function of the kidneys more dramatically, it will become harder and harder for a patient to be able to manage their blood pressure through dieting alone and medications will be started.
According to different studies, diuretics, for the most part, are completely safe for the kidneys but over time, the kidneys will develop a “pseudo-tolerance” to these diuretics because of prolonged use. The dose of the medication will then likely need to be increased in order to have a lasting effect. You may notice the medications are starting to fail if there is more and more swelling in your lower legs. This is a sign that the body is storing extra fluid and will need a stronger diuretic to help remove the fluid.
Diuretics work by blocking ion channels to help regulate the flow of water. Because of this, some of the most important things for you to know as a patient is the type of diuretic you are taking and whether you will need to monitor your potassium or sodium levels routinely.
If you take these blood pressure medications without an occasional check-up with your family doctor, you could be creating an ion deficiency that could lead to symptoms like chest pain, numbness or palpitations of your heart (often mimicking a heart attack). Make sure that you visit your family doctor within a week of starting a new diuretic or changing the dose to make sure the drug is not too strong for you.
Another very important thing for you to realize as a patient is that if you are taking a diuretic to help manage hypertension, these medications will only have a limited impact at controlling your blood pressure. Even if a doctor wishes to add more medications like beta blockers or ACE inhibitors to help control the blood pressure, studies indicate that you can expect your blood pressure to be reduced by around 30%.
These drugs also come with a panel of side effects that can lead to patients needing to spend a few days in the hospital if left unchecked.
A far more effective strategy at reducing your blood pressure would be through changing your lifestyle, namely by dieting and exercising. Studies show that even losing a few pounds can drop blood pressure levels by 20/10 mmHg if you are currently overweight. This can be the difference between requiring medications or not. Losing around 10 kilograms can reduce blood pressure values by over 40%.
Your thoughts on this