Is Blood Pressure Medication Hard On Your Kidneys

Overview

The kidneys perform the vital function of filtering liquids and toxins from the blood. If they completely fail to perform their function these unwanted substances build up and cause swelling around the body. This condition is called uremia and can cause fatigue, nausea, and if left untreated, results in coma and eventually death. It’s crucially important that our kidneys operate as they should.

There is a close connection between blood pressure and kidney function: abnormal blood pressure can adversely affect kidney function and vice-versa. Following this, common sense would lead us to believe that anything good for blood pressure must also be beneficial for the kidneys, but is this always the case?

Understanding blood pressure

Blood pressure is a measure of the amount of force required by the heart to pump blood around the body.¹ This comes in two forms: systolic and diastolic. Systolic blood pressure refers to the blood pressure measured when your heart pumps out blood, diastolic is the measure when your heart is resting between beats.¹

If you’ve ever had your blood pressure taken you might be familiar with readings in the form of “90 over 60” or “120/80”; the first number indicates systolic pressure and the second diastolic.  

Causes and risk factors

High blood pressure is a risk to health because excess pressure puts strain on the blood vessels (arteries, veins, and capillaries) as well as vital organs such as the heart. 

High blood pressure, or hypertension, is considered to be any values of systolic pressure above 130 or diastolic at 80 or higher.² 

The causes of the condition can vary: 

• It can be due to a hereditary condition (ethnicity is a factor)
• A lack of exercise
• Too much caffeine or stimulants
• Alcohol
• Obesity or a poor diet
• Smoking
• Lack of exercise or poor sleep³

Low blood pressure is also a threat to health and often comes about as a side-effect of medication. 

Treatment

If the condition isn’t severe, the opposite of the causes can act as the treatment: 

• Undertaking more aerobic exercise, this causes the heart to beat faster and stronger to encourage healthy function
• Avoid alcohol and cigarettes
• Reconsider the amount of caffeine you consume. The Mayo clinic advises limiting caffeine intake to 200 milligrams (two cups) a day⁴
• Eat a more balanced diet and reduce your intake of sodium chloride (salt).
• Try to get the recommended 7-9 hours of sleep per night⁵ 
• Blood pressure medication

Kidney disease

Kidney Disease is a condition characterised by the kidney’s inability to filter the blood. When this happens fluid and waste toxins can build up in the body making us unwell. 

Many people live with kidney disease, the CDC estimates that 15% of the population, or 37 million people live with chronic kidney disease.⁶

Chronic kidney disease forces the heart to pump harder to ensure that blood reaches the kidneys, this can result in heart disease, and eventually heart failure, which is the leading cause of death in the United States.⁷

Common causes

The biggest causes of kidney disease are diabetes and hypertension.⁸ 

High cholesterol is also a prominent cause. The reason for this is that the buildup of plaque, or cholesterol, can block blood vessels and may clog the arteries and cut off blood flow to the kidneys, preventing them from filtering blood. 

Acute kidney injury can also cause damage which prevents the kidney from functioning and may justify a kidney transplant.

Interestingly, cardiovascular disease (heart disease) can be a cause of kidney disease as well as one of its symptoms. Failure of the heart to effectively pump blood through the kidney, can cause blood to build up within the organ leading to damage and disease.

Lesser known causes include infections, heavy metal blood poisoning, genetic conditions, chemicals that are toxic to the kidneys, and lupus.⁹

Treatment

There’s no cure for chronic kidney disease, but there are a number of methods to ameliorate the symptoms: 

• Conventional Dialysis, or hemodialysis, can be undertaken. This is a method of filtering the blood by pumping it outside of the body to a specially designed machine which essentially does the job of the kidneys. Thus mitigating any adverse symptoms
• Peritoneal Dialysis. This is a specific type of dialysis used for kidney failure. It involves filtering blood using the lining of the abdomen or belly¹¹
• Healthy lifestyle changes. Regular exercise, reduction in the intake of alcohol, salt and sugars, quitting smoking
• Medicine can be taken to reduce blood pressure and cholesterol.
• A kidney transplant can replace the poorly functioning organ¹⁰

A top way to combat kidney disease is to target its biggest causes, i.e., diabetes and hypertension. 

Blood pressure medication, along with the advice in the section above, is an effective way to treat hypertension. Diabetes can be mitigated by a switch to a healthier lifestyle, although diabetes can often be hereditary. Monitoring blood sugar levels is a good indicator and early warning of the condition.¹²

What are blood pressure medicines

There are many blood pressure medicines which aim to tackle high blood pressure in a variety of different ways. Some of the main medications are listed below: 

• Beta Blockers reduce your heart rate, and the amount of force with which it pumps, to relieve pressure on the blood vessels and organs. 
• Calcium channel blockers. These prevent calcium from entering the muscle cells of the blood vessels and heart, thus weakening the muscles and causing the heart to pump less forcefully and the blood vessels to relax and open more. 
• ACE Inhibitors. Angiotensin is a chemical which causes the narrowing of the arteries, especially in the kidneys. ACE inhibitors force the body to produce less angiotensin, thus widening the arteries and other blood vessels.
• Diuretics. These cause you to urinate. The idea is to flush excess water and salt from the body, therefore reducing the strain on the kidneys and by extension reducing hypertension.^{13, 14}

Is blood pressure medication hard on your kidneys

The majority of blood pressure medications do not harm the kidneys. Means of mitigating hypertension will also reduce the strain on the kidneys by encouraging healthy blood flow allowing organs to function as they should. 

There are certain cases where the contrary is true. There is evidence to suggest that certain blood pressure medications may be damaging to the kidneys when used over a long period of time.

When to stop taking blood pressure medicines

The NHS advises to stop taking blood pressure medication if you experience any of the associated side effects of the particular medicine that has been prescribed to you. 

Blood pressure medicines that damages kidney

Renin cells play a key role in regulating blood pressure via hormonal release, especially within the kidneys.¹⁵  Some blood pressure treatments can have a detrimental effect on renin cells and cause them to malfunction, causing the generation and build up of muscle cells within the kidneys and blood vessels. This increase in muscle cell can impede blood flow and cause damage to the kidneys.¹⁶

There is evidence to suggest that long term use of ACE inhibitors, and angiotensin II receptor blocker (ARB), can be detrimental to renin cells and cause the above behavior.¹⁶

There is also a potential for diuretics to damage the kidneys by reducing the level of fluid in the body to a point which inhibits the kidneys normal function.¹⁷ 

Complications

Complications can arise if we stop taking prescribed medication without consulting a medical professional. Hypertension medication is prescribed in the best interest of patients’ health.

When to seek medical attention

 Kidney disease is a very manageable condition. That being said, it is advised to see a doctor if you believe you may have the condition or exhibit any of the symptoms. 

Hypertension is a main cause of heart failure or attack the  American heart Association provides a list of early warning signs which if someone is exhibiting, contact emergency services. 

Summary

Hypertension and kidney function are intrinsically related. Good functioning blood pressure will lead to the good functioning of the kidneys, but unfortunately the opposite is also true. High blood pressure and kidney disease are common conditions which many people live with - so don’t panic! 

There is recent evidence to suggest a relationship between blood pressure medication and renin cell function. There is an older, established relationship between diuretics, dehydration and kidney function. If you’re concerned about any of these, contact your doctor or a healthcare professional.

A healthy lifestyle is a good way to mitigate the causes of high blood pressure and kidney disease.