What do drugs do to the urinary system?

The human body is a fascinatingly complex structure that’s composed of several different but intertwined systems that regulate and control bodily functions. The central nervous system controls the functions of the brain and nerves, and the respiratory system determines how an individual breathes. But outside of the obvious, what exactly does the urinary system do? And how do drugs affect the urinary system?

This guide explores the ins and outs of this critical system so that you can better understand and take care of it. 

A brief guide to the urinary system

The urinary system at large

At a glance, it may seem quite clear what work the urinary system carries out in the human body: It’s the system that produces urine. While that’s true, it doesn’t paint the full picture and undersells the vital role that the urinary tract plays in human health.

Think of the urinary system as a counterpart to the digestive system, which includes the stomach and intestines and functions to extract nutrients from food and dispose of excess matter through feces.

The body’s urinary system handles the extraction of nutrients and the removal of waste, but it doesn’t draw from the stomach and intestines. Instead, the urinary system works by using the kidneys to filter blood, removing toxins, waste matter, and some water. This process creates urine, which the kidneys send to the bladder via two tubes called ureters. The kidneys also reabsorb the nutrients and send these useful substances back into the bloodstream¹.

At the end of this process, excess water, waste, and toxins are routed from the bladder through the urethra, where they are released as urine. 

How kidneys work

Your kidneys are the cornerstone of the urinary tract. These bean-shaped organs are made up of millions of small filters known as nephrons. Nephrons draw in blood from a renal artery (a blood vessel carrying blood from the heart to the kidneys) and remove small amounts of water, sodium, and potassium, as well as toxins and other substances the body no longer needs².

Once filtered out, these substances become urine passed down the ureters to the bladder, where they’re stored. Meanwhile, the rest of the water, nutrients, and proteins that haven’t been filtered out get deposited back into the bloodstream.

A healthy set of kidneys can process a few ounces of blood each minute. Throughout the day, they can filter toxins from up to 150 quarts of blood — meaning that all the blood in your body goes through this process several times per day.

The kidneys also perform several other crucial tasks, such as:

• Releasing hormones to help regulate blood pressure
• Maintaining the blood's pH balance
• Producing red blood cells that are vital for distributing oxygen throughout the body

The role of the bladder

Think of the bladder as a storage tank holding all the toxins collected in the urine. It keeps these substances from going back into the rest of the body.

The bladder also communicates information about the overall health of an individual’s urinary tract. Pain during urination, urinary discomfort, changes in urine color, and blood in the urine indicate that there’s something wrong with the renal system³. Without these signs, many people would not know when to seek medical attention for urinary conditions. 

Does drug use affect the urinary system?

All drugs introduced to the body — whether prescription, over-the-counter, or illicit — eventually make their way into the bloodstream. This means that, sooner or later, the kidneys must work to process any drugs in the body. 

It’s the urinary system’s job to separate nutrients and toxins, but some substances are trickier to process than others. This means that certain drugs may take a toll on the urinary system. How exactly does drug use affect the urinary system? That depends on the drug and its effects, which might impact the entire system or just the kidneys or the bladder. 

Can drugs affect your bladder?

Yes, drugs of various types can impact your bladder function. Long-term ketamine use, for example, has been shown to lead to several bladder issues⁴, including:

• Poor urinary control
• Increased urination frequency
• Frequent urination during the night

These issues may be the result of thickening of the muscle walls of the bladder, which leads to a lower overall bladder volume. 

Ketamine is also associated with bladder inflammation, which results in urinary discomfort and pain⁵. Amphetamines may also cause bladder dysfunction⁴.

Things look a little different for opioid users, who are more prone to experiencing urinary retention⁶, or the inability to fully empty the bladder. This leads to a persistent sense of having to urinate and general discomfort after urination, rather than relief.

While opioids are primarily used pharmaceutically for pain relief and recreationally to create a euphoria-inducing high, these drugs’ effects are more wide-reaching. Opioid use is known to inhibit the neural pathways involved in muscle contraction, which is part of why many opioid users report feeling relaxed. 

The drugs’ effect on your bladder results in the inability to properly contract the muscles involved in urination, preventing the complete evacuation of the bladder.  

Opioid users are also at risk for larger bladder issues. Many opioids, especially heroin, are associated with a significantly increased risk of bladder cancer⁴. While these instances of bladder cancer aren’t known to be more aggressive or more difficult to treat than other bladder cancers, this is still a serious and prevalent risk. 

How do drugs affect the kidneys?

Drugs affect the kidneys in several distinct ways, some more drastic than others. Some drugs, like alcohol, may cause an imbalance in electrolytes and minerals in your body, which makes it harder for your kidneys to bring these levels in your blood back into balance. These issues aren’t immediately dangerous, but they can become more drastic with chronic use and lead to other issues.

On the other end of the spectrum, alcohol, cocaine, MDMA, and opioids have all been known to cause muscles to break down. Muscle deterioration releases toxins that eventually end up in the bloodstream, often leading to severe kidney damage or failure⁷. 

Opioids can also cause numerous other issues. Opioid-induced dehydration or urinary retention, for instance, can cause various forms of kidney injury, leading to chronic kidney disease.

Additionally, injecting opioids increases a person’s risk of hepatitis B, hepatitis C, and HIV, all of which curb kidney function⁸.

Manage opioid use disorder (OUD) with help from Ophelia

At Ophelia, our mission is to make medication-assisted treatment (MAT) accessible to all individuals experiencing opioid use disorder. We’re dedicated to helping every patient find the necessary support and offering comprehensive treatment programs that include specialist referrals and patient-focused advocacy.