Most of us take medication without thinking too much about what happens after we swallow it. It works, we feel better, and we move on. That is completely reasonable for short-term treatment. But if you are on medication every single day, it is worth understanding two organs that are working hard behind the scenes on your behalf: your liver and your kidneys.
This is not a reason to worry about your treatment. It is a reason to stay curious about your health and keep up with the check-ins your GP recommends.
What your liver actually does with your medication
Think of your liver as the body’s processing plant. When a tablet reaches your stomach and gets absorbed into the bloodstream, the liver is the first major stop. It breaks the medication down, converts it into a usable form, and decides what gets sent out to the rest of the body.
That process works smoothly for most people most of the time. Where it can become a consideration is with medications taken daily over months or years, or with certain drugs that put more demand on the liver than others. Paracetamol is a good example. At the recommended dose it is safe and well tolerated. At higher doses, or taken regularly alongside alcohol, the liver struggles to keep up with the breakdown process and the strain shows up in elevated liver enzyme levels.
Some long-term medications, including certain treatments for cholesterol and some antibiotics, can also affect liver enzymes over time. This is exactly why liver function tests are a routine part of monitoring for people on these kinds of treatments. It is not a sign something is wrong — it is how your GP stays ahead of anything that might need adjusting.
What your kidneys do with what is left
Once the liver has done its job, the processed medication moves through the bloodstream to the kidneys. The kidneys filter the blood continuously, pulling out waste products and clearing medication from the system through urine. It is quiet, constant work, and your kidneys are remarkably good at it.
The issue with certain medications is that they can affect how well the kidneys do that filtering. Some commonly used anti-inflammatory pain relievers, for example, can reduce blood flow to the kidneys when used regularly over a long period. Kidneys need steady blood flow to function properly, and sustained reduction in that flow can gradually affect how efficiently they work.
For people with existing kidney concerns, or those on multiple medications, the kidneys may also clear some drugs more slowly than expected. This can cause medication to build up in the system rather than clearing out at the right rate, which is one of the reasons your GP sometimes prescribes a lower dose than you might expect. It is a thoughtful adjustment, not a cautious guess.
Who needs to pay more attention to this
For a healthy adult on occasional or short-term medication, the kidneys and liver handle their workload without any issue. The conversation becomes more relevant for people managing a chronic condition and taking daily medication over the long term, older adults whose organ function naturally changes with age, and anyone taking more than one medication simultaneously.
None of this means chronic medication is dangerous. It means that staying on track with your medication properly includes periodic checks on how your body is handling it.
The simple step that keeps this in check
A routine blood test is all it takes to see how your kidneys and liver are functioning. These checks are included in standard screening blood tests and require no special preparation. For anyone on long-term medication, they are a straightforward way to catch anything worth addressing early, long before it becomes a problem.
If you have been on chronic medication for a while and have not had organ function checked recently, bring it up at your next GP visit. It is a five-minute conversation that is genuinely worth having.
If that check-in is overdue, our GPs at Take Care Clinic in Lonehill, Johannesburg are here to help. Book a time that works for you.
