Yes, several common medications can trigger acute kidney injury (AKI) or make an existing kidney problem worse, especially if you are already unwell with another illness. These drugs are often called ‘nephrotoxic’ because they can interfere with the way the kidneys filter blood or reduce the blood flow the kidneys need to function safely.
While these medications are safe for most people when used correctly, they can become a risk factor during periods of dehydration, high fever, or severe infection. In the UK, healthcare providers often advise patients on certain long-term medications to temporarily pause them during an acute illness to protect their kidney health. This is a key part of NHS patient safety guidance designed to prevent avoidable kidney damage. In this article, you will learn which groups of medicines are most associated with AKI, why they affect the kidneys, and how to manage them safely.
What We’ll Discuss in This Article
- Identifying common medication groups that can trigger AKI
- Understanding the mechanism of ‘nephrotoxicity’
- The importance of ‘Sick Day Rules’ for medication safety
- How pre-existing conditions increase the risk of drug-induced AKI
- Clinical evidence regarding medication management and renal outcomes
- Safe steps to take if you are unwell while on long-term medication
Which medicines are most likely to affect the kidneys?
Several classes of drugs are known to potentially trigger AKI. The most common include Non-Steroidal Anti-Inflammatory Drugs (NSAIDs), certain blood pressure medications, and specific antibiotics. These drugs don’t necessarily ‘poison’ the kidneys directly in every case; rather, they often change the internal pressure within the kidney’s filtration units (nephrons) or reduce the kidneys’ ability to compensate for low blood pressure.
According to NICE guidelines, clinicians must review medication history for anyone presenting with a sudden decline in kidney function. Stopping or adjusting these ‘culprit’ drugs is often the first step in clinical management to allow the kidneys to recover.
High-Risk Medication Groups:
- NSAIDs: Common painkillers like ibuprofen, naproxen, and high-dose aspirin.
- ACE Inhibitors: Blood pressure medications such as ramipril, lisinopril, and enalapril.
- ARBs: Blood pressure medications like losartan, candesartan, and valsartan.
- Diuretics: Often called ‘water tablets’, such as furosemide or spironolactone.
- SGLT2 Inhibitors: Certain modern medications used for type 2 diabetes or heart failure.
How do these medicines trigger AKI?
Medicines trigger AKI through various physiological pathways. Some reduce the flow of blood into the kidney, while others prevent the kidney from maintaining the correct internal pressure required for filtration. When a person is dehydrated perhaps due to a stomach bug or the flu the kidneys already have less blood to work with. Adding a medication that further reduces blood flow or pressure can be the ‘tipping point’ that leads to acute injury.
The kidneys use complex chemical signals to keep blood flowing. NSAIDs, for example, block ‘prostaglandins’ which normally keep the blood vessels leading to the kidney open. ACE inhibitors and ARBs, on the other hand, relax the blood vessels leading out of the kidney filters, which can cause the filtration pressure to drop too low if the patient is already dehydrated.
Mechanism of Action Table
| Medication Type | Clinical Effect on Kidneys | Risk Factor |
| NSAIDs | Constricts the blood vessels entering the kidney | Dehydration, heart failure |
| ACE Inhibitors/ARBs | Reduces the pressure inside the kidney filters | Low blood pressure, sepsis |
| Diuretics | Increases fluid loss, leading to lower blood volume | Vomiting, diarrhoea, heat |
| Aminoglycosides | Direct toxic damage to the kidney’s filtering tubes | Long-term use or high doses |
The NHS ‘Sick Day Rules’
To prevent medication-triggered AKI, the NHS promotes ‘Sick Day Rules’. This guidance advises patients to temporarily stop taking specific medications if they develop an illness that causes dehydration. This is a preventative measure to ensure the kidneys aren’t under extra stress while the body fights an infection or manages fluid loss.
It is essential that patients do not stop taking prescribed medications permanently without consulting their GP or pharmacist.
Medications to Pause During Illness (The ‘DAMN’ acronym):
- D – Diuretics (water tablets)
- A – ACE inhibitors and ARBs (blood pressure meds)
- M – Metformin (a diabetes medication that can build up if kidneys fail)
- N – NSAIDs (anti-inflammatory painkillers)
To Summarise
Certain medicines, particularly NSAIDs, blood pressure tablets, and diuretics, can trigger acute kidney injury by altering blood flow and pressure within the kidneys. This risk is significantly higher when a person is dehydrated or suffering from a severe infection. Following ‘Sick Day Rules’ and ensuring a clinical review of medications during acute illness are vital steps in protecting kidney function and preventing avoidable injury.
If you experience severe, sudden, or worsening symptoms, call 999 immediately.
Can I still take paracetamol if I have AKI?
Yes, paracetamol is generally considered safe for the kidneys and is the preferred painkiller when NSAIDs like ibuprofen must be avoided.
Will my kidneys recover once I stop the medicine?
In many cases of drug-triggered AKI, kidney function returns to its previous level once the medication is stopped and fluid levels are restored.
Does ibuprofen always cause AKI?
No, in healthy people who are well-hydrated, occasional use of ibuprofen is safe; the risk is highest for those who are older, dehydrated, or have existing kidney issues.
Should I stop my blood pressure meds if I have a cold?
A minor cold usually doesn’t require stopping meds; ‘Sick Day Rules’ typically apply when you have a high fever, vomiting, or diarrhoea.
Is metformin toxic to the kidneys?
Metformin doesn’t usually cause AKI, but if the kidneys stop working for another reason, metformin can build up in the body and cause a dangerous condition called lactic acidosis.
How long should I pause my meds for?
Usually, you should pause them until you have been eating and drinking normally for at least 24 to 48 hours, but always check with your pharmacist.
Authority Snapshot
This article was written by Dr. Rebecca Fernandez, a UK-trained physician with an MBBS and extensive experience in internal medicine, emergency care, and intensive care. It was reviewed by the MyPatientAdvice clinical team to ensure it meets NHS and NICE [NG148] safety standards for medication-related AKI. This information is provided to help the public understand the safe use of common medications and the importance of clinical monitoring during acute illness.
