How are medicines adjusted to avoid worsening AKI? 

Medicines are adjusted during acute kidney injury (AKI) by temporarily pausing drugs that reduce blood flow to the renal system or those that accumulate to dangerous levels when filtration slows. This process, often referred to as ‘Sick Day Rules’, provides the kidneys with a ‘medication holiday’ to recover. By stopping specific blood pressure tablets and anti-inflammatories, clinicians prevent further drop in the internal kidney pressure required for waste filtration. 

What We will cover in this Article 

• The clinical rationale for pausing medications during an acute kidney event 

• Understanding the ‘DAMN’ acronym for high-risk renal medications 

• How dosage adjustments prevent ‘renally cleared’ drugs from reaching toxic levels 

• The role of ‘Sick Day Rules’ in primary care and hospital settings 

• When it is safe to restart medications after kidney function improves 

• Differentiating between nephrotoxic drugs and those that require dose adjustment 

• UK clinical protocols for pharmaceutical safety during kidney distress 

The process of medication adjustment in AKI 

Medicines are adjusted by identifying ‘nephrotoxic’ drugs that can directly harm the kidneys or alter the blood pressure inside the organ’s filters. Clinicians also review ‘renally cleared’ medications, which are those primarily removed from the body by the kidneys. If these are not adjusted, they can build up in the bloodstream, leading to side effects or toxicity. This dual approach ensures the kidneys are protected while keeping the patient safe from drug accumulation. 

When a patient is identified as having AKI, a pharmacist or doctor performs a ‘clinical medication review’. They look for drugs that might be the ‘trigger’ for the injury or those that make it harder for the kidneys to heal. In the UK, this often involves a temporary ‘pause’ rather than a permanent stop. This is because many of these medications, such as ACE inhibitors for heart health, are vital in the long term but dangerous during an acute episode of dehydration or infection. 

• Pausing: Stopping the drug entirely for a few days until creatinine levels stabilise. 

• Dose Reduction: Lowering the amount of a drug (like certain antibiotics) to match the kidney’s current filtration rate. 

• Substitution: Swapping a kidney-stressing drug for a safer alternative, such as using paracetamol instead of ibuprofen. 

• Monitoring: Using ‘therapeutic drug monitoring’ (blood tests) to check the levels of specific medications in the blood. 

The DAMN acronym and ‘Sick Day Rules’ 

In UK clinical practice, the ‘DAMN’ acronym is a common tool used to remember which high-risk drugs should be paused during an illness that causes dehydration or AKI. This includes Diuretics, ACE inhibitors (and ARBs), Metformin, and NSAIDs. Stopping these medications prevents the ‘triple whammy’ effect, where multiple drugs combined with dehydration cause a rapid and severe drop in the kidney’s ability to filter blood. 

‘Sick Day Rules’ are instructions given to patients who take these medications. They are advised to temporarily stop taking them if they develop a fever, vomiting, or diarrhoea. This is a proactive safety measure. For example, NSAIDs like ibuprofen work by narrowing the blood vessels that enter the kidney; during an illness, this can ‘starve’ the kidney of blood, leading to acute injury. 

Drug Group	Examples	Adjustment Action	Why it is Adjusted
Diuretics	Furosemide, Bendroflumethiazide	Pause	Prevents worsening of dehydration and low blood pressure.
ACE Inhibitors / ARBs	Ramipril, Losartan, Lisinopril	Pause	Maintains the internal pressure the kidneys need to filter waste.
Metformin	Diabetes medication	Pause	Prevents the build-up of lactic acid if kidney function is low.
NSAIDs	Ibuprofen, Naproxen, Diclofenac	Stop	Prevents the constriction of blood vessels inside the kidney.
SGLT2 Inhibitors	Dapagliflozin, Empagliflozin	Pause	Reduces the risk of dehydration-related complications during illness.

Causes and triggers for medicine adjustment 

The need for adjustment is usually triggered by an ‘acute insult’ to the body. This could be a physical illness, a new prescription, or a change in a patient’s environment that affects their hydration levels. 

• Dehydration: Caused by heatwaves, vomiting, or diarrhoea, making the kidneys more vulnerable to drug side effects. 

• Sepsis: A severe infection that drops blood pressure, requiring an immediate pause of ‘blood pressure lowering’ drugs. 

• Contrast Dye: Used in some hospital scans, which requires certain drugs like Metformin to be paused for 48 hours. 

• New Prescriptions: Starting a ‘water pill’ (diuretic) without checking baseline kidney function can trigger an injury. 

Differentiation: Nephrotoxic vs Renally Cleared Drugs 

It is important to distinguish between drugs that cause kidney damage and those that are simply affected by it. This distinction determines whether a drug is stopped or just reduced in dose. 

Category	Definition	Action Taken	Clinical Example
Nephrotoxic	Drugs that can actively injure the kidney tissue or blood flow.	Usually stopped or avoided during an acute injury.	Ibuprofen (NSAIDs)
Renally Cleared	Drugs that are safe for the kidney but are removed by it.	Usually dose-reduced to prevent toxicity.	Certain antibiotics (e.g., Gentamicin)

To Summarise 

Medicines are adjusted during AKI to prevent further renal stress and to protect the patient from drug toxicity. By following ‘Sick Day Rules’ and pausing high-risk medications like NSAIDs and ACE inhibitors, clinicians allow the kidneys to recover their filtration capacity. These adjustments are typically temporary, and medications are safely restarted once blood tests confirm that the kidney function has returned to its normal baseline. 

If you experience severe, sudden, or worsening symptoms, call 999 immediately. 

Authority Snapshot 

This article was written by Dr. Rebecca Fernandez, a UK-trained physician with an MBBS and extensive experience in internal medicine, emergency medicine, and intensive care. It was reviewed by the MyPatientAdvice clinical team to ensure it follows the latest NHS and NICE guidelines on medication safety and acute kidney injury management. Our goal is to provide the public with clear, factual, and medically safe information to help them understand how their medications are managed during illness to protect their long-term renal health.