The NSAID, ACE inhibitor and diuretic "triple whammy" and your kidneys

Clinicians use this phrase for the combination of an NSAID, an ACE inhibitor or similar blood pressure medicine, and a diuretic. Each hits a different part of the way the kidney keeps its filters supplied with blood, and the three together can leave the kidney short of flow when it is already under stress.

The NHS acute kidney injury page lists NSAIDs, ACE inhibitors and diuretics as medicines that can increase the risk, and says long-term use is particularly concerning. Kidney Research UK similarly says NSAIDs such as ibuprofen, naproxen and diclofenac and drugs for high blood pressure can contribute.

NSAIDs reduce the chemicals that keep the small blood vessels feeding the kidney open. ACE inhibitors, and the related ARBs, widen the vessels leaving the filter, which lowers pressure inside it. Diuretics reduce the volume of fluid in the body. If all three act at once, the filter can lose both pressure and blood supply.

In a healthy, well-hydrated person the kidney can usually compensate. When there is vomiting, diarrhoea, fever or poor intake, the compensation fails more easily, which is why the phrase is most often applied to someone who has an infection and is unwell.

People with existing kidney disease, heart failure or diabetes, older adults and those on several blood pressure tablets are more exposed. The NHS says kidney injury can follow infections, dehydration, low blood pressure or blood loss, and that medicines add to the risk. Our chronic kidney disease guide covers longer-term kidney problems.

Over-the-counter use matters. Ibuprofen and similar products are sold freely, so a person may add an NSAID to a stable prescription list without anyone noticing. The NHS ibuprofen page says it may not be suitable if you have a heart, liver or kidney condition, and lists blood pressure medicines among those to check.

The NHS lists passing much less urine than usual, thirst, nausea, swollen limbs, fatigue, dizziness, confusion and breathlessness. Some people have no early symptoms, which is why a blood test is how it is usually found. The NHS says to contact NHS 111 or request an urgent GP appointment if you suspect it.

Kidney Research UK adds that it is important to tell your doctor which medicines you have been taking, since this helps identify a cause. Many cases resolve without lasting damage, though some progress to chronic kidney disease later.

• Passing noticeably less urine.

• Persistent thirst, nausea or dizziness.

• Swelling in the ankles or hands.

• New confusion or breathlessness.

The NHS advises staying hydrated so urine remains pale, particularly in hot weather or illness, speaking to a doctor before starting new medicines or supplements, and knowing the warning signs. Before you take an anti-inflammatory painkiller, ask a pharmacist if it is suitable with your blood pressure tablets; paracetamol is often discussed as an alternative for pain.

Do not stop a prescribed ACE inhibitor or diuretic on your own initiative when ill. Some people have a written plan from their GP or kidney team for pausing certain tablets during dehydrating illness; ask whether one is suitable for you.

Gels applied to the skin deliver much less drug to the blood than tablets, but the NHS pages we read do not give a rule, so a pharmacist should advise if you have kidney problems. The same applies to aspirin taken for pain, which the NHS ramipril page treats differently from the 75mg daily low dose.