ARBs and NSAIDs: losartan, candesartan and ibuprofen explained

ARBs such as losartan and candesartan are taken to lower blood pressure and, depending on the medicine, to help with heart failure. The BNF groups ACE inhibitors and ARBs together in its hyperkalaemia wording, which is why many warnings are shared between them and why ramipril is mentioned in related guides.

NSAIDs include ibuprofen, naproxen, diclofenac and aspirin at pain-relief doses. They are used for pain and inflammation and many are available without a prescription. The NHS ibuprofen page lists headaches, migraines, joint and muscle pain, toothache and period pain among the common reasons for using it.

The combination matters because NSAIDs are often bought off the shelf, so the person managing the blood pressure medicine may not know they are being used.

The BNF interaction lists for losartan and candesartan each include an ibuprofen entry stating that both can increase the risk of hyperkalaemia, and noting that hyperkalaemia is particularly notable when ACE inhibitors or angiotensin-II receptor antagonists are given with spironolactone or eplerenone. The ibuprofen list repeats this for losartan and candesartan.

The NHS losartan page says there are medicines and supplements that may not mix well with it, including some NSAIDs such as ibuprofen, potassium supplements and salt substitutes, spironolactone, other blood pressure medicines, lithium and fluconazole. The NHS candesartan page lists NSAIDs such as ibuprofen and etoricoxib, potassium supplements and salt substitutes, spironolactone, heparin and lithium.

The NHS ibuprofen page, from the other side, says to check the packet or leaflet and to speak to a pharmacist or doctor if you are not sure it is suitable. It lists a heart, liver or kidney condition among reasons ibuprofen may not be suitable.

The BNF entry focuses on hyperkalaemia, a higher than normal potassium level. The kidney connection comes from the NHS ibuprofen page, which lists a kidney problem as a possible serious side effect of ibuprofen on its own, and says the risk of serious side effects is higher if you take a high dose or take it for a long time.

The sources read for this guide do not describe a combined kidney effect for ARBs with NSAIDs beyond those statements. For a wider view of kidney risk with several medicine groups, this site has a separate guide to the NSAID, ACE inhibitor and diuretic triple whammy.

The NHS says paracetamol is a good first choice if you can take it. If you take an ARB, ask a pharmacist before using ibuprofen or other NSAIDs, even for a few days, and be careful with combination cold and flu products that contain an NSAID. Gels and sprays are also NSAIDs, and a pharmacist can say whether they are suitable for you.

If an NSAID has been advised by a clinician, ask whether blood tests of kidney function and potassium are needed. Do not stop your blood pressure medicine because of a painkiller without advice.

• Check packs for ibuprofen, naproxen, diclofenac or aspirin at pain-relief doses.

• Try paracetamol first if it is suitable.

• Report blood in urine, swollen ankles or shortness of breath promptly.

• Avoid potassium supplements and salt substitutes unless advised.

The NHS says to call NHS 111 if you think you are having serious side effects from ibuprofen, and the NHS trimethoprim page describes muscle weakness, an abnormal heartbeat or chest pains as signs of high potassium needing 999 or A&E. Use the same urgency if those symptoms appear while taking an ARB with an NSAID.