Ibuprofen × Metamizole sodium

Metamizole is a pyrazolone with central analgesic and spasmolytic action, not a classic NSAID, so the ban on stacking NSAIDs does not apply and direct gastric damage is lower. What it does bring is a risk of its own: the European review summarised by AEMPS confirmed agranulocytosis as a rare, unpredictable reaction and recommended short courses at the lowest dose. The pair is not metabolically neutral either, since metamizole induces CYP2B6 and CYP3A4.

The signal not to miss belongs to metamizole: returning fever, sore throat, mouth ulcers, an infection that will not clear. Any of these during treatment means stopping it and checking a full blood count. From ibuprofen, the digestive and renal risks continue unchanged by the pairing.

They can be alternated in severe acute pain when one alone is not enough, over a few days. Metamizole is not continued unmonitored and is stopped at any new fever or infection. In patients on bupropion, methadone, valproate, ciclosporin, tacrolimus or sertraline, metamizole lowers their levels and another analgesic is the better choice.