FDA clears a supplement to the empagliflozin-linagliptin-metformin combination

What is worth restating for a nephrology readership is how this combination behaves as kidney function falls, because the three components have different constraints. Empagliflozin is now used for kidney protection well below the glycaemic thresholds it was first approved at, and its glucose-lowering effect diminishes as GFR falls while its kidney benefit does not. Metformin is the component that limits the combination: it requires review of dose as eGFR falls and is contraindicated below the accepted threshold. Linagliptin is cleared largely by the biliary route and needs no dose adjustment in kidney impairment.

The practical consequence is that a fixed-dose combination is convenient until it is not. A patient whose eGFR falls to the point where metformin must be reduced or stopped cannot have that done inside a combination tablet, and the component you most want to keep, the SGLT2 inhibitor, is the one that gets discontinued along with everything else. In India, where fixed-dose combinations are widely prescribed and often continued without review, that is the failure mode worth watching for.

• Check which components a fixed-dose combination contains before assuming a patient is or is not on an SGLT2 inhibitor
• Review the metformin component against current eGFR at every visit, and unbundle the combination when it needs reducing
• Continue the SGLT2 inhibitor for kidney protection when the combination is broken up, rather than stopping everything together
• Remember linagliptin needs no dose adjustment in kidney impairment, unlike most of its class
• Note this is a US regulatory action; Indian availability and labelling follow CDSCO