Endomethalamine is a drug that can be used to lower the amounts of isoboramine in a Trill symbiont.

In 2376, Julian Bashir had Krissten Richter inject the Dax symbiont, temporarily unjoined from Ezri Dax, with ten ccs of endomethalamine to counteract the high amount of isoboramine that was causing distress to the symbiont. (DS9 - Mission Gamma novel: Cathedral)