Metrazene is a drug that boosts metabolism.
Metrazene can be used with lethozine to reduce the physiological response in the body of a non-Trill individual who has been joined with a Trill symbiont. (TNG episode: "The Host", ST - Divided We Fall comic: "All Fall Down", ST reference: The Starfleet Survival Guide)
In 2376, Julian Bashir used metrazene, lethozine and metraprovoline when Ezri Dax started to reject the Dax symbiont after an encounter with the "cathedral artifact" in the Gamma Quadrant. (DS9 - Mission Gamma novel: Cathedral)