Halcion 0.125mg is an FDA-approved medication for insomnia. Halcion is available as a generic medication. FDA approval means the medication has undergone rigorous testing by the U.S. Food and Drug Administration to demonstrate its effectiveness and safety for a particular use. This medication helps you sleep better, and the tablets start working within 30 min after taking. but it should only be used for a short period of time. In addition to sleepiness, this medication can cause side effects like headaches and dizziness. Like other benzodiazepines, Halcion also has other effects and interactions with other medications.