Communion is a deeply sinister drug, and all the more so for being legal. In a future of ecological catastrophe and over-population, that government has sanctioned mass suicides. They even provide the drug for them, at no charge: Communion.
The drug has two parts: a neurotoxin absorbed through your saliva, and a muscle relaxant that kicks in more slowly, killing you softly and painlessly.
Unless, of course, your mouth is dry from the excitement of your impending end, in which case the neurotoxin won’t work and the muscle relaxant will, killing you, but only after a minute or so of anguish in which time you are fully conscious but unable to move.