Related Clues:

• Cocaine, for one
• Pain reliever
• Morphine, e.g.
• Sense-dulling drug
• It may induce relaxation
• Sedative
• Drug
• Mind boggler
• It can knock you out
• Potent drug
• Lethargy inducer
• Sedative drug
• Endorphin, e.g.
• Drug that dulls the brain
• Drug from poppies