Zopiclone and eszopiclone (Lunesta) are the same compound — eszopiclone is the purified active stereoisomer of zopiclone. This 2026 guide covers the GABA mechanism, correct dosage by strength, why the metallic taste occurs, dependence and withdrawal risks, the next-day driving warning, complex sleep behaviour FDA boxed warning, and a full 4-Z-drug comparison table.

Zopiclone's side effects are predictable and mostly manageable — but patients deserve to know exactly what to expect. The bitter metallic taste affects up to 30 percent of users. Morning drowsiness reflects the 5 to 6 hour half-life. Complex sleep behaviours carry an FDA boxed warning. This complete guide covers every side effect with frequency ratings and specific management tips, plus the serious warning signs that require immediate medical advice.