Zopiclone, a sedative for insomnia, may cause dizziness, dry mouth, and a bitter aftertaste. Some users experience drowsiness, headaches, or digestive issues like nausea. Long-term use raises the risk of dependency and tolerance, making withdrawal difficult. Severe side effects include memory loss, confusion, mood swings, or allergic reactions (rash, swelling). Rarely, it may trigger sleepwalking or hallucinations. Avoid alcohol and consult a doctor if side effects worsen. Use short-term only to reduce risks.