The Most Common Side Effect: Bitter or Metallic Taste
When taking zopiclone, a significant number of users, around 10%, experience a distinctive and unpleasant bitter or metallic taste. This taste disturbance, known medically as dysgeusia, can linger for hours after waking and is considered the most frequently reported adverse effect of the medication. The phenomenon is likely caused by the drug's metabolites, which are excreted into saliva. While it is often a nuisance, it is not a sign of a serious health problem. Healthcare providers often advise patients about this side effect to set proper expectations and prevent undue alarm.
Managing the Unpleasant Taste
To help mitigate the bitter taste associated with zopiclone, patients can try several strategies:
- Sip water and keep a glass by the bed.
- Use a mouthwash before going to bed, specifically one recommended for dry mouth.
- Suck on sugarless mints or gum the following morning.
- Brush your teeth and tongue thoroughly after waking.
Other Common Zopiclone Side Effects
Beyond the unique taste disturbance, zopiclone can cause other common side effects that are often linked to its sedative properties. These effects are typically mild and temporary, diminishing as the body adjusts to the medication.
- Daytime Drowsiness: Given that zopiclone is a hypnotic, feeling sleepy, tired, or hungover the next day is a frequent occurrence. This can impair the ability to perform tasks requiring alertness, such as driving or operating heavy machinery.
- Dry Mouth: Experiencing a dry mouth, known as xerostomia, is a common complaint that often accompanies the bitter taste. This can lead to discomfort and, if persistent, can affect oral health.
- Headache: Some patients report headaches after taking zopiclone.
- Dizziness: Feeling dizzy or lightheaded can occur, which increases the risk of falls, particularly in elderly individuals.
- Gastrointestinal Issues: Nausea, vomiting, indigestion, and diarrhea or constipation are also reported.
Comparison of Z-Drugs: Zopiclone vs. Zolpidem vs. Eszopiclone
Zopiclone belongs to a class of medications called "Z-drugs," which also includes zolpidem and eszopiclone (the active isomer of zopiclone). While all are used for insomnia, they have different side effect profiles.
| Feature | Zopiclone | Zolpidem (Ambien) | Eszopiclone (Lunesta) |
|---|---|---|---|
| Most Common Side Effect | Bitter or metallic taste | Drowsiness, headaches, dizziness | Bitter or metallic taste |
| Memory-Related Effects | Can cause anterograde amnesia | Can cause memory loss and sleepwalking | Can cause memory loss |
| Next-Day Impairment | Possible hangover effects | Significant risk of impairment | Less next-day impairment observed in some studies |
| Addiction Potential | Potential for dependence, especially with prolonged use | Potential for abuse and dependence | Potential for abuse and dependence |
Less Common and Serious Side Effects
Although rare, some side effects of zopiclone are more serious and require immediate medical attention. These risks highlight the importance of using the medication strictly as prescribed by a doctor.
- Complex Sleep Behaviors: Some people may perform activities such as sleepwalking, sleep-driving, or preparing food while not fully awake and have no memory of the event later. This risk increases with higher doses or with alcohol.
- Anterograde Amnesia: Temporary memory loss for events that occur after taking the medication can happen, especially if sleep is interrupted.
- Psychiatric and Mood Changes: Rarely, zopiclone can cause confusion, irritability, aggression, or hallucinations. Pre-existing depression may be exacerbated.
- Paradoxical Effects: Instead of calming the user, the drug may have the opposite effect, causing agitation, restlessness, or nightmares.
- Severe Allergic Reactions: Signs of an allergic reaction, such as swelling of the face, tongue, or throat, or difficulty breathing, require emergency medical care.
Important Considerations and Safe Use
Zopiclone should always be used with caution and under a doctor's supervision. It is generally intended for short-term use, typically for 2 to 4 weeks, to minimize the risk of developing tolerance and dependence. Abrupt discontinuation, particularly after prolonged use, can lead to withdrawal symptoms like anxiety, tremors, and rebound insomnia.
Patients should never take zopiclone with alcohol or other CNS depressants, as this can significantly increase the risk of severe drowsiness, breathing difficulties, and even overdose. To avoid next-day impairment, a full 7-8 hours of sleep is necessary after taking the medication, and individuals should be careful when driving or operating machinery until they know how they are affected.
For more detailed information, consult the National Health Service (NHS) guide on zopiclone: Side effects of zopiclone - NHS.
Conclusion
While the most common side effect of zopiclone is a persistent bitter or metallic taste, it is crucial to be aware of the full range of potential side effects, from common issues like next-day drowsiness to rarer but more serious reactions like complex sleep behaviors. By adhering to prescribed dosages and duration, avoiding alcohol, and understanding both the minor and major risks, patients can use zopiclone more safely and effectively for the short-term management of insomnia. Any persistent or concerning side effects should always be discussed with a healthcare professional.
