From the Guidelines
There is no direct evidence of a significant interaction between zopiclone and cyclobenzaprine in the provided studies, but caution is advised due to their potential additive sedative effects as central nervous system (CNS) depressants. Both medications can cause drowsiness, impaired coordination, and increased risk of falls, especially in older adults 1. Zopiclone is a non-benzodiazepine sedative-hypnotic used for insomnia, while cyclobenzaprine is a muscle relaxant typically prescribed for muscle spasms.
Key Considerations
- The combination of zopiclone and cyclobenzaprine may increase the risk of excessive drowsiness, impaired coordination, dizziness, confusion, and respiratory depression.
- If both medications must be taken, reduced dosages, increased time between taking each medication, or alternative treatments might be recommended by a doctor.
- It is essential to inform all healthcare providers about all medications being taken, including over-the-counter drugs and supplements, to avoid potentially harmful drug interactions.
Mechanism of Action
- Both zopiclone and cyclobenzaprine enhance the effects of the inhibitory neurotransmitter GABA in the brain, though through different mechanisms.
- This enhancement can lead to additive sedative effects, increasing the risk of adverse events.
Clinical Implications
- The potential risks and benefits of combining zopiclone and cyclobenzaprine should be carefully weighed, considering the individual patient's health status and medical history.
- Alternative treatments or adjustments to the treatment regimen may be necessary to minimize the risk of adverse interactions 1.
From the Research
Interaction between Zopiclone and Cyclobenzaprine
- There is no direct evidence of an interaction between zopiclone and cyclobenzaprine in the provided studies 2, 3, 4, 5, 6.
- However, it is known that zopiclone is a cyclopyrrolone hypnosedative that potentiates gamma-aminobutyric acid-mediated neuronal inhibition 4, 5.
- Cyclobenzaprine, on the other hand, is a tricyclic dimethylpropanamine skeletal muscle relaxant that has been shown to exhibit non-competitive antagonism at the histamine H1 receptor, which may contribute to its sedative effects 3.
- Zopiclone has been shown to have a low risk of significant rebound insomnia and withdrawal reactions, and its tolerability profile is similar to that of placebo 4.
- The pharmacokinetic and pharmacodynamic interactions of zopiclone with other drugs, such as cytochrome P450 inducers and inhibitors, have been studied, but there is no specific information on its interaction with cyclobenzaprine 2.
- Given the sedative effects of both zopiclone and cyclobenzaprine, it is possible that their concurrent use may enhance sedation, but this is speculative and requires further study.
Mechanism of Action
- Zopiclone binds to the benzodiazepine receptor complex, or to a site closely linked to this complex, and exhibits anticonvulsant, muscle relaxant, and anxiolytic properties in animals 5.
- Cyclobenzaprine's mechanism of action is not fully understood, but it is thought to mediate its effects centrally via inhibition of tonic somatic motor function, likely through modulation of noradrenergic and serotonergic systems 3.
Clinical Implications
- The use of zopiclone and cyclobenzaprine together may require careful consideration of their potential sedative effects, and patients should be monitored for excessive sedation or other adverse effects.
- Further studies are needed to fully understand the interaction between zopiclone and cyclobenzaprine and to determine their safety and efficacy when used concurrently.