From the FDA Drug Label
The safe use of chlorzoxazone has not been established with respect to the possible adverse effects upon fetal development Therefore, it should be used in women of childbearing potential only when, in the judgement of the physician, the potential benefits outweigh the possible risks.
- Chlorzoxazone use in pregnant women is not established as safe with respect to potential adverse effects on fetal development.
- The decision to use chlorzoxazone in pregnant women should be made by a physician, weighing the potential benefits against the possible risks 1.
From the Research
Chlorzoxazone should not be used during pregnancy unless absolutely necessary and under close medical supervision. The safety of chlorzoxazone in pregnant women has not been well established, and potential risks to the fetus are not fully understood. Although there is limited direct evidence on chlorzoxazone, studies on similar muscle relaxants like cyclobenzaprine suggest potential risks, such as increased odds of certain birth defects 2. When considering muscle relaxation during pregnancy, healthcare providers typically recommend alternative treatments with better safety profiles first. Non-pharmacological approaches such as physical therapy, gentle stretching, heat therapy, and rest should be tried before considering medication. If medication becomes necessary, other muscle relaxants with more data in pregnancy might be considered. The decision to use chlorzoxazone during pregnancy should be made after careful consideration of the potential benefits versus risks, involving a thorough discussion between the patient and their healthcare provider about individual circumstances and medical needs. It's also worth noting that the use of any medication during pregnancy should be approached with caution, as seen with the controversy surrounding nicotine replacement therapy 3, and the potential effects of non-steroidal anti-inflammatory drugs (NSAIDs) on the fetus 4. However, the most recent and relevant study to consider in this context is the one on cyclobenzaprine, which, although not directly about chlorzoxazone, provides insight into the potential risks associated with muscle relaxants during pregnancy 2.