From the Guidelines
Cyclobenzaprine is contraindicated in patients with hypersensitivity to the medication, acute recovery phase of myocardial infarction, heart arrhythmias, heart block or conduction disturbances, heart failure, hyperthyroidism, and those taking monoamine oxidase inhibitors (MAOIs) due to its anticholinergic and sedative effects and potential for serious drug interactions 1.
Contraindications and Precautions
The use of cyclobenzaprine is associated with several contraindications and precautions, particularly in certain patient populations. Patients with a history of hypersensitivity to cyclobenzaprine should avoid the medication. Additionally, it is contraindicated in those with acute recovery phase of myocardial infarction, heart arrhythmias, heart block or conduction disturbances, heart failure, and hyperthyroidism due to its potential to worsen these conditions through anticholinergic and sedative effects.
- Concomitant use with monoamine oxidase inhibitors (MAOIs) or within 14 days of their use is contraindicated due to the risk of serotonin syndrome, a potentially life-threatening condition 1.
- Patients with angle-closure glaucoma should not use cyclobenzaprine as it can increase intraocular pressure.
- Elderly patients, especially those with polypharmacy, should use cyclobenzaprine with caution due to its strong anticholinergic effects, which can lead to adverse outcomes such as cognitive decline, falls, and decreased functional status 1.
- Hepatic impairment may also require cautious use, as cyclobenzaprine's metabolism can be affected, leading to enhanced effects and side effects.
- Pregnant women should only use cyclobenzaprine if clearly needed, and nursing mothers should be aware that it may pass into breast milk.
Clinical Considerations
Given the potential for anticholinergic side effects and interactions, the decision to prescribe cyclobenzaprine should be made with careful consideration of the patient's overall clinical profile, including age, comorbidities, and concurrent medications 1. Tapering the medication over 2 to 3 weeks can help prevent withdrawal symptoms in patients who have been on long-term therapy. The potential for drug interactions, particularly with sedatives, anesthetic agents, and MAOIs, underscores the need for vigilant monitoring and management in the perioperative period and beyond.
From the FDA Drug Label
Contraindications Section Hypersensitivity to any component of this product. Concomitant use of monoamine oxidase (MAO) inhibitors or within 14 days after their discontinuation. Hyperpyretic crisis seizures, and deaths have occurred in patients receiving cyclobenzaprine (or structurally similar tricyclic antidepressants) concomitantly with MAO inhibitor drugs. Acute recovery phase of myocardial infarction, and patients with arrhythmias, heart block or conduction disturbances, or congestive heart failure. Hyperthyroidism.
The contraindications for cyclobenzaprine (Flexeril) are:
- Hypersensitivity to any component of the product
- Concomitant use of monoamine oxidase (MAO) inhibitors or within 14 days after their discontinuation
- Acute recovery phase of myocardial infarction
- Patients with arrhythmias, heart block or conduction disturbances, or congestive heart failure
- Hyperthyroidism 2
From the Research
Cyclobenzaprine Contraindications
- Cyclobenzaprine should be used with extreme caution in patients receiving other serotonin-enhancing drugs, as it may cause serotonin syndrome 3.
- There is no direct evidence of contraindications for cyclobenzaprine in the provided studies, except for the interaction with other serotoninergic drugs.
- However, studies on other muscle relaxants and medications suggest that caution should be exercised when prescribing cyclobenzaprine to older adults, as it may be associated with a higher risk of fall compared to some other muscle relaxants 4.
- Cyclobenzaprine overdosage may result in anticholinergic symptomatology, but it does not typically cause coma, seizures, or cardiac toxicity 5.
- While there is no specific study on cyclobenzaprine contraindications in patients with congestive heart failure and concomitant obstructive airway disease, a study on beta-blockers suggests that cardioselective beta-blockers may be safe in patients with obstructive lung diseases 6.
Special Considerations
- Patients taking cyclobenzaprine should be closely monitored for manifestations of serotonin syndrome, especially if they are also taking other proserotoninergic drugs 3.
- Older adults taking cyclobenzaprine should be monitored for the risk of fall, as it may be higher compared to some other muscle relaxants 4.
- In case of cyclobenzaprine overdosage, treatment with physostigmine may be effective in managing anticholinergic symptoms 5.