MAJOR — Use With Caution
🔴 CAUTION — Major interaction between St. Johns Wort and Cyclobenzaprine. Avoid unless under direct medical supervision.
Evidence level: MODERATE
Flexeril has hidden serotonin effects. Combining with St. John's Wort can trigger Serotonin Syndrome.
Cyclobenzaprine has serotonergic properties (structurally similar to tricyclics). Combined serotonin activity increases Serotonin Syndrome risk.
When taking St. Johns Wort with Cyclobenzaprine, watch for early signs of Serotonin Syndrome: restlessness, tremors, rapid heartbeat, flushing, and heavy sweating. Go to the ER immediately if these symptoms appear — do not wait to see if they pass.
Take Cyclobenzaprine as prescribed. St. Johns Wort can typically be taken with a meal at a different time. As a general rule, space botanicals 1-2 hours from prescription medications. St. John's Wort is the most interaction-prone botanical — it affects dozens of drugs via CYP enzyme induction. Always inform your prescriber about herbal supplements.
Higher risk with: high doses, multiple serotonergic agents, older age, recent dose changes, CYP2D6 poor metabolizer status, liver impairment.
Agitation, restlessness, confusion, rapid heartbeat, dilated pupils, muscle twitching or rigidity, heavy sweating, diarrhea, high temperature.
Ask your doctor: "Is there a safer alternative to St. Johns Wort that I can take with Cyclobenzaprine?" Bring a list of ALL supplements and medications you take.
Discuss safer alternatives with your healthcare provider. They can recommend substitutions based on your specific health goals while minimizing interaction risks. Always bring a complete list of everything you take to your appointments.
Flexeril has hidden serotonin effects. Combining with St. John's Wort can trigger Serotonin Syndrome.
Take Cyclobenzaprine as prescribed. St. Johns Wort can typically be taken with a meal at a different time. As a general rule, space botanicals 1-2 hours from prescription medications. St. John's Wort is the most interaction-prone botanical — it affects dozens of drugs via CYP enzyme induction. Always inform your prescriber about herbal supplements.
Agitation, restlessness, confusion, rapid heartbeat, dilated pupils, muscle twitching or rigidity, heavy sweating, diarrhea, high temperature.
Discuss safer alternatives with your healthcare provider. They can recommend substitutions based on your specific health goals while minimizing interaction risks. Always bring a complete list of everything you take to your appointments.
Ask your doctor: "Is there a safer alternative to St. Johns Wort that I can take with Cyclobenzaprine?" Bring a list of ALL supplements and medications you take.
Or browse the full interaction database (121,000+ pairs).