Why should SSRIs never be mixed with St. John's Wort, MAOIs, or any other antidepressants?

Why should SSRIs never be mixed with St. John's Wort, MAOIs, or any other antidepressants?

• A. Improved efficacy
• B. No risk
• C. Serotonin syndrome risk due to interactions
• D. Severe sedation risk

Answer: (C)

Mixing SSRIs with other substances that boost serotonin raises the risk of serotonin syndrome, a potentially life‑threatening condition. SSRIs increase serotonin by blocking its reuptake; MAOIs block the enzyme that breaks down serotonin, so combining them allows serotonin levels to rise too much. St. John’s Wort contains active compounds that increase serotonin activity and can also affect drug metabolism, which can raise levels of antidepressants in the body. When these serotonergic effects stack, symptoms can appear—from agitation and rapid heart rate to confusion, high fever, tremor, and in severe cases seizures. That danger is why this combination is avoided, rather than there being any improved efficacy or no risk. Sedation isn’t the primary issue here, though some agents can cause sedation independently.

Mixing SSRIs with other substances that boost serotonin raises the risk of serotonin syndrome, a potentially life‑threatening condition. SSRIs increase serotonin by blocking its reuptake; MAOIs block the enzyme that breaks down serotonin, so combining them allows serotonin levels to rise too much. St. John’s Wort contains active compounds that increase serotonin activity and can also affect drug metabolism, which can raise levels of antidepressants in the body. When these serotonergic effects stack, symptoms can appear—from agitation and rapid heart rate to confusion, high fever, tremor, and in severe cases seizures. That danger is why this combination is avoided, rather than there being any improved efficacy or no risk. Sedation isn’t the primary issue here, though some agents can cause sedation independently.