Serotonin Syndrome Risk with Lamotrigine and Zonisamide

Medications That Contribute to Serotonin Syndrome

Opioids, particularly tramadol, meperidine, methadone, and fentanyl, when combined with antidepressants, contribute to serotonin syndrome, according to the American College of Medical Toxicology 1, 2, 3.
Triptans combined with SSRIs or SNRIs pose a risk of serotonin syndrome, though the risk is considered low, as noted by the Mayo Clinic 4, 5.
Ergotamine with opioids poses a risk of serotonin syndrome in the perioperative setting, as reported by the Mayo Clinic 4, 5.
Over-the-counter medications, including dextromethorphan, St. John's Wort, and L-tryptophan supplements, when combined with prescription serotonergic agents, contribute to serotonin syndrome, according to the American Association of Clinical Toxicology 2, 3.

If prescribing lamotrigine alongside SSRIs, SNRIs, MAOIs, or other serotonergic medications, educate patients about serotonin syndrome symptoms, such as confusion, agitation, muscle twitching, fever, rapid heart rate, and profuse sweating, as recommended by the American College of Medical Toxicology 2, 3.
Symptoms typically emerge within 24-48 hours after combining medications or dose increases, making this the highest-risk monitoring period, according to the American Association of Clinical Toxicology 2, 3, 6.
Myoclonus (muscle twitching) occurs in 57% of serotonin syndrome cases and is the most common finding, while clonus and hyperreflexia are highly diagnostic, as noted by the American College of Medical Toxicology 6, 3.

Immediately discontinue all serotonergic agents, including lamotrigine, if suspected to be contributing to serotonin syndrome, as recommended by the American College of Medical Toxicology 2, 6, 3.
Provide supportive care with benzodiazepines for agitation, IV fluids, external cooling for hyperthermia, and continuous cardiac monitoring, according to the American Association of Clinical Toxicology 2, 6, 3.
Consider cyproheptadine (a serotonin antagonist) in severe cases, as approximately 25% of patients require ICU admission with mechanical ventilation, as noted by the American College of Medical Toxicology 6.
The mortality rate for severe serotonin syndrome is approximately 11%, with complications including rhabdomyolysis, renal failure, seizures, and disseminated intravascular coagulopathy, according to the American Association of Clinical Toxicology 6, 3.

Tramadol inhibits serotonin reuptake in addition to its opioid activity, classifying it as a weak SNRI, according to the American College of Rheumatology, based on evidence from Annals of the Rheumatic Diseases 7 and Mayo Clinic Proceedings 8
Tramadol is specifically identified among opioids with serotonin reuptake inhibitory activity that increase serotonin syndrome risk when combined with medications that increase serotonin levels, as stated by the Mayo Clinic 8

The combination of tramadol with other serotonergic medications, such as SSRIs, SNRIs, TCAs, MAOIs, and triptans, increases the risk of serotonin syndrome, as warned by the FDA and supported by evidence from Annals of the Rheumatic Diseases 7

Underestimating risk in depression/anxiety patients who take multiple serotonergic medications compounds the risk of serotonin syndrome, as noted by the European League Against Rheumatism (EULAR) 7

The Mayo Clinic perioperative guidelines 8 and EULAR fibromyalgia recommendations 7 provide high-quality directive evidence, corroborating the risk of serotonin syndrome with tramadol use in clinical contexts.