Lithium - Benzocaine, Dextromethorphan Interaction

Interaction Details

Benzocaine, Dextromethorphan is classified as belonging to the following category: Serotonergic Drugs

Theoretically, taking lithium supplements with serotonergic drugs might both mask and increase the risk of serotonin syndrome.
In a case report, a 67-year-old female with depression and bipolar disorder using lithium in combination with selective serotonin reuptake inhibitors (SSRIs) and other medications developed serotonin syndrome with symptoms of deep tendon hyperreflexia, muscle rigidity, tremor, and hyperthermia. However, agitation, one classical symptom of serotonin syndrome, was lacking. This was thought to be due to masking by lithium toxicity. Lithium can increase serotonin levels, thus, combining serotonergic drugs with lithium might increase the risk of serotonergic side effects including serotonin syndrome and cerebral vasoconstrictive disorders. It is unclear if this interaction would occur with the smaller doses found in lithium supplements.

Interaction Rating

Likelihood of Occurrence

Interaction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.

References

• Martindale W. Martindale the Extra Pharmacopoeia. Pharmaceutical Press, 1999.
• McEvoy GK, ed. AHFS Drug Information. Bethesda, MD: American Society of Health-System Pharmacists, 1998.
• Landa E, Wagner S, Makkar A, Liu A, Jung D. An atypical presentation of serotonin syndrome. Cureus. 2021;13(2):e13377.

Lithium - More Interactions

Lithium interacts with 511 drugs

Interaction Rating Key

These severity listings are for informational use only. Never start, stop or otherwise change your therapy before speaking with your provider.