Taking lithium in addition to other psychiatric medications may lower the risk of hyponatremia (low blood sodium) but increase the risk of conditions such as tremor, ataxia (poor muscle control), and myoclonus (twitching or spasms), according to a
study in the
Journal of Psychopharmacology.
Why It’s Relevant
Lithium is often prescribed in combination with other psychiatric medications such as antidepressants and antipsychotics, and patients treated with lithium often receive a greater number of medications compared with patients not treated with lithium. Real-world data on how lithium interacts with other medications can help optimize polypharmacy strategies.
By the Numbers
- Study investigators analyzed data from 8,609 adults who took psychiatric medications and were treated in psychiatric hospitals in Germany, Austria, and Switzerland between 1993 and 2015.
- Patients who took lithium alongside other psychiatric medications (n=720) were 24 times less likely to report hyponatremia than those who didn’t take lithium. They were also less likely to report dyskinesia and weight gain.
- However, those who took lithium were also twice as likely to report Parkinson’s symptoms or delirium, nearly three times more likely to report ataxia or myoclonus, and more than four times as likely to report tremor.
- Adults who took lithium were also 26 times more likely to report drug-drug interactions leading to intoxication.
The Other Side
Some adverse drug reactions, such as weight gain, may be perceived as less burdensome or may develop gradually and therefore be underreported in hospital data. The patients on lithium were also older and took more medications on average. Further, although the results reflect actual medication use and not just prescriptions, diagnostic patterns, available medications, and hospital practices changed over the 23-year study period, which can lead to confounding.
Takeaway Message
“When part of the therapeutic regimen, lithium may possess a positive profile regarding drug-induced hyponatremia or weight gain,” the researchers wrote. “On the other hand, lithium-treated patients may be at higher risk of neurotoxicity, so that regular monitoring is recommendable particularly in patients with antipsychotic polypharmacy combined with lithium.”
Related Information
Source
Waldemar Greil, et al. Adverse drug reactions associated with psychotropic medications combined with versus without lithium: a case/control pharmacovigilance analysis. Journal of Psychopharmacology. Published October 13, 2026. doi:10.1177/02698811261488471
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