Aims Antipsychotics and lithium are widely used in psychiatry, particularly in schizophrenia and bipolar disorders. Recently, some cases of somnambulism or sleep‐related eating disorder (SRED) have been reported in patients treated with these drugs. This study investigated the risk of reporting somnambulism or SRED associated with the use of antipsychotics and lithium. Methods The World Health Organization pharmacovigilance database (VigiBase), comprising >18 million adverse events, was queried. All somnambulism or SRED reports related to antipsychotics or lithium were identified. The association between antipsychotics or lithium and somnambulism or SRED was computed using the proportional reporting ratio (PRR) and information component. Results Among the 5784 cases reporting somnambulism or SRED, 508 suspected at least 1 antipsychotic or lithium. Most patients were aged 18–64 years (62.0%), and 37.0% were men. In most cases (77.6%), antipsychotic or lithium were the only drug class involved, and 53.3% of cases suspected quetiapine. Somnambulism was reported in 88.6% of cases and SRED in 18.1%. A significant association was found for second‐generation antipsychotics (PRR 3.44, 95% confidence interval 3.13) and lithium (PRR 2.03, [1.22; 3.37]), but not for first‐generation antipsychotics (PRR 0.99, [0.68; 1.44]). Conclusions We found a significant signal of somnambulism or SRED related to second‐generation antipsychotics and lithium. While case reports mentioned mostly quetiapine and olanzapine, almost all second‐generation antipsychotics were associated with somnambulism or SRED.

Few data are available on the clinical impact of drug–drug interactions (DDIs). Most of the studies are limited to the analysis of exposure to potential DDI or the targeted impact of the combination of a few drugs or therapeutic classes. The analysis of adverse drug reaction (ADR) reports could be a mean to study generally the adverse effects identified due to a DDI. Our objective was to describe the characteristics of ADRs resulting from DDIs reported to the French Pharmacovigilance system and to identify the drugs most often implicated in these ADRs. Considering all ADR reports from January 01, 2012, to December 31, 2016, we identified all cases of ADR resulting from a DDI (DDI-ADRs). We then described these in terms of patients’ characteristics, ADR seriousness, drugs involved (two or more per case), and ADR type. Of the 4,027 reports relating to DDI-ADRs, 3,303 were related to serious ADRs. Patients with serious DDI-ADRs had a median age of 76 years (interquartile range: 63–84); 53% were male. Of all serious DDI-ADRs, 11% were life-threatening and 8% fatal. In 36% of cases, the DDI causing the ADR involved at least three drugs. Overall, 8,424 different drugs were mentioned in the 3,303 serious DDI-ADRs considered. Altogether, drugs from the “antithrombotic agents” subgroup were incriminated in 34% of serious DDI-ADRs. Antidepressants were the second most represented therapeutic/pharmacological subgroup (5% of serious DDI-ADRs). Among the 3,843 ADR types reported in the 3,303 serious DDI-ADRs considered, the most frequently represented were hemorrhage (40% clinical hemorrhage; 6% biological hemorrhage), renal failure (8%), pharmacokinetic alteration (5%), and cardiac arrhythmias (4%). Hemorrhagic accidents are still an important part of serious ADRs resulting from DDIs reported in France. The other clinical consequences of DDIs seem less well identified by pharmacovigilance. Moreover, more than one-third of serious DDI-ADRs involved at least three drugs.

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