Drug induced stuttering: pharmacovigilance data

Background: Stuttering is a speech disorder characterized by poor fluency of speech despite the speech production organs being normal. Numerous factors contribute to stuttering, and it may also be an iatrogenic effect of certain drugs. The aim of this study was to investigate the association between stuttering and drug exposure.Research design and methods: We investigated the association between drugs and stuttering. We analyzed reports in the World Health Organization global individual case safety reports database (Vigibase) up to 31 May 2020 with the MedDRA lower level terms 'stutter' and 'stuttering.' The association between a drug and the occurrence of the adverse drug reaction was estimated by disproportionality analysis. Reporting odds ratios (ROR) were calculated with 95% confidence intervals.Results: In total, 724 notifications were identified using the MedDRA terms selected. The main drugs implicated were methylphenidate (ROR = 19.58; 95% CI: 13.3-28.8), topiramate (ROR = 12.5; 95% CI: 7.1-22.1), olanzapine (ROR = 12; 95% CI: 8-17.9) and golimumab (ROR = 10.2; 95% CI: 5.5-19.1).Conclusions: When stuttering occurs in a patient treated by drugs affecting neurotransmission, a drug-induced origin of the stutter should be considered.