Methylphenidate and stuttering

: Methylphenidate (MPH) is a piperidine similar to amphetamines, and is indicated for attention deficit hyperactivity disorder. Studies concerning stuttering occurring with MPH are contradictory. We investigated the association between MPH and stuttering. We analysed reports in the World Health Organization global individual case safety reports database, Vigibase, up to 31 December 2018, with the MedDRA preferred term “dysphemia” and the lower level terms “stutter” and “stuttering”. The association between exposure to MPH and occurrence of the adverse drug reaction was estimated by disproportionality analysis. Reporting odds ratios (RORs) were calculated with 95% confidence intervals (CIs). In total, 2975 cases of dysphemia were reported, of which 46 reports were associated with MPH. For the Preferred Term “dysphemia”, the ROR was 7.3 (95% CI: 5.4-9.8). With the Lower Level Term “stuttering”, 584 cases were registered in the database of which 17 involved MPH. The ROR was 13.9 (95% CI: 8.6-22.5). This study found a signal for stuttering with MPH.