Reporting Patterns of Sialorrhea Comparing Users of Clozapine to Users of Other Antipsychotics: A Disproportionality Analysis Using VigiBase

BACKGROUND: Sialorrhea is a non–life-threatening, but potentially invalidating adverse drug reaction (ADR) in patients using clozapine. In light of the very serious ADRs (agranulocytosis and myocarditis), sialorrhea is at risk to be overlooked by health care professionals. In this study, the sialorrhea reporting patterns of clozapine compared with other antipsychotics were assessed by evaluating differences in relative reporting frequency and reporter type. METHODS: A case/noncase disproportionality analysis using data from VigiBase (1968–2016) was performed. Reports of antipsychotics with “salivary hypersecretion” as ADR were considered as cases, and those with ADRs other than salivary hypersecretion were defined as noncases. Relative reporting frequencies were expressed as reporting odds ratios (RORs), and multivariate logistic regression was performed with the drug-ADR pair as unit of analysis to estimate RORs with 95% confidence intervals (CIs). RESULTS: A total of 1,169,254 drug-ADR pairs from 425,304 unique Individual Case Safety Reports were identified. Sialorrhea was relatively more frequently reported in clozapine (n = 2732 [1.1%]) compared with other antipsychotics (n = 2911 [0.31%]; ROR, 3.60; 95% CI, 3.41–3.79) and was reported relatively more often by consumers (ROR, 19.8; 95% CI, 15.1–25.9) compared with health care professionals (ROR, 2.44; 95% CI, 2.27–2.63). CONCLUSIONS: Sialorrhea was reported almost 4 times more often with clozapine use than with other antipsychotic use and was reported 8 times more often by patients than by health care professionals. This provides a signal of disproportion in sialorrhea occurrence among clozapine compared with other antipsychotics and in light of the disproportionality between reporter and an underreporting by health care professionals, underlining the importance to incorporate sialorrhea into the shared decision process when commencing clozapine therapy.