Possible occurrence of paraesthesia in patients taking norethisterone: an analysis on the WHO Global Individual Case Reports database (VigiBase).

Abstract OBJECTIVE: Progestogens are widely used to treat a large number of common conditions. We aimed to investigate a potential signal concerning progestogens and paraesthesia. METHODS: Data were obtained from the VigiBase, the WHO Global Individual Case Safety Reports (ICSR) database, which is maintained by the Uppsala Monitoring Centre. We collected all suspected reports of paraesthesia associated with oral progestogens, reported between January 1972 and June 2012 and classified in VigiBase according to WHO-Adverse Reaction Terminology critical term 'paraesthesia'. A disproportionality analysis was conducted using the Information Component (IC) and the standard deviation (IC025) as a measure. RESULTS: Out of the total number of reports collected in the VigiBase (7,332,991), paraesthesia was associated with progestogen therapy in 920 reports, coming from 22 countries. Progestogens had the highest number of suspected reports (n = 864) than the other Anatomical Therapeutic Chemical (ATC) considered. Only norethisterone was associated with paraesthesia with positive IC (0.47) and IC025 (0.02). CONCLUSIONS: Norethisterone-associated paraesthesia appears to be a rare outcome. However, the widespread use of progestogens in medical practice suggests that it is a complaint that can affect a large number of women. Since paraesthesia can be caused by several drugs, clinicians should consider that it may be also caused by norethisterone.