The following categories are used to rank the undesirable effects by frequency of occurrence: very common (> 1/10); common (> 1/100 and < 1/10); uncommon (> 1/1000 and < 1/100); rare (> 1/10,000 and < 1/1000); and very rare (< 1/10,000), including isolated reports.
Kõrvaltoimete esinemissageduse kirjeldamiseks on kasutatud järgmisi kategooriaid: väga sage (> 1/ 10); sage (> 1/ 100, < 1/ 10); aeg- ajalt (> 1/ 1000, < 1/ 100); harv (> 1/ 10000, < 1/ 1000); väga harv (< 1/ 10000), sealhulgas üksikjuhud.