Variations between package inserts regarding gingival overgrowth causing drugs

Drug-induced gingival overgrowth (DIGO) is an increasingly relevant topic among dentists, physicians and patients as well. Due to high prescription rates of calcium channel blockers, anticonvulsants and immunosuppressants, the prevalence of this adverse effect should not be underestimated. In this paper, we compare the three groups of active substances mentioned and work out the drugs with the highest risk of triggering DIGO. Additionally, we compared package inserts (PIs) of the drugs in question to identify differences and missing references to this adverse drug reaction (ADR). It is a well-known problem that package inserts sometimes contain different information about adverse drug reactions and their frequencies. To find out what prevalence can actually be expected, we analysed various package inserts for different drugs that are known to cause DIGO. Moreover, we compared package inserts with summary of product characteristics (SmPCs) as an example. It turned out that both pieces of information shed light on the circumstances and problems of DIGO with roughly the same degree of imprecision and incompleteness. Furthermore, the given information in SmPCs are sometimes even worse than in the PIs. To find out the prevalence with which the various drugs potentially trigger DIGO, recent prescription figures must be taken into account. Using current data from the Arzneiverordnungsreport (drug prescription report, AVR) 2023 and the prevalences stated in PIs, we performed a model calculation of the expected number of patients in Germany developing DIGO per year. It turned out that substantial differences in the frequencies and the reported adverse drug reactions in the different package inserts can be found. Apart from this, the compared SmPC do not contain any further information on DIGO and its frequency. Surprisingly, long-term therapy with valproic acid is associated with the highest rate of DIGO compared to the other drugs. Despite the lower number of prescriptions, significantly more cases of DIGO must be expected with valproic acid therapy than with amlodipine or phenytoin, for example. To summarise, there are significant differences in the content of package inserts from different manufacturers. As a source of information for healthcare professionals, the SmPC unfortunately does not provide any detailed information on DIGO. In patients receiving long-term therapy with valproic acid, particular attention must be paid to the development of DIGO to initiate therapy at an early stage.