Compliance with the European Pregnancy Prevention Programme in Isotretinoin Treatment: Safety Outcomes and Dose-Related Correlations.

Isotretinoin is a highly effective treatment for moderate-to-severe acne, but strict contraceptive measures are required because of its teratogenicity. The European Pregnancy Prevention Programme (PPP) aims to minimise foetal exposure through structured protocols. However, real-world data on patient compliance and treatment outcomes are limited. This retrospective study included 569 female patients aged 14-25 years treated with isotretinoin in Poland (2021-2022). Patients were assigned to three groups based on PPP compliance: full (Group I), partial (Group IIA), and minimal (Group IIB). Data on contraception, cumulative dose, treatment duration, adverse events, laboratory monitoring, and therapy discontinuation were analysed using non-parametric statistical tests ( < 0.05). No pregnancies occurred during treatment. Overall compliance with PPP requirements was high: 100% of the patients used contraception or declared abstinence. The majority (92.79%) used condoms, 1.93% used oral contraceptives, and 7.21% reported abstinence. Significant differences in cumulative isotretinoin dose were observed between the groups (Kruskal-Wallis H = 19.89, < 0.001), with Group I receiving a lower mean dose than those in Groups IIA ( < 0.001) and IIB ( < 0.01). Notably, all therapy discontinuations (4.75%) occurred in Group I (full compliance), which may reflect stricter monitoring and an earlier identification of adverse effects or patient concerns. These discontinuations were associated with lower cumulative dosing (Mann-Whitney Z = 7.81, < 0.001) than that seen in the other groups. An inverse correlation between age and cumulative dose was also found (H = 13.09, = 0.0004), with younger patients (≤17 years) more likely to reach therapeutic targets. Isotretinoin therapy under structured PPP protocols is safe and effective, with no pregnancies reported and excellent contraceptive compliance. Significant differences in dosing and adherence patterns highlight the need for flexible patient-centred approaches to optimise safety and outcomes.