Isotretinoin Treatment for Acne Vulgaris: A Five-Year Retrospective Analysis of Clinical and Biochemical Adverse Effects.

Objectives: Oral isotretinoin remains the most effective therapy for severe acne, but its exceptional efficacy is often accompanied by relatively frequent adverse effects. In this study, we quantified the frequency- and dose-related predictors of clinical and biochemical adverse effects during isotretinoin treatment in routine Polish practice. Methods: The records of 370 patients (mean age: 28 ± 12 years) who began isotretinoin treatment between June 2020 and June 2025 were reviewed. The mean daily isotretinoin and cumulative isotretinoin doses were 23.4 ± 9.1 mg and 88.3 ± 31.5 mg/kg, respectively. The adverse events documented at two-monthly visits were correlated with age and dosing. Lipid, hepatic, thyroid and prolactin panels were compared with age- and sex-matched controls using χ2 statistics and odds ratios (ORs). Results: Xerosis (70%), retinoid dermatitis (20%) and cheilitis (15.5%) predominated. Hand eczema rose with higher daily isotretinoin doses (ρ = 0.082; p = 0.037), whereas pruritus declined with greater cumulative isotretinoin exposure (ρ = -0.088; p = 0.037). Retinoid dermatitis was linked to a younger age (ρ = -0.080; p = 0.0286), whereas desquamation increased slightly with age (ρ = +0.083 p = 0.0228). Overall, dyslipidemia was twice as common as in the controls (OR: 2.06; 95% CI: 1.49-2.86; p-value: <0.0001), which was driven by an elevated total cholesterol (OR: 1.93; 95% CI: 1.34-2.77; p-value: 0.0004), LDL (OR: 3.40; 95% CI: 2.26-5.10; p-value: <0.0001) and triglycerides (OR: 1.95; 95% CI: 1.20-3.17; p-value: 0.0062) and decreased HDL (OR: 2.68; 95% CI: 1.75-4.10; p-value: <0.0001). Interestingly, hyperprolactinemia occurred eight-fold more often (OR: 8.42; 95%; 95% CI: 2.97-23.84; p-value: <0.00001). Aminotransferase and TSH elevations were infrequent and statistically non-significant. Conclusions: At moderate cumulative doses, isotretinoin was generally well tolerated; however, clinically relevant lipid and prolactin disturbances were frequent. Routine lipid and endocrine monitoring, early emollient prophylaxis and dose individualization are recommended to ensure safe isotretinoin usage in everyday practice.