Gender Differences in Adverse Effects and Dosing Practices of Low-Dose Oral Minoxidil for Androgenetic Alopecia: A Retrospective Analysis of 310 Patients.

Introduction: Off-label low-dose oral minoxidil (LDOM) is used for androgenetic alopecia (AGA) treatment, with limited safety data. We investigated LDOM adverse effects (AEs) in AGA patients. Methods: AGA patients taking LDOM were identified (January 1, 2010-December 3, 2022). AEs and management were recorded from follow-up and emergency room visits. Fisher's exact test, logistic regression, and Benjamini-Hochberg procedure assessed significance and adjusted for multiple comparisons. Results: Three hundred ten AGA patients were analyzed with mean age 47.5 years and 53.2% females. The average LDOM dose was lower for females vs. males. AEs were observed in 14.9% of patients, with dizziness/lightheadedness, hypertrichosis, and extremity edema being most common. Higher doses were associated with increased likelihood of dizziness/lightheadedness. Females had higher overall incidence of AEs; however, gender differences did not persist after subgroup analysis. Among patients experiencing AEs, 11.1% adjusted their dosage and 28.9% discontinued treatment. Conclusion: A higher LDOM dose increased risk of dizziness/lightheadedness in both genders, with females more likely to experience any AE. Patients are often started at inappropriately high doses, causing AE-induced regimen changes. Therefore, we recommend a cautious approach when prescribing LDOM, starting with lower doses and gradually increasing as tolerated, and counseling female patients regarding their higher risk of AEs.