Safety of low-dose oral minoxidil for hair loss: a multicenter study of 1404 patients

BACKGROUND: The major concern regarding the use of low-dose oral minoxidil (LDOM) in the treatment of hair loss is the potential risk of systemic adverse effects.OBJECTIVE: To describe the safety of LDOM for the treatment of hair loss in a large cohort of patients.METHODS: Retrospective multicenter study of patients treated with LDOM for at least 3 months as a treatment for any type of alopecia.RESULTS: A total of 1404 patients [943 women (67.2%) and 461 men (32.8%)] with a mean age of 43 years (range 8-86) were included. From them, the dose of LDOM was titrated in 1065 patients, allowing the analysis of 2469 different cases. The most frequent adverse effect was hypertrichosis (15.1%) which led to treatment withdrawal in 14 patients (0.5%). Systemic adverse effects included lightheadedness (1.7%), fluid retention (1.3%), tachycardia (0.9%), headache (0.4%), periorbital edema (0.3%) and insomnia (0.2%), leading to drug discontinuation in 29 patients (1.2%). No life-threatening adverse effects were observed.LIMITATIONS: Retrospective design, lack of a control group.CONCLUSION: LDOM has a good safety profile as a treatment for hair loss. Systemic adverse effects were infrequent and only 1.7% of patients stopped the treatment due to adverse effects