Safety of low-dose oral minoxidil treatment for hair loss. A systematic review and pooled-analysis of individual patient data

Background: low dose oral minoxidil (OM) is an increasingly used treatment for androgenetic alopecia and other types of hair loss.

Objectives: to analyze available data of patients treated with OM, focusing on safety and adverse effects.

Methods: a search in PubMed and EMBASE was performed for studies reporting the treatment of alopecia with OM. Individual patient data available for pooled-analysis were sex, dose of OM, presence of hypertrichosis and lower limb edema.

Results: 14 studies including 442 patients were analyzed. OM was used at doses between 0.25 and 5 mg, for 8 different types of alopecia. Hypertrichosis was observed in 24% of patients. All doses had an increased odds ratio of hypertrichosis, compared to 0.25-0.5mg (p<0.001). Pedal edema was observed in 2% and was also associated with higher doses of OM (p=0.009). Postural hypotension and heart rate alterations occurred only in 1.1% and 1.3% of the patients, respectively. Efficacy of OM could not be analyzed due to heterogeneous studies. However, 4 studies using OM for androgenetic alopecia reported a clinical response in 70 - 100% of the patients.

Conclusions: low dose OM is a safe and well-tolerated treatment for hair loss, presenting a lower adverse effect rate than standard doses. This article is protected by copyright. All rights reserved.