Oral minoxidil, 5 mg once a day, “did not demonstrate superiority” over topical minoxidil, 5%, applied twice a day, after 24 weeks, reported Mariana Alvares Penha, MD, of the department of dermatology at São Paulo State University, in Botucatu, Brazil, and coauthors. Their randomized, controlled, double-blind study was published online in JAMA Dermatology.
Topical minoxidil is approved by the US Food and Drug Administration (FDA) for androgenetic alopecia (AGA), but there has been increasing interest worldwide in the use of low-dose oral minoxidil, a vasodilator approved as an antihypertensive, as an alternative treatment.
The trial “is important information that’s never been elucidated before,” Adam Friedman, MD, professor and chair of dermatology at George Washington University, Washington, said in an interview. The data, he added, can be used to reassure patients who do not want to take the oral form of the drug that a topical is just as effective.
“This study does let us counsel patients better and really give them the evidence,” said Shari Lipner, MD, PhD, associate professor of clinical dermatology at Weill Cornell Medicine, New York, who was also asked to comment on the results.
Both Dr. Lipner and Dr. Friedman said the study was well-designed.
The investigators enrolled 90 men aged 18-55; 68 completed the trial. Most had mild to moderate AGA. Men were excluded if they had received treatment for alopecia in the previous 6 months, a history of hair transplant, cardiopathy, nephropathy, dermatoses involving the scalp, any clinical conditions causing hair loss, or hypersensitivity to minoxidil.
They were randomized to receive either 5 mg of oral minoxidil a day, plus a placebo solution to apply to the scalp, or topical minoxidil solution (5%) applied twice a day plus placebo capsules. They were told to take a capsule at bedtime and to apply 1 mL of the solution to dry hair in the morning and at night.
The final analysis included 35 men in the topical group and 33 in the oral group (mean age, 36.6 years). Seven people in the topical group and 11 in the oral group were not able to attend the final appointment at 24 weeks. Three additional patients in the topical group dropped out for insomnia, hair shedding, and scalp eczema, while one dropped out of the oral group because of headache.
At 24 weeks, the percentage increase in terminal hair density in the oral minoxidil group was 27% higher (P = .005) in the vertex and 13% higher (P = .15) in the frontal scalp, compared with the topical-treated group.
Total hair density increased by 2% in the oral group compared with topical treatment in the vertex and decreased by 0.2% in the frontal area compared with topical treatment. None of these differences were statistically significant.
Three dermatologists blinded to the treatments, who analyzed photographs, determined that 60% of the men in the oral group and 48% in the topical group had clinical improvement in the frontal area, which was not statistically significant. More orally-treated patients had improvement in the vertex area: 70% compared with 46% of those on topical treatment (P = .04).