Oral Minoxidil for Alopecia Not Affected by Concurrent Antagonistic Medications

The efficacy of low-dose oral minoxidil for the treatment of alopecia may not be affected by the concomitant use of mechanistically antagonistic medications, according to a retrospective study.

Changes in median trichometric width and density were 5.5 μm and 18.5 hairs/cm² for those concurrently using antagonistic medications, such as non-steroidal anti-inflammatory drugs (NSAIDs) and stimulants, and 2.0 μm and 22.0 hairs/cm² for those not using antagonistic medications, reported Kristen Lo Sicco, MD, of the NYU Grossman School of Medicine in New York City, and colleagues.

There was no significant difference in the change of trichometric width (P=0.337) or density (P=0.229) between cohorts, they wrote in a research letter in JAAD International.

“Providers should encourage patients to adhere to their concurrent medications without fear of impeding progress in their hair growth journey,” the authors concluded.

At higher doses, oral minoxidil is approved by the FDA for hypertension. “When administered at low doses for alopecia, it is currently presumed to augment microcirculation surrounding the hair follicle, stimulating hair growth, with minimal blood pressure impacts,” Lo Sicco and team noted. Topical minoxidil (Rogaine) is approved by the FDA for androgenetic alopecia in men and women.

“Low-dose oral minoxidil has become a widely used therapy to promote hair growth and thickening in patients with alopecia,” Kathie Huang, MD, of Brigham and Women’s Hospital in Boston, told MedPage Today. “It acts on potassium channels in vascular smooth muscles, leading to vasodilation around hair follicles. This mechanism, among other potential effects, is thought to contribute to increased hair growth.”

Lo Sicco and colleagues noted that “alopecia patients frequently present with comorbid conditions, necessitating careful consideration when formulating treatment plans. This is particularly true when utilizing LDOM [low-dose oral minoxidil] for the treatment of androgenetic alopecia, as patients typically present in the third or fourth decade of life with a higher likelihood of concomitant medication use to manage comorbidities.”

“Our findings underscore that LDOM remains effective in treating alopecia, even in medically complex patients with multi-drug regimens involving antagonistic medications,” they added.

The antagonistic medications being used among this study population included formoterol (11%), NSAIDs (32%), stimulants (32%), tricyclic antidepressants (21%), triptans (16%), and oral steroids (5%).

The study was conducted from January 2009 through August 2023 and included 71 patients. Mean age was 37.3 years, and 60.6% were women. Most (91.5%) had been diagnosed with non-scarring alopecia.

Alopecia subtypes included androgenetic alopecia (71.8%), telogen effluvium and frontal fibrosing alopecia (2.8% each), androgenetic alopecia plus telogen effluvium (16.9%), and androgenetic alopecia plus lichen planopilaris (5.6%).

Side effects were reported by 23 patients, including hypertrichosis (22.5%), dizziness (4.2%), headache (4.2%), and fluid retention/edema (1.4%). There were no significant differences in incidence of side effects between the cohorts (P=0.27).

“Although low-dose oral minoxidil is often well-tolerated in patients with alopecia, potential side effects exist,” Huang cautioned. “Special consideration must be given when starting oral minoxidil in patients with cardiac medical diagnoses, edema, low blood pressure, or those on cardiac medications.”

“Patients may initially experience shedding and increased facial hair, so it is important to counsel them about these common potential side effects,” she added. “Patients should also avoid the medication during pregnancy.”

Limitations acknowledged by Lo Sicco and team included the study’s retrospective design, small sample size, use of patient-reported side effects, and lack of recorded changes in blood pressure, which they noted were nonsignificant in early research.

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