Low-dose oral minoxidil (LDOM; 0.25- 5 mg/d) is not only increasingly popular but it’s effective too. Males with androgenetic alopecia area often treated with 2.5 to 5 mg. Although LDOM is much safer than the doses used for blood pressure control in the 1970s and 1980s (10-50 mg), low dose oral minoxidil can sometimes still affect blood pressure and heart rate. Moreover some patients are very sensitive to the drug and find cardiovascular side effects challenging. Fortunately, that’s fairly rare. Authors of a new study set out to determine how labs blood pressure and heart range change with oral minoxidil use over 24 weeks.
Sanabria et al, 2022
Sanabria and colleagues from Brazil set out to assess the clinical, laboratorial, and cardiovascular effects in male adults taking 5-mg oral minoxidil at bedtime for androgenetic alopecia. The authors assessed the biochemical profile, 24-hour Holter monitoring, and 24-hour ambulatory blood pressure monitoring before starting treatment (T0) and then at 24 weeks (T24).
34 men health males aged 21 to 58 years without cardiovascular disease were included in the study. Four participants left the study 2 because of headache, 1 because of facial and leg edema, and 1 because of reasons unrelated to the treatment.
At the 24 week follow-up time point , 7 (20.6%) participants reported headache, whereas 1 (2.9%) participant reported vertigo and another participant (2.9%) reported edema. Shortness of breath and heart palpitations were not reported, and no symptomatic cardiovascular outcomes were observed.
Nineteen (55.9%) participants reported increased hair on the body (hypertrichosis).
Lab Changes with Oral Minoxidil
There were no changes in laboratory variables such as cholesterol, AST, ALT, sodium, potassium, creatinine or glucose.
Blood Pressure Changes with 5 mg ORAL MINOXIDIL
One participant presented with hypertension (blood pressure of [140/90 mm Hg) before treatment was started and another had high blood pressure at T24. None of the patients had hypotension (blood pressure of \90/60 mm Hg) during the 24-hour monitoring period. The mean awake arterial pressure was slightly reduced at T24 from 92.6 mm Hg to 89.8 mm Hg (p=0.015) .
The mean systolic awake blood pressure drop from 125 to 122 mm Hg (p=0.031) and the mean diastolic awake blood pressure dropped from 76 to 74 mm Hg (p=0.024).
Older patients were slightly more likely to have a reduction in mean arterial pressure.
Heart Rate Changes with 5 mg ORAL MINOXIDIL
1 patients developed tachycardia at T24. This equates to 3.3 %. Overall, there was no change in mean heart rate. There was no statistically significant increase in ventricular or supraventricular extrasystoles.
Older patients were slightly more likely to have extrasystoles.
This is such a wonderful study. It’s really much needed study in our field. Oral minoxidil in males is quite well tolerated and has a good safety profile. Systolic pressure and diastolic pressure change so very little and moreso in older males. An occasional patient can be expected to have tachycardia – and that was around 3 % in this study
The authors point out that this was a study of healthy males. It wasn’t a study of women. It wasn’t a study of males with cardiovascular disease. It wasn’t a study of males over 60.
There’s still a bit of work to do in other subgroups to get a sense of its overall safety.
It appears that low dose oral minoxidil is quite safe. I’d like to see some long term studies of left ventricular mass and left vetricular hypertrophy in long term users. I’d be pretty reassured with that kind of data.
But overall, this is a wonderful study and really helps clarify so many things about the cardiovascular safety of oral minoxidil.
Sanabria et al. Prospective cardiovascular evaluation with 24-h Holter and 24-h ambulatory blood pressure monitoring in men using 5 mg oral minoxidil for androgenetic alopecia. J Am Acad Dermatol . 2022 May 18;S0190-9622(22)00821-0.