Pericardial effusions not prevalent among patients with alopecia treated with minoxidil

Key takeaways:

• Three patients in both the treatment and nontreatment groups developed small, asymptomatic pericardial effusions.
• Duration of minoxidil treatment was not associated with the development.

Low-dose oral minoxidil was not significantly associated with pericardial effusion among patients with alopecia, according to a study.

“Low-dose oral minoxidil (LDOM) is being increasingly prescribed off-label as an adjunct treatment for alopecia,” Colin M. Kincaid, MD, a research fellow in the department of dermatology at the University of California, Irvine, at the time of the study and a current resident physician at Scripps Health, and colleagues wrote. “However, a recent report of anasarca and pericardial effusion developing shortly after initiating LDOM therapy in a healthy woman with frontal fibrosing alopecia has prompted concern within the dermatology community for potentially serious complications.”

In this cross-sectional study, the authors used ultrasounds to evaluate the association between LDOM treatment for alopecia and the development of pericardial effusion in 100 patients with alopecia, 51 of which received LDOM (mean age, 53.7 years; 86% female) and 49 that did not (mean age, 54.1 years; 73% female).

Of the patients receiving LDOM, 70% were on a 2.5 mg daily dose and 21% were on a 1.25 mg daily dose. The average length of time receiving treatment was 11.8 months.

Results showed that three LDOM patients (5.8%) and three control patients (6%) developed small, asymptomatic pericardial effusions less than 1 cm in size. The treatment duration of the patients in the LDOM group that developed pericardial effusions was approximately 11.4 months vs. 11.8 months in the LDOM-treated patients that did not have pericardial effusions, suggesting that treatment duration was not associated with the adverse event.

According to the authors, the mechanism by which minoxidil may cause pericardial effusions is unknown. Theories such as minoxidil’s propensity to cause fluid retention, vasodilation and dilation of epicardial capillaries have been discussed, but none reliably proven.

While the authors agreed that their study ultimately showed a lack of difference in effusion rates between LDOM-treated patients and controls, the almost 6% rate of small effusions in the LDOM group was notable.

“This was surprising as the original FDA warning (1980) suggests that pericardial effusions were present in 3% of hypertensive patients on minoxidil,” the authors wrote. “However, more recent studies of the general population have estimated the prevalence of pericardial effusions to be 6.5% to 9%, many of which were found in individuals who had no cardiovascular disease.”

Although the authors state that these discrepancies could be explained by study methods, larger, prospective studies are needed to elucidate these findings.