Dr. Robert Haber had a 67 y/o female patient for two years and she was taking 0.625mg minoxidil/day. She was in a minor fender bender accident with no evident physical damage or harm from the accident and no airbag deployment. She developed chest pain and in the Emergency Room after an extensive examination demonstrated that she has a pericardial effusion (‘water around the heart in the heart sac’). The doctors did not connect the accident and the cardiac problem identified, but knowing that oral minoxidil can produce this complication, her minoxidil was immediately stopped. Slowly the effusion subsided. This is a warning that a is known complication of minoxidil on higher doses. It was previously thought that doses 2.5 mg or less per day was safe from this complication. This may not be the case even at doses under 1mg/day. This is a risk everyone taking minoxidil should know about.
Now with that said, it is possible that this patient could have had Covid which is known to cause pericardial effusion. Even the vaccine has, in rare cases, caused pericardial effusion so maybe, just maybe the pericardial effusion was from another cause other than minoxidil. Here is an article that suggests a connection with Covid and pericardial effusion: https://www.statnews.com/2021/06/10/officials-higher-than-expected-heart-inflammation-cases-covid-19-vaccination/