I am going to share Bill's experience with taking antihistamines for his long covid episodes of fatigue. I am not suggesting this is a cure for long covid or that it will work for every one. Just sharing what is working for him. Three weeks ago while searching for long covid help I ran across a small study from the UK about people who took two different types of antihistamines and discovered their extreme fatigue episodes went away. So we tried it. Bill was already taking Famotidine two a day for his stomach. Famotidine is also an antihistomine. So we added one Zyrtec a day. He takes it at night. Since then he has not had one episode of fatigue, not one! Also no brain fog. I can see the difference in his walk, back to his old strut and the difference in his voice. Today I went on line and searched for "long covid and antihistomines" and discovered several articles. Some people recovered their sense of taste and smell, no more brain fog, no more extreme fatigue, etc.
Like I said, I am just sharing Bill's experience. I am not recommending any thing. But check out the articles. Our doctor hadn't heard of this but agreed he could try it. Maybe you know someone who could also benefit from reading the articles and checking with their doctors.