You don't have to accept our word for it, you simply have to google the side effects of this drug. This drug is an immuno-suppressant. Unless your immune system has gone into dangerous overdrive, which only happens in the late and deadly stage of the disease, taking the drug can harm you. If you have any sort of heart condition, it can kill you.
Because of the dangers and the side effects, this is not a drug you give for "preventative measures". All of this information is readily available if you google.
Google is now an accepted substitute for medical school and clinical experience. Good to know.
In discussions with internists and ID specialists, I'm told that the drug interferes with the virus penetrating a cell wall. In discussions with medical scientists, I'm told that the drug reduces viral load. No google needed, just comprehension and an open mind.
Any sort of heart condition? Not according to my cardiologist and five of his colleagues with whom I discussed the matter. The specific problem is interruption of a steady heartbeat with tachycardia or brachycardia, which is usually not a serious matter and is found only in <2% of patients taking the drug.
You're not quite right about the dangerous overdrive bit. There are many components to the immune system; two are a problem because one creates a cytokine storm, rapidly filling the lungs, and another creates serious inflammation in elastic lung walls, preventing their expansion and contraction (e.g., breathing). Once that has begun it's almost always too late.