Los of well known unpleasant side effects? The known unpleasant side-effects is a stomach ache and feeling bad if you take a horse sized dose (assuming you aren't allergic to it of course).
On normal doses, fever, itching, and skin rash when taken by mouth; and red eyes, dry skin, and burning skin when used topically for head lice.
On large overdoses — which I don't normally count but which would be necessary for actually inhibiting the covid virus because even in vitro that only happened at 35x the maximum FDA-approved dosage — central nervous system depression, ataxia, nausea, vomiting, diarrhea, hypotension, decreased level of consciousness, confusion, blurred vision, visual hallucinations, loss of coordination and balance, seizures, coma, and death.
(But apart from that, Mrs. Lincoln, how was the play?)
Safe dose: mildly unpleasant, and also ineffective.
Effective dose (in a petri dish): very unpleasant and possibly lethal.
