Ivermectin is pretty safe, prescription or animal: Exactly the same stuff, as long as the animal drug has no other active ingredients. I read one article today that accurately stated the problem, and that is figuring out the dosage. If you take enough horse dewormer to treat a horse, you will wind up in the hospital. If you take dog heartworm meds that contain other drugs, you might wind up dead. If you take prescription ivermectin and have a leaky blood/brain barrier (like me?) you could have permanent brain damage. There are several diseases and conditions that cause that, none of them fun.
There is a new drug in trials called Molnupiravir, that makes RNA replication fail by substituting junk base pairs. The new RNA does not work, so the virus can't reproduce. The reason it works is that animals don't do RNA replication, just RNA viruses. Assuming the trials pan out, this could make early treatment flawless. And it's pretty unlikely they would get to Phase III trials if it wasn't pretty safe and effective. The Biden administration has agreed to buy 1.2 billion dollars worth of it from Merck, upon EUA. The bonus is it also works against SARS-COV1 and MERS. In fact, it will probably work against any positive sense single strand RNA virus! Such as Poliovirus, Rhinovirus (a common cold virus), Hepatitis A virus, Hepatitis C virus, Norwalk virus, Yellow Fever virus, West Nile virus, Dengue fever virus, Zika virus, Rubella virus, Chikungunya virus, and many more rare viruses. Less likely but still possible are the positive sense RNA viruses like Ebola virus, Marburg virus, Lhasa virus, Measles virus, Mumps virus, Nipah virus, Hendra virus, Rabies, and Influenza.