If Ivermectin is made available on prescription or over the counter why would people use incorrect veterinary formulations? Ivermectin together with Hydroxychl

If Ivermectin is made available on prescription or over the counter why would people use incorrect veterinary formulations? Ivermectin together with Hydroxychloroquine are safe drugs OTC which have been around longer than the Covid vaccines, yet for some reason they are now considered more dangerous then Covid vaccines which have killed and injured more people in the short time they have been available. Hydroxychloroquine is an over the counter drug in the US in the form of plaquenil, and Ivermectin is in other countries. Why has Covid suddenly made them so dangerous?