Here is the dosage. You have to figure that out depending on what type of medication you use. If it is in pills prescribed by your doctor it usually involves taking several pills at once based on your weight. Ivermectin is dosed by weight. If you use some other form it involves some math or looking long enough on line to find someone who has done the math and has divulged it. 

The basic dose is the same as a dose, pound for pound, of a horse (and some other animals including humans) for parasite control. The higher dosage rate for humans that is prescribed for some specific parasites is double that.

Last time I was at a farm store there was a sign put up that said officialdom was trying to get veterinary medicines to the point they could only be prescribed by a veterinarian and would no longer be sold over the counter without a prescription. So far that has not happened that I am aware of.

https://covid19criticalcare.com/protocol/i-care-early-covid-treatment/