I would say any human medicine is for exactly that... for humans only. Any usage of human medicine on any other species probably hasn't been widely tested. I doubt many humans would be willing to take medicine/drugs that were originally created for a dog/monkey/giraffe/fish without first consulting a doctor.
Any direction of use of human medicine should be given from someone with direct knowledge of the situation and has the training and/or background to make educated decisions (i.e. veterinarian)