An 80 kg person should receive a dose of 60 mg.
If the 0.75 mg/kg is the total daily dose, you will want to give 30 mg twice a day.
However, if the patient is to receive 0.75 mg/kg each time, then this will be 60 mg BID.
You will need to refer to your original question. The information is likely there, and you just omitted it for your posting. Refer to the 0.75 mg per kg if it is odered as total daily dose (divided) or is 0.75 mg/kg BID.
I hope this helps. If you have any questions, please let me know.