u003cstrongu003eA:u003c/strongu003e When doctors prescribe medication during the treatment process, the medications are intended to offer relief to the client. There are also times when clients enter rehab with a doctor's prescription in place for a drug to treat a mental or psychological disorder. To determine the total rehab costs related to prescription medication, one would also have to factor in the length of the client's detox and therapy treatments. As a general rule of thumb, prescription drug costs can run from $1,500 up to as much as $3,000 over the entire treatment process.