The researchers found that the highest dose of buprenorphine (16 mg daily) was the most effective at stopping both heroin and cocaine use, as well as decreasing use in those who continued to test positive. In the group receiving 16 mg a day, the percentage of all urine samples testing positive for heroin fell by 43 percent, and the number testing positive for cocaine fell by nearly 53 percent. Urine concentrations in those samples continuing to test positive for heroin use fell by 92 percent, and in those continuing to test positive for cocaine use, by 95 percent. The group taking 8 mg a day of buprenorphine also had statistically significant reductions in both the number of sample continuing to test positive for heroin and cocaine and the amount of drug used. However, the effect was much smaller.