Cocaine is often cut with adulterants in order to increase profits for dealers. Usually the substances that are added are chosen because they match the appearance and have a similar numbing effect like cocaine does.
* Link here for more information on these adulterants
In Australia cocaine’s purity levels are pretty low. As can be seen in the chart purity ranges from an average of 30% to as little as 10% across the nation, compared to the average purity in North America at 56%. Levamisole, diltiazem and hydroxyzine have been found in Australia’s cocaine supply.