Experiments indicate that currently available methadone disks can, with a little ingenuity, be converted into the injectable form. This is of potential concern since methadone, when injected intravenously, is similar to other opiates in its psychopharmacological effects. The possible misuse of these disks can be avoided by dispensing the medicine in natural or certain artificial juices.
Jaffe JH, Fritz K, Kaistha KK. Methadone DisksInjectable-Noninjectable Tablets. Arch Gen Psychiatry. 1971;25(6):525-526. doi:10.1001/archpsyc.1971.01750180045008