A pharmaceutical composition containing isomyosmine or a pharmaceutically acceptable salt thereof is administered to an individual in need thereof for treating a substance addiction, inclusive of addiction to heroin (diacetylmorphine), cocaine, opioids, methadone, d-methamphetamine, barbiturates, alcohol, benzodiazepines, amphetamines, or buprenorphine. The isomyosmine, along with optional additional therapeutic agent(s), may be administered in a capsule, tablet, or lozenge.
