Table 2. Distribution of the main drug used and injecting drug use in medium-term residential centers in Tehran province .
| Drug type | No. (%) | IDU (%) | |
| Soft opioids n=551 (29.5%) |
Opium | 417 (75.7) | 17 (3.1) |
| Shireh-Opium | 50 (9.1) | ||
| Morphine | 46 (8.3) | ||
| Tramadol | 13 (2.4) | ||
| Methadone | 25 (4.5) | ||
| Hard opioids n=804 (43.0%) |
Heroin | 729 (90.7) | 24 (3.0) |
| Crack (of heroin) | 4 (0.5) | ||
| Hard + Soft opioids | 71(8.8) | ||
| Methamphetamine n=288 (15.4%) |
Methamphetamine | 257 (89.2) | 7 (1.7) |
| Soft opioids + Methamphetamine | 31 (10.8) | ||
| Methamphetamine + Hard opioids n= 225 (12.1%) |
255 (100) | 3 (1.3) | |
| Total | 1868 (100) | 51 (2.7) | |
Abbreviation: IDU, injecting drug use.
Sixty participants were using drugs other than the mentioned four categories, including one person who was using cocaine and 59 who were using cannabis. In these cases, 13 individuals used the main drug along with soft opioids, 20 with hard opioids, 5 with methamphetamine, and 21 with combination of methamphetamine and hard opioids.