| T400X6S | Underdosing of opium, sequela |
| T401 | Poisoning by and adverse effect of heroin |
| T401X | Poisoning by and adverse effect of heroin |
| T401X1 | Poisoning by heroin, accidental (unintentional) |
| T401X1A | Poisoning by heroin, accidental (unintentional), init encntr Poisoning by heroin, accidental (unintentional), initial encounter |
| T401X1D | Poisoning by heroin, accidental (unintentional), subs encntr Poisoning by heroin, accidental (unintentional), subsequent encounter |
| T401X1S | Poisoning by heroin, accidental (unintentional), sequela |
| T401X2 | Poisoning by heroin, intentional self-harm |
| T401X2A | Poisoning by heroin, intentional self-harm, initial encounter |
| T401X2D | Poisoning by heroin, intentional self-harm, subsequent encounter |
| T401X2S | Poisoning by heroin, intentional self-harm, sequela |
| T401X3 | Poisoning by heroin, assault |
| T401X3A | Poisoning by heroin, assault, initial encounter |
| T401X3D | Poisoning by heroin, assault, subsequent encounter |
| T401X3S | Poisoning by heroin, assault, sequela |
| T401X4 | Poisoning by heroin, undetermined |
| T401X4A | Poisoning by heroin, undetermined, initial encounter |
| T401X4D | Poisoning by heroin, undetermined, subsequent encounter |
| T401X4S | Poisoning by heroin, undetermined, sequela |
| T402 | Poisoning by, adverse effect of and underdosing of other opioids |
| T402X | Poisoning by, adverse effect of and underdosing of other opioids |
| T402X1 | Poisoning by other opioids, accidental (unintentional) |
| T402X1A | Poisoning by other opioids, accidental (unintentional), initial encounter |
| T402X1D | Poisoning by other opioids, accidental (unintentional), subsequent encounter |
| T402X1S | Poisoning by other opioids, accidental (unintentional), sequela |
| T402X2 | Poisoning by other opioids, intentional self-harm |
| T402X2A | Poisoning by oth opioids, intentional self-harm, init encntr Poisoning by other opioids, intentional self-harm, initial encounter |
| T402X2D | Poisoning by oth opioids, intentional self-harm, subs encntr Poisoning by other opioids, intentional self-harm, subsequent encounter |
| T402X2S | Poisoning by other opioids, intentional self-harm, sequela |
| T402X3 | Poisoning by other opioids, assault |
| T402X3A | Poisoning by other opioids, assault, initial encounter |
| T402X3D | Poisoning by other opioids, assault, subsequent encounter |
| T402X3S | Poisoning by other opioids, assault, sequela |
| T402X4 | Poisoning by other opioids, undetermined |
| T402X4A | Poisoning by other opioids, undetermined, initial encounter |
| T402X4D | Poisoning by other opioids, undetermined, subsequent encounter |
| T402X4S | Poisoning by other opioids, undetermined, sequela |
| T402X5 | Adverse effect of other opioids |
| T402X5A | Adverse effect of other opioids, initial encounter |
| T402X5D | Adverse effect of other opioids, subsequent encounter |
| T402X5S | Adverse effect of other opioids, sequela |
| T402X6 | Underdosing of other opioids |
| T402X6A | Underdosing of other opioids, initial encounter |
| T402X6D | Underdosing of other opioids, subsequent encounter |
| T402X6S | Underdosing of other opioids, sequela |
| T403 | Poisoning by, adverse effect of and underdosing of methadone Poisoning by, adverse effect of and underdosing of methadone |
| T403X | Poisoning by, adverse effect of and underdosing of methadone Poisoning by, adverse effect of and underdosing of methadone |
| T403X1 | Poisoning by methadone, accidental (unintentional) |
| T403X1A | Poisoning by methadone, accidental (unintentional), initial encounter |
| T403X1D | Poisoning by methadone, accidental (unintentional), subsequent encounter |