| ATC Codes | Pharmacological Classification | Pharmacological Classification/DDD |
|---|---|---|
| N | NERVOUS SYSTEM | 神经系统 |
| N02 | ANALGESICS | 镇痛药 |
| N02A | OPIOIDS | 阿片碱类 |
| N02AA | Natural opium alkaloids | 天然阿片生物碱类 |
| N02AB | Phenylpiperidine derivatives | 苯哌啶衍生物 |
| N02AC | Diphenylpropylamine derivatives | 二苯丙胺衍生物 |
| N02AD | Benzomorphan derivatives | 苯并啡烷衍生物 |
| N02AE | Oripavine derivatives | 东罂粟碱衍生物 |
| N02AF | Morphinan derivatives | 吗啡烷衍生物 |
| N02AG | Opioids in combination with antispasmodics | 阿片生物碱类与解痉药的复方 |
| N02AJ | Opioids in combination with non-opioid analgesics | 阿片类药物联合非阿片类镇痛药 |
| N02AX | Other opioids | 其它生物碱类 |