This group comprises general analgesics and antipyretics.
All salicylic acid derivatives except combinations with corticosteroids (M01B) or opioids (N02AJ) are classified in N02BA - Salicylic acid and derivatives, as it is difficult to differentiate between the use of salicylates in rheumatic conditions and other therapeutic uses of salicylates.
All plain ibuprofen preparations are classified in M01A, even if they are only intended for use as pain relief.
There are a number of combined preparations, which contain analgesics and psycholeptics. These are classified in N02, as pain relief must be regarded as the main indication. Analgesics used for specific indications are classified in the respective ATC groups. E.g.:
A03D/
A03EA- Antispasmodic/psycholeptics/analgesic combinations
M01 - Antiinflammatory and antirheumatic products
M02A - Topical products for joint and muscular pain
M03 - Muscle relaxants
See comments to these groups.
Lidocaine indicated for postherpetic pain is classified in N01BB.

This group comprises strong analgesics of the opiate type and analgesics with similar structure or action.
Sufentanil, which is also used as an epidural analgesic or in postoperative pain, is classified in N01AH.
Fentanyl in combination with bupivacaine used in e.g. postoperative pain is classified in N01AH51 - fentanyl, combinations.
Combinations with antispasmodics are classified in N02AG.

This group includes natural and semi-synthetic opiates.
All plain morphine preparations are classified in this group.
Opium, see also A07DA - Antipropulsives.
Plain codeine preparations are classified in R05D - Cough suppressants, excl. combinations with expectorants, while dihydrocodeine is classified in N02AA. Codeine or dihydrocodeine in combination with other analgesics or NSAIDs are classified in N02AJ - Opioids in combination with non-opioid analgesics.
Other combinations with e.g. caffeine, antihistamines and anticholinergic agents are classified in N02AA. Combinations of codeine with psycholeptics are classified in N02AA79.