WHOCC
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Norwegian Institute of Public Health
WHO Collaborating Centre for Drug Statistics Methodology
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Norway

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N NERVOUS SYSTEM
N02 ANALGESICS

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.


N02A OPIOIDS

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.

The DDDs in this group are based on the treatment of pain.
The DDD for oral morphine is higher than the parenteral DDD because of lower bioavailability.

N02B OTHER ANALGESICS AND ANTIPYRETICS

See general considerations under N02.
Combinations with opioids should be classified in N02AJ - Opioids in combination with non-opioid analgesics. Combinations with codeine, non-opioid analgesics and psycholeptics are classified in N02AA79.
Combinations with opioids and antispasmodics are classified in
N02AG - Opioids in combination with antispasmodics.
Combinations with muscle relaxants are classified in M03B.
Combined preparations which contain more than one analgesic, should be classified by using the following ranking:
1. Phenacetin
2. Bucetin
3. Dipyrocetyl
4. Paracetamol
5. Acetylsalicylic acid
6. Phenazone
7. Salicylamide
8. Propyphenazone
This means that a product containing paracetamol and phenazone should be classified in N02BE51 - paracetamol, combinations excl. psycholeptics and not in N02BB51 - phenazone, combinations excl. psycholeptics.
Dextropropoxyphene plain, and in combination with other analgesics, is classified in N02AC.
Cold preparations with therapeutic levels of analgesics are classified in this group at separate 5th levels by using the 50-series.
Preparations are subdivided on 4th levels according to chemical structure.
Combinations with ascorbic acid (i.e. 50 mg or more per unit dose) are classified at separate 5th levels using the corresponding 50-series. Products containing less than 50 mg per unit dose are classified at the plain level of the analgesic component.

The DDDs are based on approved dose recommendations.
When establishing DDDs for combination products in the 50-series, all analgesic components are taken into consideration.
The DDD expressed in UD, should normally not exceed the approved dose recommendations for any of the components. See list of DDDs for combinations products, www.whocc.no.

N02C ANTIMIGRAINE PREPARATIONS

This group comprises preparations specifically used in the prophylaxis and treatment of migraine. Analgesics, see N02A and N02B.
Beta blocking agents, see C07.
Antivertigo preparations, see N07.
Cyproheptadine, see R06A - Antihistamines for systemic use.
Tolfenamic acid, see M01AG - Fenamates.
Indometacin in combination with prochlorperazine and caffeine is classified in M01AB51 - Indometacin, combinations.
Botulinum toxin used in the prophylactic treatment of migraine is classified in M03AX01.

Last updated: 2024-01-26