Safety classification of drugs
In this database, drugs are classified into five categories reflecting the risk of provoking an acute attack. The categories range from Non-porphyrinogenic containing drugs that can be used safely, to the high-risk Porphyrinogenic class, containing drugs which should be prescribed only on urgent indications. Read more about the criteria used for this classification of drugs.

Key to drug porphyrinogenicity classifications with colour codes and abbreviations used in the database, and advice for prescription:

Drug classifications
Advice for prescription
Not porphyrinogenic (NP)
Used as a first hand choice
No precautions needed
Probably not porphyrinogenic (PNP)
Used as a first hand choice
No precautions needed
Possibly porphyrinogenic (PSP)
Only used when no safer alternative is available.
Precautions motivated in vulnerable patients.
Probably porphyrinogenic (PRP)
Prescribed only on strong or urgent indications.
Precautions motivated in all patients.
Porphyrinogenic (P)
Prescribed only on urgent indications.
Precautions taken in all patients.
Not yet classified (NC)
Not yet safety classified and should therefore not be used. Prescribed only on strong indication when no safer alternative is available. Seek advice from a porphyria specialist .

Choice of drug for a porphyric
  • When a prescription is necessary, select drugs in the order NP, PNP, PSP, PRP, P.
  • First hand choice: Try to find a drug classified as NP or PNP.
  • Before prescribing any drug labeled PSP, PRP or P, doctors must justify that a very real need for the drug exists and that no safer alternative is available.
  • The benefit from using the drug of choice should always be assessed against the risk of provoking an acute attack and the likely consequences of not using it.
  • A drug should never be withheld if it is judged to be essential for optimum treatment.
  • For potentially unsafe drugs (PSP, PRP, P), monitoring urinary PBG excretion should be carried out in collaboration with a specialist porphyria center to detect any drug-provoked increase. It is also recommended to seek advice from a porphyria expert.

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