From Wikipedia, the free encyclopedia
INN: aminophenazone
Clinical data
AHFS/Drugs.comInternational Drug Names
ATC code
Pharmacokinetic data
  • 4-Dimethylamino-1,5-dimethyl-2-phenylpyrazol-3-one
CAS Number
PubChem CID
CompTox Dashboard (EPA)
ECHA InfoCard100.000.332 Edit this at Wikidata
Chemical and physical data
Molar mass231.29358 g·mol−1
3D model (JSmol)
  • O=C2\C(=C(/N(N2c1ccccc1)C)C)N(C)C
  • InChI=1S/C13H17N3O/c1-10-12(14(2)3)13(17)16(15(10)4)11-8-6-5-7-9-11/h5-9H,1-4H3 checkY

Aminophenazone (or aminopyrine, amidopyrine, Pyramidon) is a non-narcotic analgesic substance. It is a pyrazolone and a derivative of phenazone, which also has anti-inflammatory and antipyretic properties. While inexpensive and effective, especially in the treatment of rheumatism, the drug carries a serious risk of severe and sometimes fatal side-effects, including agranulocytosis.[2] While its production and use have been banned in many countries, including France, Thailand, India and Japan, it is still sometimes used in the developing world.[2]

A breath test with 13C-labeled aminopyrine has been used as a non-invasive measure of cytochrome P-450 metabolic activity in liver-function tests.[1] It is also used in measuring the total body water in the human body system.[3]


Aminophenazone was first synthesized by Friedrich Stolz and Ludwig Knorr in the late nineteenth century, and sold as an anti-fever medicine known as Pyramidon by Hoechst AG from 1897 until its eventual replacement[when?] by the safer propyphenazone molecule.


Symptoms of exposure to this compound include:[4]

  • allergic reactions
  • strong spasmolytic effect on smooth muscle of peripheral blood vessels
  • irritability
  • palsy
  • copious sweating
  • dilated pupils
  • sharp drop then rise in body temperature
  • dysuria
  • dyspnea
  • anxiety
  • rectal tenesmus
  • urinary frequency
  • intermittent fever
  • fatty infiltration of the liver
  • heart muscle degeneration
  • death due to circulatory failure following cardiovascular collapse

Agranulocytosis often occurs. Ingestion may cause central nervous system stimulation, vomiting, convulsions, cyanosis, tinnitus, leukopenia, kidney damage and coma. Ingestion may also lead to nausea, mental disturbances, methemoglobinemia, chocolate-colored blood, dizziness, epigastric pain, difficulty in hearing, thready pulse and liver damage.

Other symptoms reported via ingestion include hemolytic anemia, porphyria and severe gastrointestinal bleeding. Bone marrow depression also occurs. Rare eye effects include acute transient myopia.

Chronic symptoms include:

When heated to decomposition this compound emits toxic fumes of nitrogen oxides.


Amidopyrine is metabolized by demethylation and acetylation. Amidopirina metabolites are 4-aminoantipyrine, metilaminoantipirin, rubazonovaya and metilrubazonovaya acid. These acids have a reddish color. At high amidopirine doses, urine can have a reddish brown coloration, due to the presence in the urine of these acid markers.[5]


  1. ^ a b Caubet MS, Laplante A, Caillé J, Brazier JL (June 2002). "[13C]aminopyrine and [13C]caffeine breath test: influence of gender, cigarette smoking and oral contraceptives intake". Isotopes in Environmental and Health Studies. 38 (2): 71–7. doi:10.1080/10256010208033314. PMID 12219983. S2CID 22002940.
  2. ^ a b Panchal, J (29 January 2021). "A Review: Why Aminopyrine Banned?" (PDF). Scholars Academic Journal of Pharmacy.
  3. ^ "Aminophenazone — Compound Summary". PubChem. The National Library of Medicine. 2005-03-26. Retrieved June 12, 2008.
  4. ^ Pubchem. "aminophenazone". Retrieved 2017-11-09.
  5. ^ Vyzanie. "Amidopirina". Retrieved 2017-11-09.