Propyphenazone


Propyphenazone is a derivative of phenazone with similar analgesic and antipyretic effects. Originally patented in 1931, propyphenazone is marketed as a combination formulation with paracetamol and caffeine for treatment of primary headache disorder.

Serious adverse events

Case reports have described acute inferior-wall myocardial infarctions characterized by low atrial rhythms secondary to propyphenazone use.

Banned

Propyphenazone is banned in some countries including Sri Lanka, Malaysia, and Thailand.

Synthesis

Ethyl 2-isopropylacetoacetate and phenylhydrazine are combined to form the pyrazolone ring in the intermediate, which is alkylated with methyl iodide to yield propyphenazone.