Propyphenazone, a pyrazolone derivative with anti-inflammatory, analgesic and antipyretic activity, was introduced in 1951 for the treatment of rheumatic disorders. As it is structurally related to aminophenazone it has been associated with severe blood dyscrasias. However, it cannot be transformed into potentially carcinogenic nitrosamines and has therefore been widely used as a replacement drug for aminophenazone. In certain countries, products containing propyphenazone have now been restricted in their indications, whereas in others they are still available, sometimes as over-the-counter preparations.[6]
↑Akyel A, Alsancak Y, Yayla Ç, Sahinarslan A, Özdemir M (May 2011). "Acute inferior myocardial infarction with low atrial rhythm due to propyphenazone: Kounis syndrome". International Journal of Cardiology. 148 (3): 352–3. doi:10.1016/j.ijcard.2010.05.038. PMID20541820.
