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. 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.

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. It is also used in measuring the total body water in the human body system.