Phenacetin (Molecule of the Month for December 2006)
Phenacetin, introduced in 1887, is used principally as an analgesic painkiller. Its analgesic effects are due to its actions on the sensory tracts of the spinal cord. In addition, phenacetin has a depressant action of the heart, where it acts as a negative inotrope (weaken the force of muscular contractions). It also is an antipyretic, used to reduce fever by lowering the body temperature.
Phenacetin, and products containing phenacetin have been shown in an animal model to be carcinogenic. In humans, many case reports have implicated products containing phenacetin in urothelial neoplasms, especially transitional cell carcinoma of the renal pelvis. In one prospective series, phenacetin was associated with an increased risk of death due to urologic or renal diseases, death due to cancers, and death due to cardiovascular diseases. The painkiller was initially banned from general use in 1968 after it was linked to bladder and kidney cancer. The ban was later revoked - but its legal use is highly restricted because of the dangers it poses.
Phenacetin is now being widely used as a cutting agent to adulterate illegally supplied cocaine due to the similar physical features of the two drugs. The average purity of manufactured cocaine is 70%. But investigators believe dealers in Britain are now selling the drug with purity as low as 30%. So if Phenacetin is used to provide this extra bulk, then on top of the risks of taking cocaine, there is an increased cancer risk.
Update by Karl Harrison
(Molecule of the Month for December 2006 )