8. What was the reason that the first discovered “statin” (HMG CoA reductase inhibitor) was never used in humans?

The first statin discovered was mevastatin isolated from the fungus Penicillium citrinum (the same fungus penicillin was discovered from). Mevastatin was thought to act by inhibiting cholesterol formation in the cell membrane of invading bacteria and, thus, in vivo it acts as an antibiotic.

Mevastatin was tested in animals and there was a high rate of liver tumors and muscle damage, and thus it was abandoned. Eventually, lovastatin was isolated from Aspergillus terreus and marketed in 1987 as Mevacor.