Why are CPK and SGPT monitored while giving statins?

Why are CPK and SGPT monitored while giving statins?

Statins are a group of medicines used for lowering cholesterol levels and they have many beneficial effects. Two potential adverse effects of statins are muscle damage and liver injury. Elevation of SGPT indicates liver injury and elevation of CPK suggests muscle damage. The cut off values of importance are SGPT more than three times the upper limit of normal (ULN) and CPK ten times the ULN. Statins can very rarely cause significant liver injury and muscle injury. The latter can very rarely cause myoglobinuria and kidney failure.

CPK monitoring is mostly done only when there are muscle symptoms rather than as routine monitoring