Statin induced myopathy

In their article regarding statin induced myopathy, Sathasivam and
Lecky mention that “lipophilic statins (for example simvastatin,
atorvastatin, lovastatin) are more likely to produce muscular effects than
are relatively hydrophilic agents (such as pravastatin, rosuvastatin and
fluvastatin)”.

However, another important property is that simvastatin, atorvastatin
and lovastatin are metabolised by the hepatic cytochrome P450 3A4 (CYP3A4)
enzyme system whereas pravastatin, fluvastatin and rosuvastatin do not
rely upon CYP3A4. This is especially important in the increasing number of
patients with a renal transplant (and other transplants and other
conditions) receiving immunosuppressive drugs and also requiring a statin.
CYP3A4 is also responsible for the metabolism of ciclosporin, tacrolimus
and sirolimus. Ciclosporin was included in box 1 of the article
highlighting potential interactions with concomitant use of statins.
Increased levels of statins have been reported when coadministered with
ciclosporin increasing the risk of myopathy.

According to the respective summary of product characteristic, the
maximum dose of the statin when used together with ciclosporin is as
follows: simvastatin 10mg, atorvastatin 10mg, pravastatin start with 20mg
and increase to 40mg, fluvastatin caution is advised. Rosuvastatin is
contraindicated with ciclosporin.

This is especially important since therapeutic substitutions to a
cheaper statin are a frequent occurrence, both in an inpatient and
community setting, with potentially serious consequences.

Competing interests:
None declared