2. TRIAL DESIGN i) Randomised, double blind, placebo controlled N-of-1 trial ii) Patients who have stopped or are considering discontinuation of their statin due to muscle symptoms iii) Once-daily oral administration of Atorvastatin (20mg) or placebo iv) Study treatment is 12-months v) IMP in 2-month treatment periods vi) Quantify the occurrence of self-reported muscle symptoms vii) 200 patients will be recruited.