This study is being done in adults with familial hypercholesterolaemia, a condition that causes very high levels of cholesterol in the blood. It is looking at atorvastatin, a medicine used to lower cholesterol, and placebo. The purpose of the study is to find out whether muscle symptoms are truly caused by atorvastatin or whether they are linked to other reasons.
The study uses a step-by-step treatment plan. Each person will have periods with atorvastatin, periods with placebo, and a period with no study treatment. The order of these periods is arranged by chance. During the study, muscle symptoms are checked over time to compare how they change during each period.
The study is designed to help understand statin-associated muscle symptoms, which are muscle problems that some people notice while taking statin medicines such as atorvastatin. It also looks at whether some symptoms may be nocebo or misattributed, meaning they are felt as real symptoms but may not be caused by the medicine itself.



Norway