Chapter Six · Statins and muscle
Usually it is nothing much. Occasionally it is the beginning of something that damages the kidneys, and one cheap blood test tells them apart.
Start with a phone call. Your doctor’s office has a triage line and a nurse will talk it through with you. They are good at this, they do it all day, and it costs nothing. You ring the main number and ask for the triage nurse. There is no charge and you do not need an appointment.
If it feels more serious than that, go to urgent care. You will usually be seen faster than at a hospital.
If it feels life-threatening — chest pain, trouble breathing, confusion, no urine at all for a day — call 911 or go to the emergency room. Do not wait until you are sure. Take the more cautious road.
Rather listen?
Takes about 7 minutes, read aloud. It is the same words as the page below, so nothing is missing if you would rather read. Download it to keep on your phone — it will play with no signal, in a waiting room or a car.
Muscle aching on a statin is common and usually mild. It is worth reporting
rather than enduring, because there are several statins and the alternatives often suit
better.
→ where this is explained: The common version
There is a rare, serious version. Muscle breaks down, and the material released
has to be cleared by the kidneys. That is what makes it dangerous.
→ where this is explained: The version that matters
Kidney function changes the risk. If the kidneys are already not clearing well,
the drug can build up — which is why this chapter sits next to
Chapter One.
→ where this is explained: Why the kidneys matter here
Tick the ones that apply. The bar below shows how much they add up to.
What we would do, as a friend rather than as your doctor. This is our opinion and we stand behind it. It is not medical advice and we are not examining you.
It is not a one-time reading. If you start feeling worse while you are deciding, move up a level. Nobody has ever been criticised for turning up and being sent home. A false alarm is the best possible outcome here.
If none of these apply, the rest of this chapter is worth your time. Take it slowly; there is no clock on it.
Aching, tenderness or weakness, often in the thighs, shoulders or the muscles you use climbing stairs. It is one of the commonest reasons people stop taking a statin, and it is worth saying out loud rather than quietly stopping — because the drug is doing something useful, and because there are several of them.
Practical points: dose can be changed, the statin can be changed, and the timing can be changed. Stopping without saying so removes both the side effect and the benefit, and nobody learns anything.
Rarely, muscle tissue breaks down rather than simply aching. The contents of the muscle cells enter the bloodstream, and the kidneys have to clear them. That clearing is what harms the kidney.
The word for it is rhabdomyolysis, and it is worth knowing because saying it tends to get the right test ordered. The signs are severe muscle pain or weakness, sometimes with dark urine.
The test is cheap, quick and available everywhere: CK, creatine kinase, a single blood test. It is high when muscle is breaking down. If you have muscle symptoms on a statin, this is the reasonable thing to ask for.
Statins leave the body by routes that depend on the liver and kidneys working. Where kidney function has fallen, the drug can reach a higher level than intended, and the risk of the serious muscle problem rises with it.
That creates a loop worth seeing whole: reduced kidney function raises the risk of muscle breakdown, and muscle breakdown damages the kidney further. Each half is ordinary medicine. The loop is what does the harm, and it is only visible if somebody is looking at both halves at once.
Grade B There is a second effect worth knowing. Creatinine — the blood test most kidney estimates are calculated from — is a waste product of muscle. Someone who has lost muscle produces less of it, so the kidney estimate can read better than the kidneys actually are. Losing muscle and having kidney function overestimated can happen at the same time, for the same reason. Chapter One covers that.
“I have muscle aching since starting this. Can we check a CK?”
“What is my kidney function, and does it change which statin or which dose is right for me?”
“Is there anything else I am taking that interacts with this one?”
“If we stop it, what are we giving up, and what would we use instead?”
Back to the contents.
Written from the general clinical literature. Nothing on this page comes from any individual’s medical record. Statements resting on evidence that is established rather than universal carry a grade.