Could a common cholesterol drug ease chronic diarrhoea?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * age 18 years or above * Self-identification as White * Confirmed moderate-severe bile acid diarrhoea with a SeHCAT test result of ≤ 10 % * Reported number of average daily stools ≥ 3 stools per day * Reported number of average daily watery (6 or 7 on the Bristol Stool Chart) stools ≥ 1 stools per day(30) * Informed and written consent Exclusion Criteria: * Unwillingness to pause any of the following medications during the trial: bile acid sequestrants, morphine medication, liraglutide or anti-constipation medication (e.g., lactulose, laxoberal, magnesia) * Unwillingness to pause any anti-diarrhoea medication (e.g., imodium) from 3 days before initiation of each stool diary until after the respective visit * If regularly administering psyllium or metformin, unwillingness to agree to a stable dose of psyllium or metformin throughout the trial * Concomitant use of any drug in the GLP-1 receptor agonist drug class with the exception of paused liraglutide, see above * Concomitant use of any kind of insulin medication * Planned major changes in food consumption throughout the trial, including planned weight loss attempts * Prior use of any statin within the recent 6 months * Intake of larger quantities of grapefruit juice during trial participation, at the discretion of the investigator * History of/present hepatobiliary disorder (except for simple metabolic dysfunction-associated fatty liver disease) and/or alanine aminotransferase and/or serum aspartate aminotransferase ≥ 3 times upper limit of normal * Crohn's disease, ulcerative colitis, celiac disease or lactose intolerance * Previous intestinal resection or major intra-abdominal surgery incl. stoma (cholecystectomy and appendectomy not included) * Nephropathy with estimated glomerular filtration rate \< 45 ml/min/1,73 m2 * Plasma level of creatine kinase ≥ 5 times the upper limit of normal * A recent stroke or transient ischemic attack (within 6 months) * Any treatment or condition requiring acute or subacute medical or surgical intervention * Hypothyroidism or hyperthyroidism, if not well regulated, at the discretion of the investigator * Active or recent (within 6 months) clinically significant malignant disease (non-melanoma skin cancer not included), at the discretion of the investigator * Alcohol consumption exceeding 12 units/week for women or 18 units/week for men, respectively. These thresholds are based on the limits of the European Association for the Study of the Liver * Drug abuse, at the discretion of the investigator * Fertile women not using any of the following contraceptive methods for the duration of the trial until at least 5 days after end of trial: Hormonal (tablet/pill, depot injection of progesterone, subdermal gestagen implantation, hormone intrauterine devices (IUD), hormonal vaginal ring or transdermal hormonal patch) associated with inhibition of ovulation, chemical (copper IUD), sterilisation, vasectomised partner with a confirmatory test, or sexual abstinence per the investigator's discretion * Pregnant or nursing women * Known or suspected hypersensitivity to atorvastatin or any of the additives in the tablet * Receipt of any investigational drug within 30 days prior to visit 0 * Concomitant treatment with any of the following (topical administration not included): ciclosporin, telithromycin, clarithromycin, delavirdin, stiripentol, ketoconazol, voriconazol, itraconazol, posaconazol, letermovir, ritonavir, lopinavir, atazanavir, indinavir, darunavir, bocepravir, telaprevir, elbasvir/grazoprevir, ledipasvir/sofosbuvir, erythromycin, niacin, ezetimibe, fusidic acid, gemfibrozil, colchicine, digoxin, warfarin * Unable to speak or understand Danish or mental incapacity that preclude adequate understanding or cooperation or unwillingness to comply with trial requirements * Active participation in any other clinical intervention trial (observational studies not included) * Other concomitant disease or treatment that according to the investigator's assessment makes the person unsuitable for study participation