{"gene":{"symbol":"SLCO1B1","name":"Solute Carrier Organic Anion Transporter Family Member 1B1","protein":"Organic anion-transporting polypeptide 1B1 (OATP1B1)","ncbi_gene_id":"10599","locus":"12p12.1","summary":"SLCO1B1 encodes the liver uptake transporter OATP1B1, which moves statins and other drugs from the blood into hepatocytes. A common reduced-function variant, rs4149056 (c.521T>C, the *5 allele), lets statins build up in blood and muscle instead, raising the risk of statin-induced muscle pain (myopathy), most strongly with simvastatin. SLCO1B1 affects statin tolerability, not whether the statin lowers cholesterol.","function":"Unlike CYP enzymes, SLCO1B1 does not break down drugs — it transports them. The OATP1B1 protein sits on the surface of liver cells and ferries statins (and other organic anions, including some chemotherapy and antibiotic drugs) from the blood into the hepatocyte; statins act in the liver, and efficient uptake keeps blood and muscle concentrations low. When OATP1B1 function is reduced, systemic exposure rises and more drug reaches skeletal muscle, where statin toxicity shows up as aches, weakness and, rarely, rhabdomyolysis. CPIC 2022 describes increased exposure to each statin it covers when SLCO1B1 function is reduced and gives statin-specific recommendations; for simvastatin and lovastatin it recommends an alternative statin in decreased and poor function.","category":"pharmacogene","key_variants":[{"rsid":"rs4149056","name":"*5 / *15 (c.521T>C, V174A)","alleles":"Plus strand, GRCh37 (as in 23andMe raw data): T reference, C variant (c.521T>C, Val174Ala), found in *5 and *15.","effect":"The C allele reduces OATP1B1 activity. In the SEARCH study (simvastatin 80 mg), odds of myopathy were ~4.5x higher per C allele, and C/C carriers had ~17x the odds compared with T/T.","frequency_note":"C allele ~15% in Europeans; lower in East Asians and some African groups, higher in Amerindian populations."}],"phenotypes":["Increased function (*14/*14)","Normal function (e.g. *1/*1, *1/*14; rs4149056 T/T)","Decreased function (one no-function allele, e.g. *1/*5, *1/*15; rs4149056 T/C)","Possible decreased function (one no-function plus one uncertain-function allele)","Poor function (two no-function alleles, e.g. *5/*5, *5/*15, *15/*15; rs4149056 C/C)","Indeterminate"],"clinical_relevance":"SLCO1B1 has a peer-reviewed CPIC guideline (first published 2012, updated 2014; replaced in 2022) for statin-associated muscle symptoms. CPIC 2022 recommends an alternative statin for decreased- and poor-function phenotypes on simvastatin, and limits simvastatin to <20 mg/day if it is still used in decreased function; separately, the FDA label sets a 40 mg/day maximum and restricts 80 mg to long-term users without muscle toxicity. The 2022 guideline covers atorvastatin, pitavastatin, rosuvastatin, pravastatin, fluvastatin and lovastatin with genotype-specific recommendations (e.g., poor function: starting doses of ≤20 mg atorvastatin, ≤1 mg pitavastatin, ≤20 mg rosuvastatin, ≤40 mg pravastatin or fluvastatin, and an alternative to lovastatin), and adds ABCG2 (rosuvastatin) and CYP2C9 (fluvastatin). The association comes from a genome-wide study (the SEARCH trial, NEJM 2008) and has been replicated many times; it is one of the best-established pharmacogenomic signals outside the CYP genes. The risk applies to statin tolerability, not cardiovascular benefit, and a genotype is information to discuss with a clinician, not a reason to stop a statin.","consumer_array_caveat":"One of the friendliest pharmacogenes for consumer raw data: rs4149056 is almost always genotyped and nearly all of the known signal is at that one SNP, but a raw-file count is not a CPIC function phenotype, which needs a validated test. Rarer SLCO1B1 alleles and structural variants are not captured.","drugs":[{"drug":"simvastatin","guideline":"CPIC","level":"CPIC A","summary":"CPIC 2022 recommends an alternative statin for SLCO1B1 decreased- and poor-function phenotypes; for decreased function, if simvastatin is still warranted, the dose is limited to <20 mg/day (strong recommendations). In the SEARCH study (simvastatin 80 mg), odds of myopathy were ~4.5x per rs4149056 C allele and ~17x for C/C versus T/T. Independently of genotype, the FDA label sets a 40 mg/day maximum and restricts 80 mg to long-term users without muscle toxicity."},{"drug":"atorvastatin","guideline":"CPIC","level":"CPIC A","summary":"CPIC 2022: for SLCO1B1 decreased function, a starting dose of ≤40 mg; for poor function, a starting dose of ≤20 mg, with rosuvastatin or combination therapy considered if more is needed (moderate recommendations)."},{"drug":"pitavastatin","guideline":"CPIC","level":"CPIC A","summary":"CPIC 2022: for SLCO1B1 decreased function, a starting dose of ≤2 mg; for poor function, a starting dose of ≤1 mg; if a higher dose is needed, an alternative statin or combination therapy (moderate recommendations)."},{"drug":"rosuvastatin","guideline":"CPIC","level":"CPIC A","summary":"CPIC 2022: for SLCO1B1 decreased function, the desired starting dose, with possible increased myopathy risk especially above 20 mg (strong); for poor function, a starting dose of ≤20 mg, with combination therapy if more is needed (moderate). ABCG2 genotype also modifies the rosuvastatin recommendation."},{"drug":"pravastatin","guideline":"CPIC","level":"CPIC A","summary":"CPIC 2022: for SLCO1B1 decreased function, the desired starting dose, with possible increased myopathy risk especially above 40 mg/day; for poor function, a starting dose of ≤40 mg (moderate recommendations)."},{"drug":"fluvastatin","guideline":"CPIC","level":"CPIC A","summary":"CPIC 2022: for SLCO1B1 decreased function, the desired starting dose, with possible increased myopathy risk especially above 40 mg/day; for poor function, a starting dose of ≤40 mg/day (moderate, with normal CYP2C9 function). CYP2C9 genotype also modifies the fluvastatin recommendation."},{"drug":"lovastatin","guideline":"CPIC","level":"CPIC A","summary":"CPIC 2022 recommends an alternative statin for SLCO1B1 decreased- and poor-function phenotypes; for decreased function, if lovastatin is still warranted, the dose is limited to ≤20 mg/day (moderate recommendations)."}],"sources":[{"label":"CPIC — SLCO1B1 gene page","url":"https://cpicpgx.org/gene/slco1b1/"},{"label":"PharmGKB SLCO1B1 (PA134865839)","url":"https://www.pharmgkb.org/gene/PA134865839"},{"label":"NCBI Gene 10599","url":"https://www.ncbi.nlm.nih.gov/gene/10599"},{"label":"Cooper-DeHoff et al., Clin Pharmacol Ther 2022 (CPIC SLCO1B1/ABCG2/CYP2C9–statin guideline)","url":"https://pubmed.ncbi.nlm.nih.gov/35152405/"},{"label":"SEARCH Collaborative Group (Link et al.), N Engl J Med 2008 (SLCO1B1 GWAS, simvastatin myopathy)","url":"https://pubmed.ncbi.nlm.nih.gov/18650507/"},{"label":"ZOCOR (simvastatin) prescribing information, FDA/DailyMed (section 2.1, dosage limits)","url":"https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=8f55d5de-5a4f-4a39-8c84-c53976dd6af9"}],"related_blog":"/blog/pharmacogenomics-europe-guide/","disclaimer":"Educational information only, not medical advice or diagnosis. Consult a clinician before acting on genetic information."},"meta":{"disclaimer":"Educational information only, not medical advice or diagnosis. Consult a clinician before acting on genetic information.","api_version":"2026-09-20","docs":"https://deepdna.ai/docs/","status":"live","data_as_of":"2026-10-25T21:32:19.251Z","freshness":"https://deepdna.ai/api/v1/freshness"}}