CYP2D6基因型为什么会同时影响可待因和他莫西芬的用药安全？
Why does CYP2D6 genotype affect the safety of both codeine and tamoxifen?
可待因本身镇痛作用弱，需经CYP2D6转化为吗啡才有效：超快代谢者体内吗啡浓度骤升，可能出现呼吸抑制，婴幼儿和哺乳期用药风险尤为突出，而慢代谢者则几乎无镇痛效果。他莫西芬情况类似但方向相反，它需要CYP2D6活化为内昔芬才发挥抗雌激素作用，慢代谢者或同时服用强效CYP2D6抑制剂（如某些SSRI类抗抑郁药）者活性代谢物不足，疗效可能下降。相应用药指南建议根据代谢表型换药或调整方案。
Codeine itself is a weak analgesic and must be converted by CYP2D6 into morphine: ultrarapid metabolisers can develop dangerously high morphine levels with respiratory depression, a particular concern in infants and during breastfeeding, while poor metabolisers get almost no pain relief. Tamoxifen shows the mirror image, since CYP2D6 activates it to endoxifen for its antioestrogen effect, so poor metabolisers or patients taking strong CYP2D6 inhibitors such as certain SSRIs may generate too little active metabolite and lose efficacy. Pharmacogenetic guidelines therefore recommend switching drugs or adjusting therapy according to metaboliser phenotype.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
杨宝峰 主编,《药理学》第9版,人民卫生出版社,2018
Yang Baofeng ed., Pharmacology, 9th ed., PMPH, 2018
独立核验依据 · Independent verification: 核验依据 2 ISBN 9787117266048（豆瓣书目条目: 药理学）
#CYP2D6 #可待因 #他莫西芬
使用卡马西平前为什么建议检测HLA-B*15:02？
Why is HLA-B*15:02 testing advised before starting carbamazepine?
携带HLA-B*15:02的个体，其HLA分子能异常呈递卡马西平相关抗原并激活细胞毒性T细胞，显著提高Stevens-Johnson综合征和中毒性表皮坏死松解症等重症药疹的风险，而该等位基因在部分亚洲人群中携带率较高。前瞻性研究显示，对筛查阳性者改用其他抗癫痫药物，可大幅减少这类致命性皮肤反应的发生。中国相关用药指南已推荐在高风险人群使用该药前进行基因检测。
In carriers of HLA-B*15:02, the HLA molecule presents carbamazepine-related antigens abnormally and activates cytotoxic T cells, sharply raising the risk of severe cutaneous reactions such as Stevens-Johnson syndrome and toxic epidermal necrolysis, and this allele is relatively common in some Asian populations. Prospective studies showed that switching screen-positive patients to alternative antiepileptic drugs greatly reduced these potentially fatal reactions. Chinese prescribing guidance now recommends genotyping before use in high-risk populations.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 来源待核验 · Source pending review
来源 · Source
出处备注：著录含书名，但缺版次 / 出版社 / 年份中的一部分，需编辑补全后才能做独立比对。
《新英格兰医学杂志》(NEJM)（Chen 等，卡马西平所致重症药疹与HLA-B*1502筛查，2011）
NEJM (Chen et al., carbamazepine-induced toxic effects and HLA-B*1502 screening, 2011)
#HLA-B*15:02 #卡马西平 #重症药疹
华法林的剂量为什么个体差异如此之大？
Why does the required warfarin dose vary so much between individuals?
华法林主要由CYP2C9代谢，携带*2、*3等功能减弱等位基因者清除变慢，达到相同抗凝强度所需剂量更低；其作用靶点维生素K环氧化物还原酶由VKORC1编码，启动子区变异影响酶表达水平和药物敏感性，两者合计可解释相当一部分剂量差异。基因型指导给药在随机试验中改善了治疗初期INR位于目标范围内的时间，但对出血和血栓这类硬终点的获益有限。临床上仍以INR监测为核心，同时注意维生素K摄入和合并用药的影响。
Warfarin is metabolised mainly by CYP2C9, and reduced-function alleles such as *2 and *3 slow clearance so lower doses achieve the same anticoagulation; its target, vitamin K epoxide reductase encoded by VKORC1, has promoter variants that change enzyme expression and drug sensitivity, and together these genes explain a substantial share of dose variability. Genotype-guided dosing improved time in therapeutic INR range during initiation in randomised trials, but gains on hard endpoints such as bleeding and thrombosis were limited. Care still centres on INR monitoring, with attention to vitamin K intake and interacting medications.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 来源待核验 · Source pending review
来源 · Source
出处备注：著录含书名，但缺版次 / 出版社 / 年份中的一部分，需编辑补全后才能做独立比对。
《新英格兰医学杂志》(NEJM)（EU-PACT 华法林基因型指导给药试验，2013）
NEJM (EU-PACT trial of genotype-guided warfarin dosing, 2013)
#华法林 #CYP2C9与VKORC1 #INR监测
为什么CYP2C19慢代谢者按常规剂量服用氯吡格雷时，抗血小板疗效会明显减弱？
Why does standard-dose clopidogrel lose much of its antiplatelet effect in CYP2C19 poor metabolizers?
氯吡格雷本身无活性，须在肝内经CYP2C19催化的两步氧化生成含巯基的活性代谢物，后者不可逆地阻断血小板P2Y12受体而抑制聚集。携带功能缺失等位基因的慢代谢者生成的活性代谢物减少，血小板抑制不足，接受冠脉支架治疗后血栓事件风险上升。CPIC指南建议此类患者换用无需CYP2C19活化的替格瑞洛或普拉格雷。
Clopidogrel is inert until it undergoes two oxidative steps catalyzed mainly by hepatic CYP2C19, yielding a thiol metabolite that irreversibly blocks the platelet P2Y12 receptor and prevents aggregation. Poor metabolizers carrying loss-of-function alleles form little active metabolite, show insufficient platelet inhibition, and face higher thrombotic risk after coronary stenting. CPIC guidance advises switching them to ticagrelor or prasugrel, neither of which requires CYP2C19 activation.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-11-03
来源 · Source
Scott SA 等. CPIC指南：CYP2C19基因型与氯吡格雷治疗（2013更新）. Clinical Pharmacology & Therapeutics, 2013 (DOI:10.1038/clpt.2013.105)
Scott SA, et al. CPIC Guideline for CYP2C19 genotype and clopidogrel therapy: 2013 update. Clinical Pharmacology & Therapeutics, 2013 (DOI:10.1038/clpt.2013.105)
独立核验依据 · Independent verification: 核验依据 1 CROSSREF 标识 10.1038/clpt.2013.105：Clinical Pharmacogenet
#氯吡格雷 #药物基因组学 #CYP2C19 #前体药物
药物基因组学到底研究什么？
What does pharmacogenomics actually study?
它研究遗传变异如何影响药物的吸收、代谢、转运和靶点反应，从而解释为什么相同剂量在不同人身上疗效和不良反应差别很大。常见应用是在用药前检测代谢酶基因型或特定HLA等位基因，预测疗效不足、剂量需求异常或严重过敏风险，并据此换药或调整剂量。需要注意的是基因只解释部分个体差异，年龄、肝肾功能、合并用药、饮食和服药依从性同样重要。
Pharmacogenomics studies how genetic variation affects drug absorption, metabolism, transport and target response, explaining why the same dose produces very different efficacy and side effects across people. A common application is testing metabolising enzyme genotypes or specific HLA alleles before prescribing, to predict poor response, unusual dose requirements or serious hypersensitivity risk, and then switching drugs or adjusting doses. Genetics explains only part of the variability, since age, liver and kidney function, co-medication, diet and adherence matter as well.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
杨宝峰 主编,《药理学》第9版,人民卫生出版社,2018
Yang Baofeng ed., Pharmacology, 9th ed., PMPH, 2018
独立核验依据 · Independent verification: 核验依据 2 ISBN 9787117266048（豆瓣书目条目: 药理学）
#药物基因组学 #代谢酶基因型 #个体化用药
为什么服某些药时会被提醒不要喝葡萄柚汁？
Why are patients told to avoid grapefruit juice with certain medicines?
葡萄柚汁中的呋喃香豆素类成分会不可逆抑制小肠壁的CYP3A4酶，使经该酶代谢的药物首过消除减少、血药浓度升高，从而放大不良反应，例如部分他汀类药物的肌肉损伤和某些钙通道阻滞剂引起的低血压。由于是酶被灭活后需重新合成，影响可持续一天以上，单纯错开服药时间并不可靠。一般建议服用相关药物期间避免葡萄柚及其果汁，具体以药品说明书和药师建议为准。
Furanocoumarins in grapefruit juice irreversibly inhibit CYP3A4 in the intestinal wall, so drugs metabolised by that enzyme undergo less first-pass elimination and reach higher blood levels, amplifying adverse effects such as muscle injury with some statins or hypotension with certain calcium channel blockers. Because the enzyme must be resynthesised, the effect can last more than a day, so simply separating the juice from the dose is unreliable. It is generally advised to avoid grapefruit and its juice while taking such drugs, following the product label and pharmacist advice.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 来源待核验 · Source pending review
来源 · Source
出处备注：著录含书名，但缺版次 / 出版社 / 年份中的一部分，需编辑补全后才能做独立比对。
《英国临床药理学杂志》(Bailey 等，葡萄柚汁与药物相互作用综述，1998)
British Journal of Clinical Pharmacology (Bailey et al., review of grapefruit juice-drug interactions, 1998)
#CYP3A4 #药物相互作用 #葡萄柚汁
化疗前检测DPYD和UGT1A1有什么意义？
What is the point of DPYD and UGT1A1 testing before chemotherapy?
氟嘧啶类药物如5-氟尿嘧啶和卡培他滨主要由DPD酶降解，DPYD功能缺失变异携带者体内药物蓄积，容易出现严重骨髓抑制、黏膜炎、腹泻甚至致死性毒性；伊立替康的活性代谢物SN-38需经UGT1A1葡糖醛酸化清除，UGT1A1*28或*6变异者中性粒细胞减少和严重腹泻风险明显增加。前瞻研究显示按基因型预先减量可显著降低严重毒性，而疗效未见明显牺牲。因此多国指南已推荐相关药物使用前进行基因筛查。
Fluoropyrimidines such as 5-fluorouracil and capecitabine are degraded mainly by DPD, so carriers of DPYD loss-of-function variants accumulate drug and are prone to severe myelosuppression, mucositis, diarrhoea and even fatal toxicity; irinotecan's active metabolite SN-38 is cleared by UGT1A1 glucuronidation, and UGT1A1*28 or *6 carriers face markedly higher risks of neutropenia and severe diarrhoea. Prospective studies show that genotype-guided dose reduction substantially lowers severe toxicity without clearly compromising efficacy. Guidelines in several countries now recommend testing before these drugs are given.
难度 进阶 · 适合 大众
CC BY 4.0 · 来源待核验 · Source pending review
来源 · Source
出处备注：此条未指向带版次的可引用著作（通识性内容、机构文件或未展开的英文书名），本库不提供独立书目出处；如需精确引用，需由编辑补全具体篇目与版次。
The Lancet Oncology（Henricks 等，DPYD基因型指导氟嘧啶剂量研究，2018）
The Lancet Oncology (Henricks et al., DPYD genotype-guided dose individualisation of fluoropyrimidines, 2018)
#DPYD #UGT1A1 #化疗毒性预测
阿司匹林口服后的血浆半衰期只有十几分钟，为什么用作抗血小板治疗时每天只需服一次小剂量？
Aspirin’s plasma half-life after a dose is under twenty minutes — why is one small daily dose sufficient for antiplatelet therapy?
小剂量阿司匹林不可逆地乙酰化血小板环氧合酶-1，阻断促聚集的血栓素A2生成。血小板没有细胞核，无法重新合成该酶，功能抑制须待骨髓新生血小板更替才解除，约需7～10天，故单次给药的抗栓作用远超其血浆半衰期。加之门静脉首过使小剂量即可优先作用于肝前血流的血小板，对全身前列环素合成影响较小，每日一次小剂量方案由此确立。
Low-dose aspirin irreversibly acetylates platelet cyclooxygenase-1, shutting off production of the pro-aggregatory messenger thromboxane A2. Platelets have no nuclei and cannot resynthesize the enzyme, so inhibition persists until newly formed platelets replace the blocked ones over roughly 7–10 days — far outlasting aspirin’s own plasma half-life. Presystemic portal exposure also lets a small dose act preferentially on platelets before hepatic clearance, sparing systemic prostacyclin synthesis, which is precisely why once-daily low-dose regimens work.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-11-02
来源 · Source
Patrono, C. 等《低剂量阿司匹林预防动脉粥样硬化性血栓形成》，《新英格兰医学杂志》（New England Journal of Medicine）353卷22期，2005年，DOI:10.1056/NEJMra052717
Patrono, C. et al., “Low-Dose Aspirin for the Prevention of Atherothrombosis”, New England Journal of Medicine, 353(22), 2005, DOI:10.1056/NEJMra052717
独立核验依据 · Independent verification: 核验依据 1 CROSSREF 标识 10.1056/nejmra052717：Low-Dose Aspirin for th
#临床药理学 #阿司匹林 #环氧合酶-1 #抗血小板治疗
为什么所有患者在使用阿巴卡韦前都必须检测HLA-B*57:01？该等位基因引起致死性超敏反应的免疫学机制是什么？
Why must every patient be screened for HLA-B*57:01 before starting abacavir, and what immunologic mechanism makes this allele cause life-threatening hypersensitivity?
HLA-B*57:01阳性者服阿巴卡韦可发生致命性多系统超敏反应。按“改变肽库”模型，药物结合于B*57:01分子抗原结合槽，改变其呈递的内源性肽谱，T细胞将自身肽-HLA复合物误认作异物，活化药物特异性CD8+ T细胞而致病。PREDICT-1试验证实前瞻性筛查几乎消除了临床疑似病例，指南因此要求用药前必检。
Carriers of HLA-B*57:01 risk fatal multisystem hypersensitivity when given abacavir. In the altered-peptide-repertoire model, the drug binds into the antigen-binding groove of B*57:01 and reshapes the repertoire of endogenous peptides presented, so T cells mistake self peptide-HLA complexes for foreign ones and drug-specific CD8+ T cells attack host tissues. The PREDICT-1 randomized trial showed prospective screening almost eliminates clinically suspected cases, so international guidelines mandate testing before prescribing.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 来源待核验 · Source pending review
来源 · Source
出处备注：著录含书名，但缺版次 / 出版社 / 年份中的一部分，需编辑补全后才能做独立比对。
Mallal S等，PREDICT-1试验，《新英格兰医学杂志》(N Engl J Med) 2008年358卷
Mallal S, et al. HLA-B*5701 screening for hypersensitivity to abacavir (PREDICT-1). N Engl J Med. 2008;358(6):568-579.
#药物基因组学 #HLA-B*57:01 #阿巴卡韦 #超敏反应
同样是心脏支架术后的患者，为什么有人按常规剂量服用氯吡格雷仍然发生支架内血栓？
Why do some heart-stent patients develop stent thrombosis even while taking the routine dose of clopidogrel?
氯吡格雷是无活性前药，须经肝脏CYP2C19等酶分步转化为活性代谢物，才能不可逆地封闭血小板ADP受体。携带功能缺失等位基因（如*2、*3）者活化效率显著下降，血小板抑制不足，支架内血栓与缺血事件风险升高。TRITON-TIMI 38等研究支持基因检测指导选药，此类患者常改用不依赖该酶的替格瑞洛或普拉格雷。
Clopidogrel is an inactive prodrug that must undergo stepwise conversion by hepatic enzymes, chiefly CYP2C19, before its active metabolite can irreversibly block platelet ADP receptors. Carriers of loss-of-function alleles such as *2 or *3 generate far less active metabolite, leaving platelets under-inhibited and raising the risk of stent thrombosis and ischemic events. Evidence including TRITON-TIMI 38 supports genotype-guided drug selection; these patients are often switched to ticagrelor or prasugrel, whose activation does not hinge on CYP2C19.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-11-03
来源 · Source
Mega JL 等．细胞色素P450多态性与氯吡格雷反应．《新英格兰医学杂志》，2009；360(4)：354-362；DOI:10.1056/NEJMoa0809171
Mega JL, et al. Cytochrome P-450 polymorphisms and response to clopidogrel. N Engl J Med. 2009;360(4):354-362; DOI:10.1056/NEJMoa0809171
独立核验依据 · Independent verification: 核验依据 1 CROSSREF 标识 10.1056/NEJMoa0809171：Cytochrome P-450 Polym
#药物基因组学 #氯吡格雷 #CYP2C19 #个体化医疗