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傳明酸 (Tranexamic Acid)
      傳明酸（Tranexamic Acid 或 Transamin (斷血炎)，又稱氨甲環酸）是一種人工合成的胺基酸，其他名稱有斷血炎、止血環酸、凝血酸等，具有止血抗炎的藥理效果，本作為凝血劑用途，有針劑跟口服兩種用法。
      屬於纖維蛋白溶解抑製藥中的一類，通過可逆性阻斷纖溶酶原分子上的賴氨酸結合位點，導致纖溶酶原不能轉變為纖溶酶，從而有效抑制纖維蛋白溶解、產生止血作用。臨床上廣泛應用於外科、內科、泌尿科和婦產科等領域，治療各種出血性疾病和手術時異常出血等。又因可以抑制黑色素細胞的活性，防止和改善皮膚的色素沉積，因而有一定的美容效果。
藥理
      屬於血液系統用藥、止血與抗纖溶藥、抗纖溶藥。可直接阻礙黑色素細胞活性化，改善黑斑活性化因子群的活躍狀態。
作用機制
      正常情況下，當機體出血時，可先後啟動外源性或內源性凝血系統，同時血管痙攣，血小板激活、黏附、聚集於損傷血管的基底膜，並在局部引起血液凝固，最終形成纖維蛋白凝塊，而產生止血作用。凝血系統激活的同時，抗凝血系統和纖溶系統也被激活，有利於防止凝血過程的擴散和局部血流的再通，保證正常的血液循環。通常凝血、抗凝血、纖溶系統之間，處於動態平衡。
      氨甲環酸與纖溶酶原和纖溶酶的賴氨酸結合位點有高度親和力，能競爭性抑制纖維蛋白的賴氨酸與纖溶酶結合，從而抑制纖維蛋白的裂解，抑制纖溶過程，減少大量出血和複發性出血的可能。其低劑量能抑制纖溶酶原的活化作用，高劑量還能直接抑制纖溶酶的蛋白溶解酶活性，因而止血效果更為顯著。
主要臨床應用
創傷
      研究顯示，氨甲環酸可以安全可靠地降低創傷出血患者的死亡率。 有鑒於此，氨甲環酸這種廉價的、非專利藥物，已經列入了WHO必備藥品清單中，並將在世界高、中、低收入國家中得到廣泛應用。
顱腦創傷
      研究顯示，接受氨甲環酸的顱腦患者發生進行性出血的可能降低，死亡率亦有降低的趨勢。
      儘管這兩項研究均沒有得出十分明確的結論，但仍提示了氨甲環酸有可能改善創傷性腦損傷的預後，這將為後續研究打下基礎，例如即將實施並招募多達10000名顱腦損傷患者的CRASH-3研究，它將為氨甲環酸對於改善死亡率和致殘率的療效方面提供可靠的證據。
經血過多
      氨甲環酸能夠顯著降低經血過多婦女的血量損失。一項評價抗纖溶藥（主要為氨甲環酸）治療經血過多的Cochrane系統評價指出，與安慰劑或其他治療相比，抗纖溶製劑可以更多的降低月經過多婦女的血量損失，同時不增加副反應的發生率。美國食品藥品監督管理局已於2009年11月13日批准將氨甲環酸口服片作為重度經血過多婦女的治療措施。
產後出血
      研究顯示，氨甲環酸使產後出血量顯著地減少。然而由於納入的三個隨機試驗的方法學質量都稍低，目前尚無來自高質量研究的證據支持抗纖溶藥在產後出血的應用。當前，一項名為WOMAN（The World Maternal Antifibrinolytic Trial）的隨機雙盲安慰劑對照試驗正在開展，它將在全球招募15000患者，為早期應用氨甲環酸對於產後出血患者的死亡率、子宮切除率等改善方面提供可靠證據。
外科手術
      一項納入65個隨機對照試驗的Cochrane系統評價指出，氨甲環酸使術後輸血的風險降低了近1/3 (RR 0.61, 95% CI 0.53 to 0.70)， 並減少了術中和術後的出血量，同時血栓栓塞事件的發生率並未增高。
其他治療作用
      氨甲環酸也作為二線方案用於因子Ⅷ缺乏的血友病患者手術前後的輔助治療。並且還可用於遺傳性血管性水腫。
美白效果
      其退黑除斑的功效比維生素C高約50倍，是果酸的近10倍左右。
副作用
      口服過量副作用有腹瀉，性功能障礙，噁心和嘔吐，或是眼花的情形。偶有藥物過量所致顱內血栓形成和出血。較少見的有經期不適（經期血液凝固所致）。由於可進人腦脊液，注射後可有視力模糊、頭痛、頭暈、疲乏等中樞神經系統癥狀，特別與注射速度有關，但很少見。
注意事項
(1).有血栓形成傾向及有心肌梗死傾向者慎用。
(2).慢性腎功能不全時用量酌減，給藥後尿液濃度常較高。治療前列腺手術出血時，用量也應減少。
(3).在美容方面，該成分本身帶有一定的腐蝕性，在體內代謝周期尚未知，需要慎用。尤其注射和點滴存在風險，不宜擅自使用。
藥物相互作用
1.與青霉素或尿激酶等溶栓劑有配伍禁忌。
2.口服避孕藥、雌激素和凝血酶原複合物與本品合用，有增加血栓形成的危險。

商品化
      外敷有使皮膚變白的附加效果，因此早期被皮膚科用在治療肝斑、黑斑沉澱方面的藥用處方籤中，以口服方式每日服用。
      傳明酸已於2005年3月24日經由中華民國衛生署公告為有效美白成分，具美白肌膚、淡化色斑等作用，和現有的維他命C衍生物以及眾多植物萃取相較，除了穩定性更高不受環境以及運送影響外，更目前衛生署已核准使用於美白化粧品中，限量添加2%~3%，美白功效則和一般市面常見的麴酸差不多。而美白針療程也是以傳明酸為主的成分搭配多種維他命，以注射方式快速達到美白方式。
Picture
Tranexamic Acid 250mg - 商品名 Transamin Capsule 250mg (斷血炎 膠囊)
PTT     (2007-2-11) 
 [問題] 禁用止血劑 transamine
今天有個gross hematuria病人就用了transamin
問了住院醫師為什麼要用transamin止血

回答是 : 這病人明天要做膀胱與輸尿管內視鏡
如果內視鏡進去血還流呀流的 應該會造成觀察上的困擾吧~
另外，除了住院醫師說的原因之外 還有
1.內視鏡放進去轉呀攪的 會比較容易出血
2.病人住醫院觀察幾天了hematuria還沒停下來，先將症狀緩和，可以減少家屬的焦慮

關於這個 Transamine 的用法，我一直有個疑問，
:    就是 Bladder bleeding（或是說hematuria的病人），到底要不要用？
:    我看我們醫院的 Urologist 都會用，
:    問題是我看過很多病人，後來就一個大血塊塞在urinary tract，
:    造成 Acute renal failure。

-- transamin...EBM已經証實無效了，但大家還是在用..= = 02/11 21:27
→ jcchiou:止血針這個名詞還是頗有魔力的 XD

(2007-2-8)
E-Medicine : Antifibrinolytic agents, such as aminocaproic acid and tranexamic acid, are
contraindicated as initial therapies for hemophilia-related hematuria
originating from the upper urinary tract because they can cause obstructive
uropathy or anuria.
       我個人的想法，gross hematuria是個sign，治療應該是找underlying，
真的會因為gross hematuria而造成major blood loss的話，那打什麼也沒用....
（如acute bloody stool，有人會只打transmin，而不去找出血源頭嗎？）
       因此，我的感覺是，打transamin，是針對那些虛弱到無法再做任何事的病人，
又為了給家屬一點交代（我們有打止血針，我們有盡力了），
唯一能使用足以安慰的藥....
Tranexamic Acid
       Tranexamic acid is a synthetic analog of the amino acid lysine. It is used to treat or prevent excessive blood loss during surgery and in various other medical conditions. It is an antifibrinolytic that competitively inhibits the activation of plasminogen to plasmin, by binding to specific sites of both plasminogen and plasmin, a molecule responsible for the degradation of fibrin, a protein that forms the framework of blood clots. Tranexamic acid has roughly eight times the antifibrinolytic activity of an older analogue, ε-aminocaproic acid.
Medical uses
      Tranexamic acid is frequently used in surgeries with high risk of blood loss such as cardiac, liver, vascular and large orthopedic procedures. Its oral form is now being evaluated for use in outpatient conditions involving heavy bleeding.
Trauma
      Tranexamic acid has been found to decrease the risk of death in people who have significant bleeding due to trauma. However, it may actually increase the risk of death due to bleeding if administered more than 3 hours after the injury.
Heart surgery
      Tranexamic acid is commonly used in cardiac surgery, both with and without cardiopulmonary bypass. It replaces aprotinin.
Orthopedic surgery
      Tranexamic acid is used in orthopedic surgery to reduce blood loss. It is of proven value in clearing the field of surgery and reducing pre- and postoperative blood loss. Drain and number of transfusions are reduced. However, the hidden blood loss is not reduced. Still, it is becoming an important tool in the anaesthetist's arsenal. It is commonly used in joint replacement surgery.
Craniofacial surgery
      Use of tranexamic acid in surgical corrections of craniosynostosis in children reduces the need for blood transfusions.
Menstrual bleeding
      Used as firstline nonhormonal treatment of dysfunctional uterine bleeding, and heavy bleeding associated with uterine fibroids. An August 2007 study showed patients treated with tranexamic acid are more likely to develop thrombosis and necrosis in their fibroids, and may result in pain and fever. The histological appearance of the necrosis in women treated by tranexamic acid is no different from the spontaneous incidence of thrombosis. The U.S. Food and Drug Administration (FDA) approved tranexamic acid oral tablets (brand name Lysteda) for treatment of heavy menstrual bleeding on 13 November 2009.
       In March 2011 the status of Tranexamic acid for treatment of heavy menstrual bleeding (menorrhagia) was changed in the UK, from PoM (Prescription only Medicines) to P (Pharmacy Medicines) and became available over the counter in UK pharmacies under the brand names of Cyklo-F and Femstrual, initially exclusively for Boots pharmacy, which has sparked some discussion about availability. (In parts of Europe - like Sweden - it had then been available OTC for over a decade.) Regular liver function tests are recommended when using tranexamic acid over a long period of time.
Dentistry
      Tranexamic acid is used in dentistry in the form of a 5% mouth rinse after extractions or surgery in patients with prolonged bleeding time, e.g. from acquired or inherited disorders.
Other uses
      In obstetrics, tranexamic acid is used after delivery to reduce bleeding, often with syntocinon/oxytocin and fundal massage. A major trial is in progress worldwide to establish the efficacy of the drug to arrest postpartum haemorrhage (PPH). Since the drug can be administered orally, it has great potential to reduce maternal mortality rates in developing countries where primary healthcare is often unavailable.
      In cardiac surgery, e.g. coronary artery bypass surgery, it is used to prevent excessive blood loss.
      In hemophilia - Tranexamic acid is also useful in the treatment of bleeding as a second line treatment after factor VIII in patients (e.g. tooth extraction).
In hereditary angioedema
      In melasma - Tranexamic acid has shown to provide rapid and sustained lightening in melasma by decreasing melanogenesis in epidermal melanocytes.
      In hyphema - Tranexamic acid has been shown to be effective in reducing risk of secondary hemorrhage outcomes in patients with traumatic hyphema.
Adverse effects
      Rare in general, including gastrointestinal effects, dizziness, fatigue, headache, and hypersensitivity reactions. Use of tranexamic acid has a potential risk of thrombosis.