96．华法林

出处：按学科分类—医药、卫生 军事医学科学出版社《临床常用进口药物手册》第538页（4376字）

【中文释文】：

蓝色片剂：每片含3mg华法林钠

红色片剂：每片含5mg华法林钠

〔概述〕

华法林是一种合成香豆素药，它抑制在肝里合成的凝血酶原，及干扰因子Ⅶ，Ⅸ及X，所以减少血管内凝血抑制凝血酶原是有赖于干扰维生素K的作用，及有假定华法林类似双香豆素和维生素K竞争合成凝血酶原所必需的酶。

华法林迅速被肠胃吸收，在2～8h可达血浆最高浓度，36～72h达最高效果，在服用单一治疗剂量下其作用在凝血酶原时间可维持约4～5d。

〔适应证〕

预防及治疗肺栓塞及静脉血栓形成

〔剂量及用法〕

剂量必须个别化及要经常监测凝血酶原，时间直至确立维持剂量止。一般情形下，开始剂量约30～50mg，2～5mg作为维持剂量，总剂量可每日1次服用。

要记住此药起效时间为服药后30h。

〔禁忌证〕

在发生出血或有出血倾向、血质不调、紫癜、暴露溃疡性伤口、创伤性或手术性伤口、肠胃溃疡、内脏癌、憩室炎、结肠炎或恶急性细菌性心内膜炎、紧迫流产、近期眼部、脑部或脊柱手术、局部及腰部麻醉、维生素K缺乏、严重高血压、严重肝或肾病、及常有连续性食管及尿道管道引流。

〔副反应〕

高量可能引起血尿，粘膜出血，伤口出血或溃疡性损害或大量瘀点及紫癜性出血，曾报道由粘膜下层或器官内壁出血引起瘫痪性肠梗阻及小肠阻塞，大量子宫出血曾发生，但月经一般正常，口服香豆素抗凝血剂治疗后出血并不经常与凝血酶原活动有关连。

除了出血及出血表现，稀有报道有皮肤炎、荨麻疹及秃头，其他较少有报道副作用包括发热及肠胃不适，如恶心及呕吐以至腹部痉挛及腹泻。口服抗凝血剂治疗曾有报道与妇女乳房及其他部位的出血性坏死(皮肤及皮下组织出血引起坏死，血管炎及血栓形成)。

〔药物交叉作用〕

同时服用水杨酸或其衍生物可能增加出血倾向。

〔生产厂家〕

芬兰埃斯波奥利安药厂

(附本品别名：苯丙酮香豆素钠，苄丙酮香豆素钠，Marevan)。

【外文释文】：

(Blue)：each tablet contains 3 mg of warfarin sodium

Warfarin tablets 5 mg

(Red)：each tablet contains 5 mg of warfarin sodium

Description

Warfarin is a synthetic drug which depresses synthesis of prothrombin in the liver，and interferes with the production of factors Vll，Ⅸ and X，thereby minimizing intravascular clotting．The inhibition of prothrombin involves interference with the action of vitamin K，and it has been postulated that warfarin，like bishydroxycoumarin，competes with vitamin K for an enzyme essential for prothrombin synthesis．Warfarin is readily absorbed from the gastrointestinal tract．Maximal plasma levels are achieved within 2-8 hours，peak effect in 36 to 72 hours，with effects on prothrombin time persisting for about 4-5 days following a single therapeutic dose．

Indications

For the prophylaxis and treatment of pulmonary embolism and venous thrombosis．

Dosage and administration

Dosage must be individualized with frequent prothrombin times being used as a guide until maintenance dosage is established．As a general guide，approximately 30-50 mg is a satisfactory initial dose，with 2 to 5 mg as a maintenance dose．The total dose may be administered once a day．It should be born in mind that the onset of therapeutic effect occurs only after about 30 hours．

Contraindications

In the presence of bleeding or a tendency to bleed(haemorrhage)，blood dyscrasias，purpura，open ulcerative，traumatic，or surgical wounds，ulcerations of the gastrointestinal tract，visceral carcinoma，diverticulitis，colitis，or subacute bacterial endocarditis，imminent abortion，recent surgery on the eye，brain or spinal cord，regional and lumbar block anaesthesia，vitamin K deficiency，severe hypertension，severe hepatic or renal disease，and when there iscontinuous tubal drainage of the gastrointestinal and urinary tracts．

Adverse reactions

Excessive doses may cause haematuria，bleeding from mucous membranes，haemorrhage from a wound or an ulcerative lesion or widespread petechial and purpuric haemorrhages．Paralytic ileus and intestinal obstruction have been reported from submucosal or intramural hemorrhage．Excessive uterine bleeding has occurred，but menstrual flow is usually normal．Bleeding following oral coumarin anticoagulant therapy does not always correlate with prothrombin activity．

In addition to haemorrhage and haemorrhagic manifestations，dermatitis，urticara，and alopecia have rarely been reported．Other less commonly reported side effects include fever and gastrointestinal symptoms varying from nausea and vomiting to abdominal cramping and diarrhoea．Haemorrhagic necrosis(bleeding into the skin and subcutaneous tissue with necrosis，vasculitis，and thrombosis)of the female breast and other areas has been reported in association with oral anticoagulant therapy．

Interactions

The concomitant use of salisylic acid or its derivatives may cause an increasing tendency to bleed．

Manufacturer

Orion Corporation，Orion Pharmaceutica，Espoo，Finland