英文药名: Purinethol (mercaptopurine tablets)
中文药名: 巯嘌呤片

药品名称
通用名称：巯嘌呤
英文名：Mercaptopurine
其它中文名：6-巯基嘌呤、6-巯嘌呤、巯唑嘌呤
其它英文名：Mercaptopurinum、Purinethol

规格
巯嘌呤片 50mg

药理作用　
药效学
属于抑制嘌呤合成途径的系胞同期特异性药物，化学结构与次黄嘌呤相似，因而能竞争性地抑制次黄嘌呤的转变过程，本品进入体内，在细胞内必须由磷酸核糖转移酶转为６-巯基嘌呤核糖核苷酸后才具有活性。其主要的作用环节有二：
①通过负反馈作用抑制酰胺转移酶，因而阻止1-焦磷酸-5-磷酸核糖(PRPP)转为1-氨基-5-磷酸核糖(PRA)的过程，干扰了嘌呤核苷酸合成的起始阶段；
②抑制复杂的嘌呤物间的相互转变，即能抑制次黄嘌呤核苷酸转为腺嘌呤核苷酸及次黄嘌呤核苷酸转为黄嘌呤核苷酸、鸟嘌呤核苷酸的过程，同时本品还抑制辅酶Ｉ(NAD+)的合成，并减少了生物合成DNA所必需的脱氧三磷酸腺苷(dATP)及脱氧三磷酸鸟苷(dGTP)，因而肿瘤细胞不能增殖，本品对处于 Ｓ增殖周期的细胞较敏感，除能抑制细胞 DNA的合成外，对细胞 RNA的合成亦有轻度的抑制作用。用巯嘌呤治疗白血病常产生耐药现象，其原因可能是体内出现了突变的白血病细胞株，因而失去了巯嘌呤转变巯嘌呤核糖核苷酸的能力。
药动学
口服后可迅速经胃肠道吸收。广泛分布于体液内，仅有较小量可渗入血脑屏障，因而一般口服的剂量，对预防和治疗脑膜白血病无效；血浆蛋白结合率约为 20％；本品吸收后的活化分解代谢过程主要在肝脏内进行，在肝内经黄嘌呤氧化酶等氧化及甲基化作用后分解为硫尿酸等产物而失去活性。静脉注射后的Ｔ1/2约为90分钟。约半量经代谢后在24小时即迅速从肾脏排出，其中7～39％以原形药排出，最慢的于开始服药后 17日才经肾脏排出。
适应症　　
适用于绒毛膜上皮癌、恶性葡萄胎、急性淋巴细胞白血病及急性非淋巴细胞白血病、慢性粒细胞白血病的急变期。

用法用量　　
1．成人常用量
(1)绒毛膜上皮癌。每日按体重 6— 6.5mg/kg，分 2次口服，以 10日为一疗程，疗程间歇为 3— 4周。
(2)白血病。
①开始，每日按体重 2.5mg/kg或按体表面积 80一100mg/平方米，每日 1次或分次服用，一般于用药后 2— 4周可见显效，如用药 4周后，仍未见临床改进及白细胞数下降，则可考虑在仔细观察下，加至按体重 5mg/kg；
②维持，每日按体重 1.5— 2.5mg/kg或按体表面积 50一 100mg/平方米。
2．小儿常用量：每日按体重 1.5— 2.5mg/kg或按体表面积 50mg/平方米，一次或分次口服。
任何疑问，请遵医嘱！

禁用/慎用　
(1)本品有增加胎儿死亡及先天性畸形的危险，故应避免在妊娠初期 3个月内服用本品。
(2)由于老年患者对化疗药物的耐受性较差，老年性白血病确须服用本品时，则需加强支持疗法，并严密观察症状、体征及周围血象等动态改变，及时调整剂量。
(3)下列情况应慎用：骨髓已有显著的抑制现象，血象表现有白细胞减少或血小板显著降低，并出现相应的严重感染或明显的出血现象者；有肝功能损害、肾功能损害、胆道疾患者；有痛风病史、尿酸盐肾结石病史者；4— 6周内已接受过细胞毒药物或放射治疗者。有肾或肝功能不全的患者，应适当地减少剂量。

给药说明　
(1)本品无论单用或联合应用时，均有抑制骨髓造血及免疫功能的反应，因而必须根据具体需要给予适当的支持疗法，例如新鲜血、血细胞成分、抗生素等。
(2)有肾或肝功能不全的患者，应适当地减少剂量。
(3)服用本品时，应适当增加患者液体的摄入量，并使尿液保持碱性，以阻止患者血清尿酸含量的增高及尿酸性肾病的发展。但加用别嘌醇时则应谨慎，仅限用于血尿酸含量显著增高的患者，如每日加服 300—600mg的别嘌醇时，巯嘌呤的剂量应减少至每日常用量的 1/3一1/4，这样既能减慢巯嘌呤的代谢，减少该药的毒性，又能阻止或减少高尿酸血症的产生。由于巯嘌呤会出现迟缓作用，因此在疗程中首次出现显著的粒细胞减少症、粒细胞缺乏症、血小板减少症，出血或出血倾向、黄疸等征象时，即应立即停药，当白细胞不再继续下降而保持稳定 2—3日或已上升时，再恢复给原来药物剂量的一半，继续服药。
(4)用药期间应注意定期检查周围血象及肝、肾功能。每周应随访白细胞计数及分类、血小板计数、血红蛋白量 1一2次，如血细胞在短期内有急骤下降现象者，应每日观察血象。

不良反应　
(1)较常见的为骨髓抑制，可有白细胞及血小板减少，常在服药后的第 5、6天出现，停药后仍可持续一周左右。
(2)肝脏损害：可致胆汁郁积出现黄疸。
(3)消化系统：恶心、呕吐、食欲减退，但较少发生，可见于服药量过大的患者。
(4)高尿酸血症：多见于白血病治疗初期，严重的可发生尿酸性肾病。
(5)口腔炎、腹泻、间质性肺炎及肺纤维化少见。
可引起胃肠道反应，恶心，呕吐，食欲不振，腹泻，口腔炎，口腔溃疡。骨髓抑制，白细胞及血小板减少，甚至全血象抑制。个别有肝损害，黄胆，高尿酸血症，结晶尿，肾损害。剂量过大有头晕，头痛，腹痛，皮疹。

药物相互作用　
(1)本品与别嘌醇同时服用时，由于后者抑制了巯嘌呤的代谢，明显地增加巯嘌呤的效能与毒性，因此在两药同时服用过程应仔细观察药物的不良反应，并适当地减少巯嘌呤的剂量。
(2)本品与对肝细胞有毒性的药物同服时，有增加本品对肝细胞毒害的危险，因而需权衡两药合用的利弊及必要性。
(3)本品与其他对骨髓有抑制的抗肿瘤药物或放射治疗合并应用时，会增强巯嘌呤的效应，因而须考虑调节本品的剂量与疗程。

【-原产地英文商品名-】MERCAPTOPURINE(PURINETHOL GENERIC) 50mg/tab 25tabs/box
【-原产地英文药品名-】MERCAPTOPURINE
【-中文参考药品译名-】巯嘌呤
【-中文参考商品译名-】
·巯嘌呤(PURINETHOL仿制药) 50毫克/片 25片/盒
·巯嘌呤(PURINETHOL仿制药) 50毫克/片 60片/盒
·巯嘌呤(PURINETHOL仿制药) 50毫克/片 100片/盒
·PURINETHOL 50毫克/片 60片/盒

Purinethol
Generic Name: mercaptopurine (Oral route)

mer-kap-toe-PURE-een

Commonly used brand name(s):
In the U.S.
Purinethol
Available Dosage Forms:
Tablet
Therapeutic Class: Antineoplastic Agent
Pharmacologic Class: Antimetabolite

-------------------------------------------------------------------------

Uses For Purinethol
Mercaptopurine belongs to the group of medicines known as antimetabolites. It is used to treat some kinds of cancer.

Mercaptopurine interferes with the growth of cancer cells, which are eventually destroyed. Since the growth of normal body cells may also be affected by mercaptopurine, other effects will also occur. Some of these may be serious and must be reported to your doctor. Other effects may not be serious but may cause concern. Some effects may not occur for months or years after the medicine is used.

Before you begin treatment with mercaptopurine, you and your doctor should talk about the good this medicine will do as well as the risks of using it.

Mercaptopurine may also be used for other conditions as determined by your doctor.

Mercaptopurine is available only with your doctor's prescription.

-------------------------------------------------------------------------

Before Using Purinethol
In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:

Allergies
Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.

Pediatric
Although there is no specific information comparing use of mercaptopurine in children with use in other age groups, it is not expected to cause different side effects or problems in children than it does in adults.

Geriatric
Many medicines have not been studied specifically in older people. Therefore, it may not be known whether they work exactly the same way they do in younger adults or if they cause different side effects or problems in older people. There is no specific information comparing use of mercaptopurine in the elderly with use in other age groups.

Breast Feeding
There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.

Interactions with Medicines
Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.

Febuxostat
Rotavirus Vaccine, Live

Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

Allopurinol
Azathioprine
Bacillus of Calmette and Guerin Vaccine, Live
Influenza Virus Vaccine, Live
Measles Virus Vaccine, Live
Mumps Virus Vaccine, Live
Poliovirus Vaccine, Live
Rotavirus Vaccine, Live
Rubella Virus Vaccine, Live
Smallpox Vaccine
Typhoid Vaccine
Varicella Virus Vaccine
Yellow Fever Vaccine

Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

Acenocoumarol
Methotrexate
Olsalazine
Warfarin

Interactions with Food/Tobacco/Alcohol
Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.

Other Medical Problems
The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:
Chickenpox (including recent exposure) or
Herpes zoster (shingles)—Risk of severe disease affecting other parts of the body
Gout (history of) or
Kidney stones (history of)—Mercaptopurine may increase levels of uric acid in the body, which can cause gout or kidney stones
Infection—Mercaptopurine may decrease your body's ability to fight infection
Kidney disease or
Liver disease—Effects of mercaptopurine may be increased because of slower removal from the body

-------------------------------------------------------------------------

Proper Use of Purinethol
Use this medicine only as directed by your doctor. Do not use more or less of it, and do not use it more often than your doctor ordered. The exact amount of medicine you need has been carefully worked out. Taking too much may increase the chance of side effects, while taking too little may not improve your condition.

Mercaptopurine is often given together with certain other medicines. If you are using a combination of medicines, make sure that you take each one at the right time and do not mix them. Ask your health care professional to help you plan a way to remember to take your medicines at the right times.

While you are using mercaptopurine, your doctor may want you to drink extra fluids so that you will pass more urine. This will help prevent kidney problems and keep your kidneys working well.

If you vomit shortly after taking a dose of mercaptopurine, check with your doctor. You will be told whether to take the dose again or to wait until the next scheduled dose.

Dosing
The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

Missed Dose
If you miss a dose of this medicine, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

Call your doctor or pharmacist for instructions.

Storage
Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.

Keep out of the reach of children.

Do not keep outdated medicine or medicine no longer needed.

-------------------------------------------------------------------------

Precautions While Using Purinethol
It is very important that your doctor check your progress at regular visits to make sure that this medicine is working properly and to check for unwanted effects.

Avoid alcoholic beverages until you have discussed their use with your doctor. Alcohol may increase the harmful effects of this medicine.

While you are being treated with mercaptopurine, and after you stop treatment with it, do not have any immunizations (vaccinations) without your doctor's approval. Mercaptopurine may lower your body's resistance and there is a chance you might get the infection the immunization is meant to prevent. In addition, other persons living in your household should not take oral polio vaccine since there is a chance they could pass the polio virus on to you. Also, avoid persons who have taken oral polio vaccine. Do not get close to them and do not stay in the same room with them for very long. If you cannot take these precautions, you should consider wearing a protective face mask that covers the nose and mouth.

Mercaptopurine can temporarily lower the number of white blood cells in your blood, increasing the chance of getting an infection. It can also lower the number of platelets, which are necessary for proper blood clotting. If this occurs, there are certain precautions you can take, especially when your blood count is low, to reduce the risk of infection or bleeding:
If you can, avoid people with infections. Check with your doctor immediately if you think you are getting an infection or if you get a fever or chills, cough or hoarseness, lower back or side pain, or painful or difficult urination.
Check with your doctor immediately if you notice any unusual bleeding or bruising; black, tarry stools; blood in urine or stools; or pinpoint red spots on your skin.
Be careful when using a regular toothbrush, dental floss, or toothpick. Your medical doctor, dentist, or nurse may recommend other ways to clean your teeth and gums. Check with your medical doctor before having any dental work done.
Do not touch your eyes or the inside of your nose unless you have just washed your hands and have not touched anything else in the meantime.
Be careful not to cut yourself when you are using sharp objects such as a safety razor or fingernail or toenail cutters.
Avoid contact sports or other situations where bruising or injury could occur.

Tell the doctor in charge that you are taking this medicine before you have any medical tests. The results of tests for the amount of sugar or uric acid in the blood measured by a machine called a sequential multiple analyzer (SMA) may be affected by this medicine.

-------------------------------------------------------------------------

Purinethol Side Effects
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Also, because of the way cancer medicines act on the body, there is a chance that they might cause other unwanted effects that may not occur until months or years after the medicine is used. These delayed effects may include certain types of cancer. Discuss these possible effects with your doctor.

Check with your doctor immediately if any of the following side effects occur:
Less common
Black, tarry stools
blood in urine or stools
cough or hoarseness
fever or chills
lower back or side pain
painful or difficult urination
pinpoint red spots on skin
unusual bleeding or bruising

Check with your doctor as soon as possible if any of the following side effects occur:
More common
Unusual tiredness or weakness
yellow eyes or skin

Less common
Joint pain
loss of appetite
nausea and vomiting
swelling of feet or lower legs

Rare
Sores in mouth and on lips

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

Less common
Darkening of skin
diarrhea
headache
skin rash and itching
weakness

After you stop using this medicine, it may still produce some side effects that need attention. During this period of time, check with your doctor immediately if you notice the following side effects:
Black, tarry stools
blood in urine or stools
cough or hoarseness
fever or chills
lower back or side pain
painful or difficult urination
pinpoint red spots on skin
unusual bleeding or bruising
yellow eyes or skin

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

The information contained in the Thomson Reuters Micromedex products as delivered by Drugs.com is intended as an educational aid only. It is not intended as medical advice for individual conditions or treatment. It is not a substitute for a medical exam, nor does it replace the need for services provided by medical professionals. Talk to your doctor, nurse or pharmacist before taking any prescription or over the counter drugs (including any herbal medicines or supplements) or following any treatment or regimen. Only your doctor, nurse, or pharmacist can provide you with advice on what is safe and effective for you.

The use of the Thomson Reuters Healthcare products is at your sole risk. These products are provided "AS IS" and "as available" for use, without warranties of any kind, either express or implied. Thomson Reuters Healthcare and Drugs.com make no representation or warranty as to the accuracy, reliability, timeliness, usefulness or completeness of any of the information contained in the products. Additionally, THOMSON REUTERS HEALTHCARE MAKES NO REPRESENTATION OR WARRANTIES AS TO THE OPINIONS OR OTHER SERVICE OR DATA YOU MAY ACCESS, DOWNLOAD OR USE AS A RESULT OF USE OF THE THOMSON REUTERS HEALTHCARE PRODUCTS. ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE OR USE ARE HEREBY EXCLUDED. Thomson Reuters Healthcare does not assume any responsibility or risk for your use of the Thomson Reuters Healthcare products.