英文药名: Macrobid(nitrofurantoin monohydrate capsules)

中文药名: 呋喃妥因水合物片剂

品牌药生产厂家: Procter & Gamble

药品名称

通用名: 呋喃妥因片
英文名: NITROFURANTOIN
药品类别: 硝基呋喃类
药理毒理

本品为抗菌药。大肠埃希菌对本品多呈敏感，产气肠杆菌、阴沟肠杆菌、变形杆菌属、克雷伯菌属等肠杆菌科细菌的部分菌株对本品敏感，铜绿假单胞菌通常对本品耐药。本品对肠球菌属等革兰阳性菌具有抗菌作用。本品的抗菌活性不受脓液及组织分解产物的影响，在酸性尿液中的活性较强，抗菌作用机制为干扰细菌体内氧化还原酶系统，从而阻断其代谢过程。
药代动力学

本品微晶型在小肠内迅速而完全吸收，大结晶型的吸收较缓。与食物同服可增加两种结晶型的生物利用度。血清中药物浓度甚低，尿中的浓度较高。本品可透过胎盘和血-脑脊液屏障。血清蛋白结合率为60%。血消除半衰期(t1/2?)为 0.3～1小时。肾小球滤过为主要排泄途径，少量自肾小管分泌和重吸收。30%～40%迅速以原形经尿排出，大结晶型的排泄较慢。本品亦可经胆汁排泄，并经透析清除。
适应症

用于对其敏感的大肠埃希菌、肠球菌属、葡萄球菌属以及克雷伯菌属、肠杆菌属等细菌所致的急性单纯性下尿路感染，也可用于尿路感染的预防。
用法用量

口服
成人一次50～100mg，一日3～4次。单纯性下尿路感染用低剂量；1月以上小儿每日按体重5～7mg/kg，分4 次服。疗程至少1周，或用至尿培养转阴后至少3日。
对尿路感染反复发作予本品预防者，成人一日50～ 100mg，睡前服，儿童一日1mg/kg。
任何疑问，请遵医嘱！
不良反应

1.恶心、呕吐、纳差和腹泻等胃肠道反应较常见。
2.皮疹、药物热、粒细胞减少、肝炎等变态反应亦可发生，有葡萄糖-6-磷酸脱氢酶缺乏者尚可发生溶血性贫血。
3.头痛、头昏、嗜睡、肌痛、眼球震颤等神经系统不良反应偶可发生，多属可逆，严重者可发生周围神经炎，原有肾功能减退或长期服用本品的病人易于发生。
4.呋喃妥因偶可引起发热、咳嗽、胸痛、肺部浸润和嗜酸粒细胞增多等急性肺炎表现，停药后可迅速消失，重症患者采用皮质激素可能减轻症状；长期服用6月以上的患者，偶可引起间质性肺炎或肺纤维化，应及早停药并采取相应治疗措施。
禁忌症

新生儿、足月孕妇、肾功能减退及对呋喃类药物过敏患者禁用。
注意事项

1.呋喃妥因宜与食物同服，以减少胃肠道刺激。
2.疗程应至少7日，或继续用药至尿中细菌清除3日以上。
3.长期应用本品6月以上者，有发生弥漫性间质性肺炎或肺纤维化的可能，应严密观察，及早发现，及时停药。因此将本品作长期预防应用者需权衡利弊。
4.葡萄糖-6-磷酸脱氢酶缺乏症、周围神经病变、肺部疾病患者慎用。
5.对实验室检查指标的干扰：本品可干扰尿糖测定，因其尿中代谢产物可使硫酸铜试剂发生假阳性反应。
孕妇及哺乳期妇女用药

1.因呋喃妥因可透过胎盘屏障，而胎儿酶系尚未发育完全，故妊娠后期孕妇不宜应用，足月孕妇禁用，以避免胎儿发生溶血性贫血的可能。
2.少量呋喃妥因可进入乳汁，诱发乳儿溶血性贫血，尤其是葡萄糖-6-磷酸脱氢酶缺乏者，服用本品应停止哺乳。
儿童用药

1个月以内的新生儿禁用。
老年患者用药

老年患者应慎用，并宜根据肾功能调整给药剂量。
药物相互作用

1.可导致溶血的药物与呋喃妥因合用时，有增加溶血反应的可能。
2.与肝毒性药物合用有增加肝毒性反应的可能；与神经毒性药物合用，有增加神经毒性的可能。
3.丙磺舒和苯磺唑酮均可抑制呋喃妥因的肾小管分泌，导致后者的血药浓度增高和（或）血清半衰期延长，而尿浓度则见降低，疗效亦减弱，丙磺舒等的剂量应予调整。
药物过量

本品过量的主要表现为呕吐。本品过量无特效解毒药。需进一步诱导呕吐，并给予大量补液，以保证药物随尿液排泄。本品也可经透析清除。
Macrobid is a wide spectrum antibiotic. It inhibits construction of a bacterial cell wall, synthesis of a bacterial DNA and RNA, proteins, inhibits aerobic metabolism. This medication is used to treat bacterial infections of the urinary tract caused by E. Coli, Enterobacter cystitis, Staphylococcus aureus, and Enterococcus, Klebsiella such as pyelitis, pyelonephritis, cystitis, urethritis, to prevent infections during urological surgeries, cystoscopy, catheterization. Macrobid is a sustained release macrocrystalline form of the antibiotic. Nitrofuranton is also available in a microcrystalline form (Furadantin), and a macrocrystalline form (Macrodantin). Absorption of the medication depends on the size of crystals and presence of food in the gastrointestinal tract.

Dosage and directions
Take 100 mg of Macrobid every 12 hours. Taking with a meal or milk increase its absorption and helps to avoid your stomach upset. Usual course of treatment continues seven days. Follow all recommendations of your doctor. Do not stop or start this medication without your doctor's permission.

Precautions
Before to take Macrobid inform your doctor if you have kidney disease, anemia, diabetes, an electrolyte imbalance, glucose-6-phosphate dehydrogenase (G6PD) deficiency, vitamin B deficiency, any type of debilitating disease. This medication can change results of urine glucose tests. This medication may cause diarrhea, if you have watery or bloody stools inform your doctor about. Do not take any antidiarrhea medication unless it was administered to you as diarrhea may be a sign of a new infection.

Contraindications
Macrobid cannot be used in patients with kidney or liver failure, jaundice in history, glucose-6-phosphate dehydrogenase deficiency, acute porphyria, pregnancy, in children under 12 years of age. Breastfeeding should be interrupted when on Macrobid.

Possible side effect
The most common adverse reactions are headache, dizziness, drowsiness, allergic reactions (rash, itching), nausea, vomiting. In rare cases diarrhea, loss of appetite, pseudomembranous colitis, and abdominal pain may occur.

Drug interaction
High doses of probenecid (Benemid) or sulfinpyrazone (Anturane) can inhibit secretion by kidney channels and decrease urine levels of Macrobid. Consequently blood concentrations of Macrobid increases as well as the risk of toxicity. Antibacteral effect of Macrobid is reduced by nalidixic acid, while is absorption is decreased by antacids which contain magnesium trisilicate. Co-administration with quinolone antibiotics such as norfloxacin (Noroxin) reduces their effects.

Missed dose
If you miss a dose, take it as soon as you remember unless it is almost time of your next dose. If it is near the time of the next dose, skip the missed dose and return dosing schedule. Do not double the dose to make up the missed dose.

Overdose
Symptoms of overdose include nausea or vomiting. If you suppose that too much of Macrobid was taken seek immediate medical attention.

Storage
Store at room temperature in a tight container, away from moisture and humidity.