英文药名: Macrobid(nitrofurantoin monohydrate capsules) 中文药名: 呋喃妥因水合物胶囊和片剂 生产厂家: Procter & Gamble 药品名称 通用名: 呋喃妥因 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。 【原产地英文商品名】MACROBID 100mg/cap 100caps/box 【原产地英文药品名】NITROFURANTOIN/NITROFURANTOIN MACROCRYSTAL 【原产地英文化合物名称】1-(5-Nitrofurfurylideneamino)hydantoin 【中文参考商品译名】 注：以下是不同的规格和不同的价格，购买时请以电话咨询为准！ ·MACROBID 100毫克/胶囊 30胶囊/盒 ·MACROBID 100毫克/胶囊 100胶囊/盒 ·MACROBID 100毫克/胶囊 20胶囊/盒 【中文参考药品译名】呋喃妥因/呋喃妥因晶体 【生产厂家中文参考译名】ALVOGEN 【生产厂家英文名】ALVOGEN Nitrofurantoin Macrocrystals Dosage Form: capsule Nitrofurantoin (Monohydrate/Macrocrystals) Capsules (Twice-a-day Dosage) To reduce the development of drug-resistant bacteria and maintain the effectiveness of nitrofurantoin monohydrate/macrocrystals capsules  and other antibacterial drugs, nitrofurantoin monohydrate/macrocrystals capsules  should be used only to treat or prevent infections that are proven or strongly suspected to be caused by bacteria. Nitrofurantoin Macrocrystals Description Nitrofurantoin is an antibacterial agent specific for urinary tract infections. Nitrofurantoin monohydrate/macrocrystals is a hard gelatin capsule shell containing the equivalent of 100 mg of nitrofurantoin in the form of 25 mg of Nitrofurantoin Macrocrystals and 75 mg of nitrofurantoin monohydrate. The chemical name of Nitrofurantoin Macrocrystals is 1-[[[5-nitro-2-furanyl]methylene]amino]-2,4-imidazolidinedione. The chemical structure is the following: Molecular Weight: 238.16 The chemical name of nitrofurantoin monohydrate is 1-[[[5-nitro-2-furanyl]methylene]amino]-2,4- imidazolidinedione monohydrate. The chemical structure is the following: Molecular Weight: 256.17 Inactive Ingredients Each capsule contains carbomer 934P, colloidal silicon dioxide, corn starch, compressible sugar, D&C yellow No. 10, edible white ink, FD&C blue No. 1, FD&C red No. 40, gelatin, lactose monohydrate, magnesium stearate, povidone, talc and titanium dioxide. Nitrofurantoin Macrocrystals - Clinical Pharmacology Each nitrofurantoin monohydrate/macrocrystals capsule contains two forms of nitrofurantoin. Twenty-five percent is macrocrystalline nitrofurantoin, which has slower dissolution and absorption than nitrofurantoin monohydrate. The remaining 75% is nitrofurantoin monohydrate contained in a powder blend which, upon exposure to gastric and intestinal fluids, forms a gel matrix that releases nitrofurantoin over time. Based on urinary pharmacokinetic data, the extent and rate of urinary excretion of nitrofurantoin from the 100 mg nitrofurantoin monohydrate/macrocrystals capsules  are similar to those of the 50 mg or 100 mg Nitrofurantoin Macrocrystals capsules. Approximately 20% to 25% of a single dose of nitrofurantoin is recovered from the urine unchanged over 24 hours. Plasma nitrofurantoin concentrations after a single oral dose of the 100 mg nitrofurantoin monohydrate/macrocrystals capsule are low, with peak levels usually less than 1 µg/mL. Nitrofurantoin is highly soluble in urine, to which it may impart a brown color. When nitrofurantoin monohydrate/macrocrystals capsules  are administered with food, the bioavailability of nitrofurantoin is increased by approximately 40%. Microbiology Nitrofurantoin is bactericidal in urine at therapeutic doses. The mechanism of the antimicrobial action of nitrofurantoin is unusual among antibacterials. Nitrofurantoin is reduced by bacterial flavoproteins to reactive intermediates which inactivate or alter bacterial ribosomal proteins and other macromolecules. As a result of such inactivations, the vital biochemical processes of protein synthesis, aerobic energy metabolism, DNA synthesis, RNA synthesis, and cell wall synthesis are inhibited. The broad-based nature of this mode of action may explain the lack of acquired bacterial resistance to nitrofurantoin, as the necessary multiple and simultaneous mutations of the target macromolecules would likely be lethal to the bacteria. Development of resistance to nitrofurantoin has not been a significant problem since its introduction in 1953. Cross-resistance with antibiotics and sulfonamides has not been observed, and transferable resistance is, at most, a very rare phenomenon. Nitrofurantoin, in the form of nitrofurantoin monohydrate/macrocrystals capsules, has been shown to be active against most strains of the following bacteria both in vitro and in clinical infections: (see INDICATIONS AND USAGE) Gram-Positive Aerobes Staphylococcus saprophyticus Gram-Negative Aerobes Escherichia coli Nitrofurantoin also demonstrates in vitro activity against the following microorganisms, although the clinical significance of these data with respect to treatment with nitrofurantoin monohydrate/macrocrystals capsules  is unknown: Gram-Positive Aerobes Coagulase-negative staphylococci (including Staphylococcus epidermidis) Enterococcus faecalis Staphylococcus aureus Streptococcus agalactiae Group D streptococci Viridans group streptococci Gram-Negative Aerobes Citrobacter amalonaticus Citrobacter diversus Citrobacter freundii Klebsiella oxytoca Klebsiella ozaenae Nitrofurantoin is not active against most strains of Proteus species or Serratia species. It has no activity against Pseudomonas species. Antagonism has been demonstrated in vitro between nitrofurantoin and quinolone antimicrobials. The clinical significance of this finding is unknown. Susceptibility Tests Dilution Techniques: Quantitative methods are used to determine antimicrobial minimal inhibitory concentrations (MIC’s). These MIC’s provide estimates of the susceptibility of bacteria to antimicrobial compounds. The MIC’s should be determined using a standardized procedure. Standardized procedures are based on a dilution method1 (broth or agar) or equivalent with standardized inoculum concentrations and standardized concentrations of nitrofurantoin powder. The MIC values should be interpreted according to the following criteria: MIC (µg/mL)Interpretation ≤32 Susceptible (S) 64 Intermediate (I) ≥128 Resistant (R) A report of "Susceptible" indicates that the pathogen is likely to be inhibited if the antimicrobial compound in the urine reaches the concentrations usually achievable. A report of "Intermediate" indicates that the result should be considered equivocal, and, if the microorganism is not fully susceptible to alternative, clinically feasible drugs, the test should be repeated. This category implies possible clinical applicability in body sites where the drug is physiologically concentrated or in situations where high dosage of drug can be used. This category also provides a buffer zone which prevents small uncontrolled technical factors from causing major discrepancies in interpretation. A report of "Resistant" indicates that the pathogen is not likely to be inhibited if the antimicrobial compound in the urine reaches the concentrations usually achievable; other therapy should be selected. Standardized susceptibility test procedures require the use of laboratory control microorganisms to control the technical aspects of the laboratory procedures. Standard nitrofurantoin powder should provide the following MIC values: MicroorganismMIC (µg/mL) E. coli ATCC 25922 4-16 S. aureus ATCC 29213 8-32 E. faecalis ATCC 29212 4-16 Diffusion Techniques: Quantitative methods that require measurement of zone diameters also provide reproducible estimates of the susceptibility of bacteria to antimicrobial compounds. One such standardized procedure2 requires the use of standardized inoculum concentrations. This procedure uses paper disks impregnated with 300 µg nitrofurantoin to test the susceptibility of microorganisms to nitrofurantoin. Reports from the laboratory providing results of the standard single-disk susceptibility test with a 300-µg nitrofurantoin disk should be interpreted according to the following criteria: Zone Diameter (mm)Interpretation ≥17 Susceptible (S) 15-16 Intermediate (I) ≤14 Resistant (R) Interpretation should be as stated above for results using dilution techniques. Interpretation involves correlation of the diameter obtained in the disk test with the MIC for nitrofurantoin. As with standardized dilution techniques, diffusion methods require the use of laboratory control microorganisms that are used to control the technical aspects of the laboratory procedures. For the diffusion technique, the 300 µg nitrofurantoin disk should provide the following zone diameters in these laboratory test quality control strains: MicroorganismZone Diameter (mm) E. coli ATCC 25922 20-25 S. aureus ATCC 25923 18-22 Indications and Usage for Nitrofurantoin Macrocrystals Nitrofurantoin monohydrate/macrocrystals capsules are indicated only for the treatment of acute uncomplicated urinary tract infections (acute cystitis) caused by susceptible strains of Escherichia coli or Staphylococcus saprophyticus. Nitrofurantoin is not indicated for the treatment of pyelonephritis or perinephric abscesses. To reduce the development of drug-resistant bacteria and maintain the effectiveness of nitrofurantoin monohydrate/macrocrystals capsules  and other antibacterial drugs, nitrofurantoin monohydrate/macrocrystals capsules  should be used only to treat or prevent infections that are proven or strongly suspected to be caused by susceptible bacteria. When culture and susceptibility information are available, they should be considered in selecting or modifying antibacterial therapy. In the absence of such data, local epidemiology and susceptibility patterns may contribute to the empiric selection of therapy. Nitrofurantoins lack the broader tissue distribution of other therapeutic agents approved for urinary tract infections. Consequently, many patients who are treated with nitrofurantoin monohydrate/macrocrystals capsules  are predisposed to persistence or reappearance of bacteriuria (see CLINICAL STUDIES). Urine specimens for culture and susceptibility testing should be obtained before and after completion of therapy. If persistence or reappearance of bacteriuria occurs after treatment with nitrofurantoin monohydrate/macrocrystals capsules, other therapeutic agents with broader tissue distribution should be selected. In considering the use of nitrofurantoin monohydrate/macrocrystals capsules, lower eradication rates should be balanced against the increased potential for systemic toxicity and for the development of antimicrobial resistance when agents with broader tissue distribution are utilized. Contraindications Anuria, oliguria, or significant impairment of renal function (creatinine clearance under 60 mL per minute or clinically significant elevated serum creatinine) are contraindications. Treatment of this type of patient carries an increased risk of toxicity because of impaired excretion of the drug. Because of the possibility of hemolytic anemia due to immature erythrocyte enzyme systems (glutathione instability), the drug is contraindicated in pregnant patients at term (38 to 42 weeks gestation), during labor and delivery, or when the onset of labor is imminent. For the same reason, the drug is contraindicated in neonates under one month of age. Nitrofurantoin monohydrate/macrocrystals  are also contraindicated in patients with a previous history of cholestatic jaundice/hepatic dysfunction associated with nitrogurantoin. Nitrofurantoin monohydrate/macrocrystals are also contraindicated in those patients with known hypersensitivity to nitrofurantoin. Warnings ACUTE, SUBACUTE, OR CHRONIC PULMONARY REACTIONS HAVE BEEN OBSERVED IN PATIENTS TREATED WITH NITROFURANTOIN. IF THESE REACTIONS OCCUR, NITROFURANTOIN MONOHYDRATE/ MACROCRYSTALS SHOULD BE DISCONTINUED AND APPROPRIATE MEASURES TAKEN. REPORTS HAVE CITED PULMONARY REACTIONS AS A CONTRIBUTING CAUSE OF DEATH. CHRONIC PULMONARY REACTIONS (DIFFUSE INTERSTITIAL PNEUMONITIS OR PULMONARY FIBROSIS, OR BOTH) CAN DEVELOP INSIDIOUSLY. THESE REACTIONS OCCUR RARELY AND GENERALLY IN PATIENTS RECEIVING THERAPY FOR SIX MONTHS OR LONGER. CLOSE MONITORING OF THE PULMONARY CONDITION OF PATIENTS RECEIVING LONG-TERM THERAPY IS WARRANTED AND REQUIRES THAT THE BENEFITS OF THERAPY BE WEIGHED AGAINST POTENTIAL RISKS. (SEE RESPIRATORY REACTIONS.) Hepatotoxicity Hepatic reactions, including hepatitis, cholestatic jaundice, chronic active hepatitis, and hepatic necrosis, occur rarely. Fatalities have been reported. The onset of chronic active hepatitis may be insidious, and patients should be monitored periodically for changes in biochemical tests that would indicate liver injury. If hepatitis occurs, the drug should be withdrawn immediately and appropriate measures should be taken. Neuropathy Peripheral neuropathy, which may become severe or irreversible, has occurred. Fatalities have been reported. Conditions such as renal impairment (creatinine clearance under 60 mL per minute or clinically significant elevated serum creatinine), anemia, diabetes mellitus, electrolyte imbalance, vitamin B deficiency, and debilitating disease may enhance the occurrence of peripheral neuropathy. Patients receiving long-term therapy should be monitored periodically for changes in renal function. Optic neuritis has been reported rarely in postmarketing experience with nitrofurantoin formulations. Nemolytic Anemia Cases of hemolytic anemia of the primaquine-sensitivity type have been induced by nitrofurantoin. Hemolysis appears to be linked to a glucose-6-phosphate dehydrogenase deficiency in the red blood cells of the affected patients. This deficiency is found in 10 percent of Blacks and a small percentage of ethnic groups of Mediterranean and Near-Eastern origin. Hemolysis is an indication for discontinuing nitrofurantoin monohydrate/macrocrystals capsules; hemolysis ceases when the drug is withdrawn. Clostridium difficile-Associated Diarrhea Clostridium difficile associated diarrhea (CDAD) has been reported with use of nearly all antibacterial agents, including nitrofurantoin, and may range in severity from mild diarrhea to fatal colitis. Treatment with antibacterial agents alters the normal flora of the colon leading to overgrowth of C. difficile. C. difficile produces toxins A and B which contribute to the development of CDAD. Hypertoxin producing strains of C. difficile cause increased morbidity and mortality, as these infections can be refractory to antimicrobial therapy and may require colectomy. CDAD must be considered in all patients who present with diarrhea following antibiotic use. Careful medical history is necessary since CDAD has been reported to occur over two months after the administration of antibacterial agents. If CDAD is suspected or confirmed, ongoing antibiotic use not directed against C. difficile may need to be discontinued. Appropriate fluid and electrolyte management, protein supplementation, antibiotic treatment of C. difficile, and surgical evaluation should be instituted as clinically indicated. Precautions Information for Patients Patients should be advised to take nitrofurantoin monohydrate/macrocrystals with food (ideally breakfast and dinner) to further enhance tolerance and improve drug absorption. Patients should be instructed to complete the full course of therapy; however, they should be advised to contact their physician if any unusual symptoms occur during therapy. Patients should be advised not to use antacid preparations containing magnesium trisilicate while taking nitrofurantoin monohydrate/macrocrystals. Patients should be counseled that antibacterial drugs including nitrofurantoin monohydrate/macrocrystals  should only be used to treat bacterial infections. They do not treat viral infections (e.g., the common cold). When nitrofurantoin monohydrate/macrocrystals  are prescribed to treat a bacterial infection, patients should be told that although it is common to feel better early in the course of therapy, the medication should be taken exactly as directed. Skipping doses or not completing the full course of therapy may (1) decrease the effectiveness of the immediate treatment and (2) increase the likelihood that bacteria will develop resistance and will not be treatable by nitrofurantoin monohydrate/macrocrystals  or other antibacterial drugs in the future. Diarrhea is a common problem caused by antibiotics which usually ends when the antibiotic is discontinued. Sometimes after starting treatment with antibiotics, patients can develop watery and bloody stools (with or without stomach cramps and fever) even as late as two or more months after having taken the last dose of the antibiotic. If this occurs, patients should contact their physician as soon as possible. General Prescribing nitrofurantoin monohydrate/macrocrystals  in the absence of a proven or strongly suspected bacterial infection or a prophylactic indication is unlikely to provide benefit to the patient and increases the risk of the development of drug-resistant bacteria. Interactions Drug Interactions Antacids containing magnesium trisilicate, when administered concomitantly with nitrofurantoin, reduce both the rate and extent of absorption. The mechanism for this interaction probably is adsorption of nitrofurantoin onto the surface of magnesium trisilicate. Uricosuric drugs, such as probenecid and sulfinpyrazone, can inhibit renal tubular secretion of nitrofurantoin. The resulting increase in nitrofurantoin serum levels may increase toxicity, and the decreased urinary levels could lessen its efficacy as a urinary tract antibacterial. Drug/Laboratory Test Interactions As a result of the presence of nitrofurantoin, a false-positive reaction for glucose in the urine may occur. This has been observed with Benedict’s and Fehling’s solutions but not with the glucose enzymatic test. Carcinogenesis, Mutagenesis, Impairment of Fertility Nitrofurantoin was not carcinogenic when fed to female Holtzman rats for 44.5 weeks or to female Sprague-Dawley rats for 75 weeks. Two chronic rodent bioassays utilizing male and female Sprague-Dawley rats and two chronic bioassays in Swiss mice and in BDF1 mice revealed no evidence of carcinogenicity. Nitrofurantoin presented evidence of carcinogenic activity in female B6C3F1 mice as shown by increased incidences of tubular adenomas, benign mixed tumors, and granulosa cell tumors of the ovary. In male F344/N rats, there were increased incidences of uncommon kidney tubular cell neoplasms, osteosarcomas of the bone, and neoplasms of the subcutaneous tissue. In one study involving subcutaneous administration of 75 mg/kg nitrofurantoin to pregnant female mice, lung papillary adenomas of unknown significance were observed in the F1 generation. Nitrofurantoin has been shown to induce point mutations in certain strains of Salmonella typhimurium and forward mutations in L5178Y mouse lymphoma cells. Nitrofurantoin induced increased numbers of sister chromatid exchanges and chromosomal aberrations in Chinese hamster ovary cells but not in human cells in culture. Results of the sex-linked recessive lethal assay in Drosophila were negative after administration of nitrofurantoin by feeding or by injection. Nitrofurantoin did not induce heritable mutation in the rodent models examined. The significance of the carcinogenicity and mutagenicity findings relative to the therapeutic use of nitrofurantoin in humans is unknown. The administration of high doses of nitrofurantoin to rats causes temporary spermatogenic arrest; this is reversible on discontinuing the drug. Doses of 10 mg/kg/day or greater in healthy human males may, in certain unpredictable instances, produce a slight to moderate spermatogenic arrest with a decrease in sperm count. Pregnancy Teratogenic Effects  Pregnancy Category B  Several reproduction studies have been performed in rabbits and rats at doses up to six times the human dose and have revealed no evidence of impaired fertility or harm to the fetus due to nitrofurantoin. In a single published study conducted in mice at 68 times the human dose (based on mg/kg administered to the dam), growth retardation and a low incidence of minor and common malformations were observed. However, at 25 times the human dose, fetal malformations were not observed; the relevance of these findings to humans is uncertain. There are, however, no adequate and well-controlled studies in pregnant women. Because animal reproduction studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed. Non-teratogenic Effects  Nitrofurantoin has been shown in one published transplacental carcinogenicity study to induce lung papillary adenomas in the F1 generation mice at doses 19 times the human dose on a mg/kg basis. The relationship of this finding to potential human carcinogenesis is presently unknown. Because of the uncertainty regarding the human implications of these animal data, this drug should be used during pregnancy only if clearly needed. Labor and Delivery See CONTRAINDICATIONS. Nursing Mothers Nitrofurantoin has been detected in human breast milk in trace amounts. Because of the potential for serious adverse reactions from nitrofurantoin in nursing infants under one month of age, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother (see CONTRAINDICATIONS). Pediatric Use Nitrofurantoin monohydrate/macrocrystals  are contraindicated in infants below the age of one month (see CONTRAINDICATIONS). Safety and effectiveness in pediatric patients below the age of twelve years have not been established. Geriatric Use Clinical studies of nitrofurantoin monohydrate/macrocrystals  did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger patients. Spontaneous reports suggest a higher proportion of pulmonary reactions, including fatalities, in elderly patients; these differences appear to be related to the higher proportion of elderly patients receiving long-term nitrofurantoin therapy. As in younger patients, chronic pulmonary reactions generally are observed in patients receiving therapy for six months or longer (see WARNINGS). Spontaneous reports also suggest an increased proportion of severe hepatic reactions, including fatalities, in elderly patients (see WARNINGS). In general, the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy in elderly patients should be considered when prescribing nitrofurantoin monohydrate/macrocrystals. This drug is known to be substantially excreted by the kidney, and the risk of toxic reactions to this drug may be greater in patients with impaired renal function. Anuria, oliguria, or significant impairment of renal function (creatinine clearance under 60 mL per minute or clinically significant elevated serum creatinine) are contraindications (see CONTRAINDICATIONS). Because elderly patients are more likely to have decreased renal function, it may be useful to monitor renal function. Adverse Reactions In clinical trials of nitrofurantoin monohydrate/macrocrystals, the most frequent clinical adverse events that were reported as possibly or probably drug-related were nausea (8%), headache (6%), and flatulence (1.5%). Additional clinical adverse events reported as possibly or probably drug-related occurred in less than 1% of patients studied and are listed below within each body system in order of decreasing frequency: Gastrointestinal: Diarrhea, dyspepsia, abdominal pain, constipation, emesis Neurologic: Dizziness, drowsiness, amblyopia Respiratory: Acute pulmonary hypersensitivity reaction (see WARNINGS) Allergic: Pruritus, urticaria Dermatologic: Alopecia Miscellaneous: Fever, chills, malaise The following additional clinical adverse events have been reported with the use of nitrofurantoin: Gastrointestinal: Sialadenitis, pancreatitis. There have been sporadic reports of pseudomembranous colitis with the use of nitrofurantoin. The onset of pseudomembranous colitis symptoms may occur during or after antimicrobial treatment (see WARNINGS). Neurologic: Peripheral neuropathy, which may become severe or irreversible, has occurred. Fatalities have been reported. Conditions such as renal impairment (creatinine clearance under 60 mL per minute or clinically significant elevated serum creatinine), anemia, diabetes mellitus, electrolyte imbalance, vitamin B deficiency, and debilitating diseases may increase the possibility of peripheral neuropathy (see WARNINGS). Asthenia, vertigo, and nystagmus also have been reported with the use of nitrofurantoin. Benign intracranial hypertension (pseudotumor cerebri), confusion, depression, optic neuritis, and psychotic reactions have been reported rarely. Bulging fontanels, as a sign of benign intracranial hypertension in infants, have been reported rarely. Respiratory: CHRONIC, SUBACUTE, OR ACUTE PULMONARY HYPERSENSITIVITY REACTIONS MAY OCCUR WITH THE USE OF NITROFURANTOIN. CHRONIC PULMONARY REACTIONS GENERALLY OCCUR IN PATIENTS WHO HAVE RECEIVED CONTINUOUS TREATMENT FOR SIX MONTHS OR LONGER. MALAISE, DYSPNEA ON EXERTION, COUGH, AND ALTERED PULMONARY FUNCTION ARE COMMON MANIFESTATIONS WHICH CAN OCCUR INSIDIOUSLY. RADIOLOGIC AND HISTOLOGIC FINDINGS OF DIFFUSE INTERSTITIAL PNEUMONITIS OR FIBROSIS, OR BOTH, ARE ALSO COMMON MANIFESTATIONS OF THE CHRONIC PULMONARY REACTION. FEVER IS RARELY PROMINENT. THE SEVERITY OF CHRONIC PULMONARY REACTIONS AND THEIR DEGREE OF RESOLUTION APPEAR TO BE RELATED TO THE DURATION OF THERAPY AFTER THE FIRST CLINICAL SIGNS APPEAR. PULMONARY FUNCTION MAY BE IMPAIRED PERMANENTLY, EVEN AFTER CESSATION OF THERAPY. THE RISK IS GREATER WHEN CHRONIC PULMONARY REACTIONS ARE NOT RECOGNIZED EARLY. In subacute pulmonary reactions, fever and eosinophilia occur less often than in the acute form. Upon cessation of therapy, recovery may require several months. If the symptoms are not recognized as being drug-related and nitrofurantoin therapy is not stopped, the symptoms may become more severe. Acute pulmonary reactions are commonly manifested by fever, chills, cough, chest pain, dyspnea, pulmonary infiltration with consolidation or pleural effusion on x-ray, and eosinophilia. Acute reactions usually occur within the first week of treatment and are reversible with cessation of therapy. Resolution often is dramatic (see WARNINGS). Changes in EKG (e.g., non-specific ST/T wave changes, bundle branch block) have been reported in association with pulmonary reactions. Cyanosis has been reported rarely. Hepatic: Hepatic reactions, including hepatitis, cholestatic jaundice, chronic active hepatitis, and hepatic necrosis, occur rarely (see WARNINGS). Allergic: Lupus-like syndrome associated with pulmonary reaction to nitrofurantoin has been reported. Also, angioedema; maculopapular, erythematous, or eczematous eruptions; anaphylaxis; arthralgia; myalgia; drug fever; and chills have been reported. Hypersensitivity reactions represent the most frequent spontaneously-reported adverse events in worldwide postmarketing experience with nitrofurantoin formulations. Dermatologic: Exfoliative dermatitis and erythema multiforme (including Stevens-Johnson syndrome) have been reported rarely. Hematologic: Cyanosis secondary to methemoglobinemia has been reported rarely. Miscellaneous: As with other antimicrobial agents, superinfections caused by resistant organisms, e.g., Pseudomonas species or Candida species, can occur. In clinical trials of nitrofurantoin monohydrate/macrocrystals, the most frequent laboratory adverse events (1% to 5%), without regard to drug relationship, were as follows: eosinophilia, increased AST (SGOT), increased ALT (SGPT), decreased hemoglobin, increased serum phosphorus. The following laboratory adverse events also have been reported with the use of nitrofurantoin: glucose-6-phosphate dehydrogenase deficiency anemia (see WARNINGS), agranulocytosis, leukopenia, granulocytopenia, hemolytic anemia, thrombocytopenia, megaloblastic anemia. In most cases, these hematologic abnormalities resolved following cessation of therapy. Aplastic anemia has been reported rarely. Overdosage Occasional incidents of acute overdosage of nitrofurantoin have not resulted in any specific symptoms other than vomiting. Induction of emesis is recommended. There is no specific antidote, but a high fluid intake should be maintained to promote urinary excretion of the drug. Nitrofurantoin is dialyzable. Nitrofurantoin Macrocrystals Dosage and Administration Nitrofurantoin monohydrate/macrocrystals capsules  should be taken with food. Adults and Pediatric Patients Over 12 Years One 100 mg capsule every 12 hours for seven days. How is Nitrofurantoin Macrocrystals Supplied Nitrofurantoin monohydrate/macrocrystals capsules, for oral administration, are available as: 100 mg: Black and ivory opaque capsules imprinted “E 122” on the cap and body and supplied as: NDC 0185-0122-01 bottles of 100 NDC 0185-0122-10 bottles of 1,000 Store at 20° to 25°C (68° to 77°F) [see USP Controlled Room Temperature].