英文药名: Rapaflo(Silodosin caps) 中文药名: 西洛多辛胶囊 生产厂家: Allergan 药品简介 FDA于2008年10月4日批准Watson公司的silodosin胶囊 (Rapaflo) 用于改善良性前列腺增生（也称为前列腺肥大）（BHP）引起的症状。良性前列腺增生在50岁男性中的发病率为50%，在80年男性中的发病率升高至 75%。本品通过阻断前列腺、膀胱、输尿管中的肾上腺α1受体而起作用，通过阻断这些受体，使得在这些组织中的平滑肌得以放松，从而减轻前列腺增生的症状。 本品为一日1次的胶囊剂，针对无肝肾功能损伤患者的服用剂量为8mg/天，轻中度肝肾功能损伤患者的服用剂量是4mg/天，本品不推荐在重度肝肾功能损伤的患者中使用。两项纳入923例患者为期12周的随机双盲安慰剂对照的多中心临床研究结果表明：本品与安慰剂相比对BHP症状的改善情况与小便通畅率的改善均有显著的统计学意义。 本品的主要不良反应为在性高潮期间没有精液排除或者精液排除减少。但这一不良反应不会纳入对本品的安全性考虑，其他的不良反应还包括眩晕，头昏，腹泻，体位性高血压，头痛，鼻咽炎，鼻充血等。 RAPAFLO CAP 8MG 30  SILODOSIN  ALLERGAN PHARMACEUTICAL  52544-0152-30    RAPAFLO CAP 8MG 90  SILODOSIN  ALLERGAN PHARMACEUTICAL  52544-0152-19             RAPAFLO CAP 4MG 30  SILODOSIN  ALLERGAN PHARMACEUTICAL  52544-0151-30 RAPAFLO(Silodosin) 1. DESCRIPTION Silodosin is a selective antagonist of alpha-1 adrenoreceptors. The chemical name of silodosin is 1-(3-Hydroxypropyl)-5-[(2R)-2-({2-[2-(2,2,2-trifluoroethoxy) phenoxy]ethyl}amino)propyl]-2,3-dihydro-1H-indole-7-carboxamide and the molecular formula is C25H32F3N3O4 with a molecular weight of 495.53. The structural formula of silodosin is: Silodosin is a white to pale yellowish white powder that melts at approximately 105 to 109°C. It is very soluble in acetic acid, freely soluble in alcohol, and very slightly soluble in water. Each silodosin 8 mg capsule for oral administration contains 8 mg silodosin, and the following inactive ingredients: D-mannitol, magnesium stearate, pregelatinized starch, and sodium lauryl sulfate. The size #1 hard gelatin capsules contain gelatin and titanium dioxide. The capsules are printed with edible ink containing FD&C Blue No. 1 Aluminum Lake and yellow iron oxide. Each silodosin 4 mg capsule for oral administration contains 4 mg silodosin, and the following inactive ingredients: D-mannitol, magnesium stearate, pregelatinized starch, and sodium lauryl sulfate. The size #3 hard gelatin capsules contain gelatin and titanium dioxide. The capsules are printed with edible ink containing yellow iron oxide. 2. INDICATIONS AND USAGE Silodosin, a selective alpha-1 adrenergic receptor antagonist, is indicated for the treatment of the signs and symptoms of benign prostatic hyperplasia (BPH). Silodosin is not indicated for the treatment of hypertension. 3. DOSAGE AND ADMINISTRATION 3.1 Dosing Information The recommended dose is 8 mg orally once daily with a meal. Patients who have difficulty swallowing pills and capsules may carefully open the silodosin capsule and sprinkle the powder inside on a tablespoonful of applesauce. The applesauce should be swallowed immediately (within 5 minutes) without chewing and followed with an 8 oz glass of cool water to ensure complete swallowing of the powder. The applesauce used should not be hot, and it should be soft enough to be swallowed without chewing. Any powder/applesauce mixture should be used immediately (within 5 minutes) and not stored for future use. Subdividing the contents of a silodosin capsule is not recommended. 3.2 Dosage Adjustment in Special Populations Renal impairment: Silodosin is contraindicated in patients with severe renal impairment (CCr < 30 mL/min). In patients with moderate renal impairment (CCr 30-50 mL/min), the dose should be reduced to 4 mg once daily taken with a meal. No dosage adjustment is needed in patients with mild renal impairment (CCr 50-80 mL/min) [see Contraindications, Warnings and Precautions, Use in Specific Populations]. Hepatic impairment: Silodosin has not been studied in patients with severe hepatic impairment (Child-Pugh score ≥ 10) and is therefore contraindicated in these patients. No dosage adjustment is needed in patients with mild or moderate hepatic impairment [see Contraindications, Warnings and Precautions, Use in Specific Populations]. 4. CONTRAINDICATIONS • Severe renal impairment (CCr < 30 mL/min) • Severe hepatic impairment (Child-Pugh score ≥ 10) • Concomitant administration with strong Cytochrome P450 3A4 (CYP3A4) inhibitors (e.g., ketoconazole, clarithromycin, itraconazole, ritonavir) [see Drug Interactions]. 5. MECHANISM OF ACTION Silodosin is a selective antagonist of post-synaptic alpha-1 adrenoreceptors, which are located in the human prostate, bladder base, bladder neck, prostatic capsule, and prostatic urethra. Blockade of these alpha-1 adrenoreceptors can cause smooth muscle in these tissues to relax, resulting in an improvement in urine flow and a reduction in BPH symptoms. An in vitro study examining binding affinity of silodosin to the three subtypes of the alpha-1 adrenoreceptors (alpha-1A, alpha-1B, and alpha-1D) was conducted. The results of the study demonstrated that silodosin binds with high affinity to the alpha-1A subtype. 6. USE IN SPECIFIC POPULATIONS 6.1 Usage in Pregnancy Pregnancy Category B Silodosin is not indicated for use in women. An embryo/fetal study in rabbits showed decreased maternal body weight at 200 mg/kg/day (approximately 13-25 times the maximum recommended human exposure or MRHE of silodosin via AUC). No statistically significant teratogenicity was observed at this dose. Silodosin was not teratogenic when administered to pregnant rats during organogenesis at 1000 mg/kg/day (estimated to be approximately 20 times the MRHE). No maternal or fetal effects were observed at this dose. Rats and rabbits do not produce glucuronidated silodosin, which is present in human serum at approximately 4 times the level of circulating silodosin and which has similar pharmacological activity to silodosin. No effects on physical or behavioral development of offspring were observed when rats were treated during pregnancy and lactation at up to 300 mg/kg/day. 6.2 Pediatric Use Silodosin is not indicated for use in pediatric patients. Safety and effectiveness in pediatric patients have not been established. 6.3 Geriatric Use In double-blind, placebo-controlled, 12-week clinical studies of silodosin, 259 (55.6%) were under 65 years of age, 207 (44.4%) patients were 65 years of age and over, while 60 (12.9%) patients were 75 years of age and over. Orthostatic hypotension was reported in 2.3% of silodosin patients < 65 years of age (1.2% for placebo), 2.9% of silodosin patients ≥ 65 years of age (1.9% for placebo), and 5.0% of patients ≥ 75 years of age (0% for placebo). There were otherwise no significant differences in safety or effectiveness between older and younger patients. 6.4 Renal Impairment The effect of renal impairment on silodosin pharmacokinetics was eva luated in a single dose study of six male patients with moderate renal impairment and seven male subjects with normal renal function. Plasma concentrations of silodosin were approximately three times higher in subjects with moderate renal impairment compared with subjects with normal renal function. Silodosin should be reduced to 4 mg per day in patients with moderate renal impairment. Exercise caution and monitor patients for adverse events. Silodosin has not been studied in patients with severe renal impairment. Silodosin is contraindicated in patients with severe renal impairment [see Contraindications, Warnings and Precautions]. 6.5 Hepatic Impairment In a study comparing nine male patients with moderate hepatic impairment (Child-Pugh scores 7 to 9), to nine healthy male subjects, the single dose pharmacokinetics of silodosin were not significantly altered in patients with hepatic impairment. No dosing adjustment is required in patients with mild or moderate hepatic impairment. Silodosin has not been studied in patients with severe hepatic impairment. Silodosin is contraindicated in patients with severe hepatic impairment [see Contraindications, Warnings and Precautions]. 7. WARNINGS AND PRECAUTIONS 7.1 Orthostatic Effects Postural hypotension, with or without symptoms (e.g., dizziness) may develop when beginning silodosin treatment. As with other alpha-blockers, there is potential for syncope. Patients should be cautioned about driving, operating machinery, or performing hazardous tasks when initiating therapy [see Adverse Reactions]. 7.2 Renal Impairment In a clinical pharmacology study, plasma concentrations (AUC and Cmax) of silodosin were approximately three times higher in subjects with moderate renal impairment compared with subjects with normal renal function, while half-lives of silodosin doubled in duration. The dose of silodosin should be reduced to 4 mg in patients with moderate renal impairment. Exercise caution and monitor such patients for adverse events [see Use in Specific Populations]. 7.3 Hepatic Impairment Silodosin has not been tested in patients with severe hepatic impairment, and therefore, should not be prescribed to such patients [see Contraindications, Use in Specific Populations]. 7.4 Pharmacokinetic Drug-Drug Interactions In a drug interaction study, co-administration of a single 8 mg dose of silodosin with 400 mg ketoconazole, a strong CYP3A4 inhibitor, caused a 3.8-fold increase in maximum plasma silodosin concentrations and 3.2-fold increase in silodosin exposure (i.e., AUC). Concomitant use of ketoconazole or other strong CYP3A4 inhibitors (e.g., itraconazole, clarithromycin, ritonavir) is therefore contraindicated [see Drug Interactions]. 7.5 Pharmacodynamic Drug-Drug Interactions The pharmacodynamic interactions between silodosin and other alpha-blockers have not been determined. However, interactions may be expected, and silodosin should not be used in combination with other alpha-blockers [see Drug Interactions]. A specific pharmacodynamic interaction study between silodosin and antihypertensive agents has not been performed. However, patients in the Phase 3 clinical studies taking concomitant antihypertensive medications with silodosin did not experience a significant increase in the incidence of syncope, dizziness, or orthostasis. Nevertheless, exercise caution during concomitant use with antihypertensives and monitor patients for possible adverse events [see Adverse Reactions and Drug Interactions]. 7.6 Carcinoma of the Prostate Carcinoma of the prostate and BPH cause many of the same symptoms. These two diseases frequently co-exist. Therefore, patients thought to have BPH should be examined prior to starting therapy with silodosin to rule out the presence of carcinoma of the prostate. 7.7 Intraoperative Floppy Iris Syndrome Intraoperative Floppy Iris Syndrome has been observed during cataract surgery in some patients on alpha-1 blockers or previously treated with alpha-1 blockers. This variant of small pupil syndrome is characterized by the combination of a flaccid iris that billows in response to intraoperative irrigation currents; progressive intraoperative miosis despite preoperative dilation with standard mydriatic drugs; and potential prolapse of the iris toward the phacoemulsification incisions. Patients planning cataract surgery should be told to inform their ophthalmologist that they are taking silodosin [see Adverse Reactions]. 7.8 Laboratory Test Interactions No laboratory test interactions were observed during clinical eva luations. Treatment with silodosin for up to 52 weeks had no significant effect on prostate-specific antigen (PSA). 8. ADVERSE REACTIONS 8.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice. In U.S. clinical trials, 897 patients with BPH were exposed to 8 mg silodosin daily. This includes 486 patients exposed for 6 months and 168 patients exposed for 1 year. The population was 44 to 87 years of age, and predominantly Caucasian. Of these patients, 42.8% were 65 years of age or older and 10.7% were 75 years of age or older. In double-blind, placebo controlled, 12-week clinical trials, 466 patients were administered silodosin and 457 patients were administered placebo. At least one treatment-emergent adverse reaction was reported by 55.2% of silodosin treated patients (36.8% for placebo treated). The majority (72.1%) of adverse reactions for the silodosin treated patients (59.8% for placebo treated) were qualified by the investigator as mild. A total of 6.4% of silodosin treated patients (2.2% for placebo treated) discontinued therapy due to an adverse reaction (treatment-emergent), the most common reaction being retrograde ejaculation (2.8%) for silodosin treated patients. Retrograde ejaculation is reversible upon discontinuation of treatment. Adverse Reactions observed in at least 2% of patients: The incidence of treatment-emergent adverse reactions listed in the following table were derived from two 12-week, multicenter, double-blind, placebo-controlled clinical studies of silodosin 8 mg daily in BPH patients. Adverse reactions that occurred in at least 2% of patients treated with silodosin and more frequently than with placebo are shown in Table 1. Table 1. Adverse Reactions Occurring in ≥ 2% of Patients in 12-week, Placebo-Controlled Clinical Trials In the two 12-week, placebo-controlled clinical trials, the following adverse events were reported by between 1% and 2% of patients receiving silodosin and occurred more frequently than with placebo: insomnia, PSA increased, sinusitis, abdominal pain, asthenia, and rhinorrhea. One case of syncope in a patient taking prazosin concomitantly and one case of priapism were reported in the silodosin treatment group. In a 9-month open-label safety study of silodosin, one case of Intraoperative Floppy Iris Syndrome (IFIS) was reported. 8.2 Postmarketing Experience The following adverse reactions have been identified during post approval use of silodosin. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure: Skin and subcutaneous tissue disorders: toxic skin eruption, purpura. Hepatobiliary disorders: jaundice, impaired hepatic function associated with increased transaminase values. 9. OVERDOSAGE Silodosin was eva luated at doses of up to 48 mg/day in healthy male subjects. The dose-limiting adverse event was postural hypotension. Should overdose of silodosin lead to hypotension, support of the cardiovascular system is of first importance. Restoration of blood pressure and normalization of heart rate may be accomplished by maintaining the patient in the supine position. If this measure is inadequate, administration of intravenous fluid should be considered. If necessary, vasopressors could be used, and renal function should be monitored and supported as needed. Dialysis is unlikely to be of significant benefit since silodosin is highly (97%) protein bound. 10. DRUG INTERACTIONS 10.1 Moderate and Strong CYP3A4 Inhibitors In a clinical metabolic inhibition study, a 3.8-fold increase in silodosin maximum plasma concentrations and 3.2-fold increase in silodosin exposure were observed with concurrent administration of a strong CYP3A4 inhibitor, 400 mg ketoconazole. Use of strong CYP3A4 inhibitors such as itraconazole or ritonavir may cause plasma concentrations of silodosin to increase. Concomitant administration of strong CYP3A4 inhibitors and silodosin is contraindicated [see Contraindications, Warnings and Precautions]. The effect of moderate CYP3A4 inhibitors on the pharmacokinetics of silodosin has not been eva luated. Concomitant administration with moderate CYP3A4 inhibitors (e.g., diltiazem, erythromycin, verapamil) may increase concentration of silodosin. Exercise caution and monitor patients for adverse events when co-administering silodosin with moderate CYP3A4 inhibitors. 10.2 Strong P-glycoprotein (P-gp) Inhibitors In vitro studies indicated that silodosin is a P-gp substrate. Ketoconazole, a CYP3A4 inhibitor that also inhibits P-gp, caused significant increase in exposure to silodosin. Inhibition of P-gp may lead to increased silodosin concentration. Silodosin is therefore not recommended in patients taking strong P-gp inhibitors such as cyclosporine. 10.3 Alpha-Blockers The pharmacodynamic interactions between silodosin and other alpha-blockers have not been determined. However, interactions may be expected, and silodosin should not be used in combination with other alpha-blockers [see Warnings and Precautions]. 10.4 Digoxin The effect of co-administration of silodosin and digoxin 0.25 mg/day for 7 days was eva luated in a clinical trial in 16 healthy males, aged 18 to 45 years. Concomitant administration of silodosin and digoxin did not significantly alter the steady state pharmacokinetics of digoxin. No dose adjustment is required. 10.5 PDE-5 Inhibitors Co-administration of silodosin with a single dose of 100 mg sildenafil or 20 mg tadalafil was eva luated in a placebo-controlled clinical study that included 24 healthy male subjects, 45 to 78 years of age. Orthostatic vital signs were monitored in the 12-hour period following concomitant dosing. During this period, the total number of positive orthostatic test results was greater in the group receiving silodosin plus a PDE-5 inhibitor compared with silodosin alone. No events of symptomatic orthostasis or dizziness were reported in subjects receiving silodosin with a PDE-5 inhibitor. 10.6 Other Concomitant Drug Therapy Antihypertensives The pharmacodynamic interactions between silodosin and antihypertensives have not been rigorously investigated in a clinical study. However, approximately one-third of the patients in clinical studies used concomitant antihypertensive medications with silodosin. The incidence of dizziness and orthostatic hypotension in these patients was higher than in the general silodosin population (4.6% versus 3.8% and 3.4% versus 3.2%, respectively). Exercise caution during concomitant use with antihypertensives and monitor patients for possible adverse events [see Warnings and Precautions]. Metabolic Interactions In vitro data indicate that silodosin does not have the potential to inhibit or induce cytochrome P450 enzyme systems. 10.7 Food Interactions The effect of a moderate fat, moderate calorie meal on silodosin pharmacokinetics was variable and decreased silodosin maximum plasma concentration (Cmax) by approximately 18 - 43% and exposure (AUC) by 4 - 49% across three different studies. Safety and efficacy clinical trials for silodosin were always conducted in the presence of food intake. Patients should be instructed to take silodosin with a meal to reduce risk of adverse events. 11. PHARMACOKINETICS  The pharmacokinetics of silodosin have been eva luated in adult male subjects with doses ranging from 0.1 mg to 24 mg per day. The pharmacokinetics of silodosin are linear throughout this dosage range. Absorption The pharmacokinetic characteristics of silodosin 8 mg once daily were determined in a multi- dose, open-label, 7-day pharmacokinetic study completed in 19 healthy, target-aged (≥ 45 years of age) male subjects. Table 2 presents the steady state pharmacokinetics of this study. Table 2. Mean (±SD) Steady State Pharmacokinetic Parameters in Healthy Males Following Silodosin 8 mg Once Daily with Food The absolute bioavailability is approximately 32%. Food Effect The maximum effect of food (i.e., co-administration with a high fat, high calorie meal) on the PK of silodosin was not eva luated. The effect of a moderate fat, moderate calorie meal was variable and decreased silodosin Cmax by approximately 18 - 43% and AUC by 4 - 49% across three different studies. Distribution Silodosin has an apparent volume of distribution of 49.5 L and is approximately 97% protein bound. Metabolism Silodosin undergoes extensive metabolism through glucuronidation, alcohol and aldehyde dehydrogenase, and cytochrome P450 3A4 (CYP3A4) pathways. The main metabolite of silodosin is a glucuronide conjugate (KMD-3213G) that is formed via direct conjugation of silodosin by UDP-glucuronosyltransferase 2B7 (UGT2B7). Co-administration with inhibitors of UGT2B7 (e.g., probenecid, valproic acid, fluconazole) may potentially increase exposure to silodosin. KMD-3213G, which has been shown in vitro to be active, has an extended half-life (approximately 24 hours) and reaches plasma exposure (AUC) approximately four times greater than that of silodosin. The second major metabolite (KMD-3293) is formed via alcohol and aldehyde dehydrogenases and reaches plasma exposures similar to that of silodosin. KMD-3293 is not expected to contribute significantly to the overall pharmacologic activity of silodosin. Excretion Following oral administration of 14C-labeled silodosin, the recovery of radioactivity after 10 days was approximately 33.5% in urine and 54.9% in feces. After intravenous administration, the plasma clearance of silodosin was approximately 10 L/hour. Special Populations Race No clinical studies specifically investigating the effects of race have been performed. Geriatric In a study comparing 12 geriatric males (mean age 69 years) and 9 young males (mean age 24 years), the exposure (AUC) and elimination half-life of silodosin were approximately 15% and 20%, respectively, greater in geriatric than young subjects. No difference in the Cmax of silodosin was observed [see Use in Specific Populations]. Pediatric Silodosin has not been eva luated in patients less than 18 years of age. Renal Impairment In a study with six subjects with moderate renal impairment, the total silodosin (bound and unbound) AUC, Cmax, and elimination half-life were 3.2-, 3.1-, and 2-fold higher, respectively, compared to seven subjects with normal renal function. The unbound silodosin AUC and Cmax were 2.0- and 1.5-fold higher, respectively, in subjects with moderate renal impairment compared to the normal controls. In controlled and uncontrolled clinical studies, the incidence of orthostatic hypotension and dizziness was greater in subjects with moderate renal impairment treated with 8 mg silodosin daily than in subjects with normal or mildly impaired renal function [see Contraindications, Warnings and Precautions and Use in Specific Populations]. Hepatic Impairment In a study comparing nine male patients with moderate hepatic impairment (Child-Pugh scores 7 to 9), to nine healthy male subjects, the single dose pharmacokinetic disposition of silodosin was not significantly altered in the patients with moderate hepatic impairment. No dosing adjustment is required in patients with mild or moderate hepatic impairment. The pharmacokinetics of silodosin in patients with severe hepatic impairment have not been studied [see Contraindications, Warnings and Precautions and Use in Specific Populations]. 12. HOW SUPPLIED/STORAGE AND HANDLING 1) How Available: a) Brand name: RAPAFLO, by WATSON LABS. b) Generic drugs: None. 2) How Supplied: White, opaque, hard gelatin 8 mg capsules. Cap is imprinted with “WATSON 152” in green. Body is imprinted with “8 mg” in green. 8 mg capsules are supplied in unit of use HDPE bottles of: • 30 capsules (NDC 52544-152-30) • 90 capsules (NDC 52544-152-19) 8 mg capsules are supplied in non-unit of use HDPE bottles of: • 1000 capsules (NDC 52544-152-10) Bottles of 30 and 90 capsules are supplied with child-resistant closures. White, opaque, hard gelatin 4 mg capsules. Cap is imprinted with “WATSON 151” in gold. Body is imprinted with “4 mg” in gold. 4 mg capsules are supplied in unit of use HDPE bottles of: • 30 capsules (NDC 52544-151-30) • 90 capsules (NDC 52544-151-19) Bottles of 30 and 90 capsules are supplied with child-resistant closures. 3) Storage: Store at 25°C (77°F); excursions permitted to 15-30°C (59-86°F). [See USP controlled room temperature.] Protect from light and moisture.