Silodosin

Q: Is Silodosin available over the counter?

Silodosin is a prescription medication. You will need a valid prescription from a licensed healthcare provider.

Prescription

商品名： Silodosin

剤形

Capsule

投与経路

ORAL

製造会社

Lupin Pharmaceuticals, Inc.

About This Medication

11 DESCRIPTION Silodosin capsule is a selective antagonist of alpha-1 adrenoreceptors. The chemical name of silodosin is 1-(3-Hydroxypropyl)-5-[(2 R )-2-({2-[2-(2,2,2-trifluoroethoxy)phenoxy]ethyl}amino) propyl]-2,3-dihydro-1 H -indole-7-carboxamide and the molecular formula is C 25 H 32 F 3 N 3 O 4 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°C to 109°C. It is freely soluble in acetic acid, freely soluble in alcohol, and insoluble in water. Each Silodosin 8 mg capsule for oral administration contains 8 mg silodosin, and the following inactive ingredients: magnesium stearate, mannitol and sodium lauryl sulfate. The size #1 hard gelatin capsules contain gelatin, sodium lauryl sulfate and titanium dioxide. The capsules are printed with edible ink containing FD&C Blue No. 2 Aluminum Lake, propylene glycol, shellac, titanium dioxide and yellow iron oxide. Each Silodosin 4 mg capsule for oral administration contains 4 mg silodosin, and the following inactive ingredients: magnesium stearate, mannitol and sodium lauryl sulfate. The size #3 hard gelatin capsules contain gelatin, sodium lauryl sulfate and titanium dioxide. The capsules are printed with edible ink containing propylene glycol, shellac and yellow iron oxide. Silodosin

有効成分

成分	含有量
Silodosin	-

適応症と用法

1 INDICATIONS AND USAGE Silodosin capsules, an alpha-1 adrenergic receptor antagonist, is indicated for the treatment of the signs and symptoms of benign prostatic hyperplasia (BPH). Silodosin capsule is not indicated for the treatment of hypertension. ( 1 ) Silodosin capsule, a selective alpha-1 adrenergic receptor antagonist, is indicated for the treatment of the signs and symptoms of benign prostatic hyperplasia (BPH) [see CLINICAL STUDIES ( 14 )] . Silodosin capsule is not indicated for the treatment of hypertension.

作用のしくみ

12.1 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.

用量と投与方法

2 DOSAGE AND ADMINISTRATION 8 mg capsules taken orally once daily with a meal. ( 2.1 ) 4 mg capsules taken orally once daily with a meal for those with moderate renal impairment [Creatinine Clearance (CCr) 30 mL/min to 50 mL/min]. ( 2.2 ) 2.1 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 [see CLINICAL PHARMACOLOGY ( 12.3 )] . 2.2 Dosage Adjustment in Special Populations Renal impairment: Silodosin capsule is contraindicated in patients with severe renal impairment (CCr < 30 mL/min). In patients with moderate renal impairment (CCr 30 mL/min to 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 mL/min to 80 mL/min) [see CONTRAINDICATIONS ( 4 ), WARNINGS AND PRECAUTIONS ( 5.2 ), USE IN SPECIFIC POPULATIONS ( 8.6 ) and CLINICAL PHARMACOLOGY ( 12.3 )]. Hepatic impairment: Silodosin capsule 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 ( 4 ), WARNINGS AND PRECAUTIONS ( 5.3 ), USE IN SPECIFIC POPULATIONS ( 8.7 ) and CLINICAL PHARMACOLOGY ( 12.3 )] .

Side Effects Overview

6 ADVERSE REACTIONS Most common adverse reactions (incidence ≥ 2%) are retrograde ejaculation, dizziness, diarrhea, orthostatic hypotension, headache, nasopharyngitis, and nasal congestion. ( 6 ) To report SUSPECTED ADVERSE REACTIONS, contact Lupin Pharmaceuticals, Inc. at 1-800-399-2561 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch . 6.1 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 years 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 Adverse Reactions Silodosin N = 466 n (%) Placebo N = 457 n (%) Retrograde Ejaculation 131 (28.1) 4 (0.9) Dizziness 15 (3.2) 5 (1.1) Diarrhea 12 (2.6) 6 (1.3) Orthostatic Hypotension 12 (2.6) 7 (1.5) Headache 11 (2.4) 4 (0.9) Nasopharyngitis 11 (2.4) 10 (2.2) Nasal Congestion 10 (2.1) 1 (0.2) 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. 6.2 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, skin rash, pruritus, and urticaria Hepatobiliary Disorders J aundice, impaired hepatic function associated with increased transaminase values Immune System Disorders Allergic-type reactions, not limited to skin reactions including swollen tongue and pharyngeal edema resulting in serious outcomes

警告と注意事項

5 WARNINGS AND PRECAUTIONS Postural hypotension, with or without symptoms (e.g., dizziness), may develop when beginning silodosin treatment. ( 5.1 ) In patients with moderate renal impairment, silodosin dose should be reduced to 4 mg once daily. ( 5.2 ) Silodosin should not be used in combination with other alpha-blockers. ( 5.5 ) Examine patients thought to have BPH prior to starting therapy with silodosin to rule out the presence of carcinoma of the prostate. ( 5.6 ) Inform patients planning cataract surgery to notify their ophthalmologist that they are taking silodosin because of the possibility of Intraoperative Floppy Iris Syndrome (IFIS). ( 5.7 ) 5.1 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 ( 6 ), USE IN SPECIFIC POPULATIONS ( 8.5 ), CLINICAL PHARMACOLOGY ( 12.2 ), and PATIENT COUNSELING INFORMATION ( 17 ) ] . 5.2 Renal Impairment In a clinical pharmacology study, plasma concentrations (AUC and C max ) 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 ( 8.6 ) and CLINICAL PHARMACOLOGY ( 12.3 )] . Silodosin is contraindicated in patients with severe renal impairment [see CONTRAINDICATIONS ( 4 )]. 5.3 Hepatic Impairment Silodosin has not been tested in patients with severe hepatic impairment, and therefore, should not be prescribed to such patients [see CONTRAINDICATIONS ( 4 ), USE IN SPECIFIC POPULATIONS ( 8.7 ) and CLINICAL PHARMACOLOGY ( 12.3 )] . 5.4 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 ( 7.1 )]. 5.5 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 ( 7.3 )]. 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 ( 6.1 ) and DRUG INTERACTIONS ( 7.6 )]. Caution is also advised when alpha-adrenergic blocking agents including silodosin are co-administered with PDE5 inhibitors. Alpha-adrenergic blockers and PDE5 inhibitors are both vasodilators that can lower blood pressure. Concomitant use of these two drug classes can potentially cause symptomatic hypotension [see DRUG INTERACTIONS ( 7.5 )]. 5.6 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. 5.7 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 ( 6.1 )]. 5.8 Laboratory Test Interactions No laboratory test interactions were observed during clinical evaluations. Treatment with silodosin for up to 52 weeks had no significant effect on prostate-specific antigen (PSA).

禁忌

4 CONTRAINDICATIONS Patients with severe renal impairment [Creatinine Clearance (CCr < 30 mL/min)]. ( 4 ) Patients with severe hepatic impairment (Child-Pugh score ≥ 10). ( 4 ) Concomitant administration with strong Cytochrome P450 3A4 (CYP3A4) inhibitors (e.g., ketoconazole, clarithromycin, itraconazole, ritonavir). ( 4 ) Patients with a history of hypersensitivity to silodosin or any of the ingredients of silodosin capsules. ( 4 ) 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 ( 7.1 )] Patients with a history of hypersensitivity to silodosin or any of the ingredients of silodosin capsules [see ADVERSE REACTIONS ( 6.2 ) and DESCRIPTION ( 11 )]

薬物動態

12.3 Pharmacokinetics The pharmacokinetics of silodosin have been evaluated 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 3 presents the steady state pharmacokinetics of this study. Table 3: Mean (±SD) Steady State Pharmacokinetic Parameters in Healthy Males Following Silodosin 8 mg Once Daily with Food C max (ng/mL) t max (hours) t 1/2 (hours) AUC ss (ng•hr/mL) 61.6 ± 27.54 2.6 ± 0.90 13.3 ± 8.07 373.4 ± 164.94 C max = maximum concentration, t max = time to reach C max , t 1/2 = elimination half-life, AUC ss = steady state area under the concentration-time curve Figure 1: Mean (±SD) Silodosin Steady State Plasma Concentration-Time Profile in Healthy Target-Aged Subjects 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 evaluated. The effect of a moderate fat, moderate calorie meal was variable and decreased silodosin C max by approximately 18% to 43% and AUC by 4% to 49% across three different studies. In a single-center, open-label, single-dose, randomized, two-period crossover study in twenty healthy male subjects age 21 years to 43 years under fed conditions, a study was conducted to evaluate the relative bioavailability of the contents of an 8 mg capsule (size #1) of silodosin sprinkled on applesauce compared to the product administered as an intact capsule. Based on AUC 0-24 and Cmax, silodosin administered by sprinkling the contents of a silodosin capsule onto a tablespoonful of applesauce was found to be bioequivalent to administering the capsule whole. 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 14 C-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 C max of silodosin was observed [see USE IN SPECIFIC POPULATIONS ( 8.5 )].

Frequently Asked Questions

1 INDICATIONS AND USAGE Silodosin capsules, an alpha-1 adrenergic receptor antagonist, is indicated for the treatment of the signs and symptoms of benign prostatic hyperplasia (BPH). Silodosin capsule is not indicated for the treatment of hypertension. ( 1 ) Silodosin capsule, a selective alpha-1 adrenergic receptor antagonist, is indicated for the treatment of the signs and symptoms of benign prostatic hyperplasia (BPH) [see CLINICAL STUDIES ( 14 )] . Silodosin capsule is not indicated for the treatment of hypertension.

2 DOSAGE AND ADMINISTRATION 8 mg capsules taken orally once daily with a meal. ( 2.1 ) 4 mg capsules taken orally once daily with a meal for those with moderate renal impairment [Creatinine Clearance (CCr) 30 mL/min to 50 mL/min]. ( 2.2 ) 2.1 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 …

5 WARNINGS AND PRECAUTIONS Postural hypotension, with or without symptoms (e.g., dizziness), may develop when beginning silodosin treatment. ( 5.1 ) In patients with moderate renal impairment, silodosin dose should be reduced to 4 mg once daily. ( 5.2 ) Silodosin should not be used in combination with other alpha-blockers. ( 5.5 ) Examine patients thought to have BPH prior to starting therapy with silodosin to rule out the presence of carcinoma of the prostate. ( 5.6 ) Inform patients …

4 CONTRAINDICATIONS Patients with severe renal impairment [Creatinine Clearance (CCr < 30 mL/min)]. ( 4 ) Patients with severe hepatic impairment (Child-Pugh score ≥ 10). ( 4 ) Concomitant administration with strong Cytochrome P450 3A4 (CYP3A4) inhibitors (e.g., ketoconazole, clarithromycin, itraconazole, ritonavir). ( 4 ) Patients with a history of hypersensitivity to silodosin or any of the ingredients of silodosin capsules. ( 4 ) Severe renal impairment (CCr < 30 mL/min) Severe hepatic impairment (Child-Pugh score ≥ 10) Concomitant administration …

Silodosin is a prescription medication. You will need a valid prescription from a licensed healthcare provider.

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References & Data Sources

• DailyMed — Silodosin drug label (National Library of Medicine)
• openFDA — Silodosin label data (U.S. Food & Drug Administration)
• RxNorm — RXCUI 809477 (NLM Normalized Drug Names)
• NDC Directory — Silodosin (FDA National Drug Code)

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データソース： DailyMed (NLM), openFDA, MFDS