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Silodosin Promotes Rapid Improvement of Irritative and Obstructive Urinary Symptoms in Men With Benign Prostatic Hyperplasia
Marc C. Gittelman, MD1, Lawrence Hill, RPh, PharmD2, Weining Volinn, MS2, Gary Hoel, PhD2.
1South Florida Medical Research, Aventura, FL, USA, 2Watson Laboratories, Inc., Salt Lake City, UT, USA.

BACKGROUND: Combined results of 2 randomized, double-blind, placebo-controlled US studies demonstrated that silodosin promoted rapid improvement in total International Prostate Symptom Score (IPSS) in men with moderate to severe urinary symptoms related to benign prostatic hyperplasia (BPH). In a secondary analysis of the combined data, changes in responses to each question on the IPSS questionnaire were analyzed separately.
METHODS: Symptoms of patients (age ≥50 years; IPSS ≥13) receiving 8 mg silodosin (n=466) or placebo (n=457) once daily for 12 weeks were evaluated during clinical visits at weeks 0 (baseline), 1, 2, 4, and 12, and by telephone interview at treatment day 3 or 4 (week 0.5). The IPSS questions address these symptoms: emptying (Q1), frequency (Q2), intermittency (Q3), urgency (Q4), weak stream (Q5), straining (Q6), and nocturia (Q7). Responses were scored on a 6-point scale; Q1-Q6 were scored from “not at all” to “almost always,” Q7 was scored “none” to “5 or more times per night.” The significance of differences (silodosin vs placebo) in treatment effects was determined by analysis of covariance.
RESULTS: For each IPSS question, both treatment groups (silodosin and placebo) had similar mean IPSS scores at baseline. For both groups, baseline scores were Q1, 3.1; Q2, 3.5; Q3, 3.1; Q4, 3.0; Q5, 3.6; Q6, 2.2; Q7, 2.8. For each question, silodosin-related symptom improvement at last observation was significantly greater than corresponding symptom improvement associated with placebo (Table). For Q1 to Q6, silodosin-related symptom improvement at week 0.5 was significantly greater than placebo-associated improvement at week 0.5 (Table). Improvement in Q7 (nocturia) with silodosin vs placebo was significant at week 1 (Table).
CONCLUSIONS: Treatment with silodosin caused rapid and sustained improvement of all irritative and obstructive BPH-related symptoms assessed by the IPSS questionnaire. Silodosin treatment led to statistically significant improvement (vs placebo) in all symptoms within 1 week of treatment.

Symptom Improvement by IPSS Question
Irritative SymptomsIrritative SymptomsIrritative SymptomsIrritative SymptomsObstructive SymptomsObstructive SymptomsObstructive SymptomsObstructive Symptoms
Change from baselineSilodosin (n=466)Placebo (n=457)P valueChange from baselineSilodosin (n=466)Placebo (n=457)P value
Q2 Wk 0.5−0.5 (1.08)−0.3 (0.96).0002Q1 Wk 0.5−0.6 (1.14)−0.3 (0.97)<.0001
Q2 Last observation carried forward (LOCF)−0.9 (1.34)−0.5 (1.16)<.0001Q1 LOCF−0.9 (1.42)−0.6 (1.22)<.0001
Q4 Wk 0.5−0.4 (1.21)−0.3 (1.14).0075Q3 Wk 0.5−0.7 (1.19)−0.4 (1.10).0002
Q4 LOCF−0.8 (1.36)−0.4 (1.27)<.0001Q3 LOCF−1.1 (1.41)−0.6 (1.33)<.0001
Q7 Wk 0.5−0.4 (1.06)−0.3 (1.03).0968Q5 Wk 0.5−0.8 (1.29)−0.4 (1.03)<.0001
Q7 Wk 1−0.5 (1.07)−0.3 (1.05).0091Q5 LOCF−1.1 (1.41)−0.5 (1.21)<.0001
Q7 LOCF−0.6 (1.14)−0.4 (1.15).0037Q6 Wk 0.5−0.7 (1.16)−0.3 (1.21)<.0001
Q6 LOCF−0.9 (1.32)−0.5 (1.24)<.0001

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