Overview
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.
Mechanism of Action
12 CLINICAL PHARMACOLOGY 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. 12.
Indications
- 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.
Common Doses
- 8 mg
- 4 mg
- 30 mL
- 50 mL
Dosage
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.
Contraindications
- 4 CONTRAINDICATIONS Patients with severe renal impairment [Creatinine Clearance (CCr
Side Effects
- 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...
Interactions
- 7 DRUG INTERACTIONS Strong P-glycoprotein inhibitors (e.g., cyclosporine): Co-administration may increase plasma silodosin concentration. Concomitant use is not recommended. ( 7.2 ) Alpha-blockers: Interactions involving concomitant use have not been determined. However, interactions are expected and concomitant use is not recommended. ( 7.3 ) Concomitant use of PDE5 inhibitors with alpha-blockers including silodosin can potentially cause symptomatic hypotension. ( 5.5 , 7.5 ) 7.1 Moderate and Strong CYP3A4 Inhibitors In a clinical metabolic inhibition study, a 3.