Silodosin

CrCl (mL/min)	Dosage
< 30	Contraindicated.
30-50	4 mg daily, may be adjusted to 8 mg daily after 1 week depending on patient response.

Severe (Child-Pugh class C): Contraindicated.

Should be taken with food.

Severe renal and hepatic impairment. Patient treated with CYP3A4 inhibitors and α-blockers.

Patient with orthostatic hypotension. Patients undergoing cataract surgery. Prostate cancer should be ruled out prior to initiation of silodosin. Moderate renal and mild to moderate hepatic impairment. Not indicated for use in women and children.

Significant: Orthostatic hypotension.
Cardiac disorders: Tachycardia.
Gastrointestinal disorders: Diarrhoea, abdominal pain, dry mouth.
Nervous system disorders: Dizziness, headache.
Psychiatric disorders: Insomnia.
Renal and urinary disorders: UTI.
Reproductive system and breast disorders: Abnormal ejaculation (e.g. retrograde ejaculation, decreased libido).
Respiratory, thoracic and mediastinal disorders: Nasopharyngitis, nasal congestion, influenza, sinusitis, rhinitis.

PO: B

This drug may cause postural hypotension (with or without symptoms e.g. dizziness) and syncope, if affected, do not drive or operate machinery.

Monitor blood pressure and urinary symptoms.

Symptoms: Postural hypotension. Management: Maintain patient in supine position. Induce vomiting or consider gastric lavage. Provide cardiovascular support if overdose leads to hypotension.

Silodosin plasma concentration may be increased by moderate CYP3A4 inhibitors (e.g. diltiazem, erythromycin, verapamil), P-glycoprotein transport inhibitors (e.g. ciclosporin) and uridine diphosphate-glucuronosyltransferase (e.g. fluconazole, probenecid, valproic acid). Concomitant use with antihypertensive agents may increase risk of adverse effect (orthostatic hypotension). Concomitant use with PDE-5 inhibitors (e.g. sildenafil) may lead to symptomatic hypotension.
Potentially Fatal: Significantly increased plasma concentration with strong CYP3A4 inhibitor (e.g. clarithromycin, itraconazole, ketoconazole, ritonavir). Additive cardiovascular effects with other α-adrenergic blockers.

Description:
Mechanism of Action: Silodosin is a selective antagonist of post-synaptic α₁-adrenoreceptors in the prostate and bladder. Blockade of α₁-adrenoreceptors causes relaxation of smooth muscle resulting to improved urine flow and reduced BPH symptoms.
Pharmacokinetics:
Absorption: Rapidly absorbed. Bioavailability: Approx 32%. Time to peak plasma concentration: Approx 3 hours.
Distribution: Volume of distribution: 49.5 L. Plasma protein binding: Approx 97%.
Metabolism: Metabolised in the liver via glucuronidation (UGT2B7), alcohol and aldehyde dehydrogenase and oxidative pathways, primarily CYP3A4 to the main metabolite, KMD-3213G (glucuronide conjugate).
Excretion: Via faeces (55%) and urine (34%). Elimination half-life: Approx 13 hours (silodosin); approx 24 hours (KMD-3213G).

Source: National Center for Biotechnology Information. PubChem Database. Silodosin, CID=5312125, https://pubchem.ncbi.nlm.nih.gov/compound/Silodosin (accessed on Jan. 23, 2020)

Store below 30°C. Protect from light and moisture.

Thuốc trị các rối loạn ở bàng quang & tuyến tiền liệt

G04CA04 - silodosin ; Belongs to the class of alpha-adrenoreceptor antagonists. Used in the treatment of benign prostatic hypertrophy.

Anon. Silodosin. AHFS Clinical Drug Information [online]. Bethesda, MD. American Society of Health-System Pharmacists, Inc. https://www.ahfscdi.com. Accessed 21/05/2019.

Anon. Silodosin. Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 21/05/2019.

Buckingham R (ed). Silodosin. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 21/05/2019.

Silodosin Capsule (Amneal Pharmaceuticals NY LLC). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/. Accessed 21/05/2019.

Urief Fim-Coated Tablets 4 mg (Kissei Pharmaceutical Co., Ltd.). MIMS Malaysia. http://www.mims.com/malaysia. Accessed 30/05/2019.

Urorec 4mg Hard Capsules (Recordati Ireland Ltd.). European Medicines Agency [online]. Accessed 21/05/2019.