silodosin

Contraindicated in:

Hypersensitivity;
Concurrent use of strong CYP3A4 inhibitors.
Severe renal impairment;
Severe hepatic impairment;

Use Cautiously in:

Cataract surgery (may cause intraoperative floppy iris syndrome);
Moderate renal impairment (↓ dose);
Geri: ↑risk of orthostatic hypotension in older adults;
Pedi: Safety and effectiveness not established in children.

Adv. Reactions/Side Effects ⬆ ⬇

CV: orthostatic hypotension

Derm: pruritus, rash, urticaria

GI: diarrhea

GU: retrograde ejaculation

Neuro: dizziness, headache

Misc: allergic reactions

Interactions ⬆ ⬇

Drug-drug:

Strong CYP3A4 inhibitors, including ketoconazole, clarithromycin, itraconazole, and ritonavir, significantly ↑ levels and risk of toxicity; concurrent use contraindicated.
Moderate CYP3A4 inhibitors, including diltiazem, erythromycin, and verapamil, may ↑ levels and risk of toxicity; use cautiously.
Concurrent use with antihypertensives (including calcium channel blockers and thiazide diuretics), other alpha blockers, and PDE-5 inhibitors (including sildenafil, tadalafil, and vardenafil) ↑ the risk of dizziness and orthostatic hypotension.
P-glycoprotein inhibitors, including cyclosporine, may ↑ levels and risk of toxicity; concurrent use not recommended.

Availability ⬆ ⬇

(Generic available)

Capsules: 4 mg; 8 mg

Route/Dosage ⬆ ⬇

PO (Adults ): 8 mg once daily.

Renal Impairment

PO (Adults ): CCr 30–50 mL/min: 4 mg once daily.

US Brand Names ⬆ ⬇

Action ⬆ ⬇

Blocks postsynaptic alpha₁-adrenergic receptors. Decreases contractions in the smooth muscle of the prostatic capsule.

Therapeutic effects:

Decreased signs and symptoms of BPH (urinary urgency, hesitancy, nocturia).

Classifications ⬆ ⬇

Therapeutic Classification: benign prostatic hyperplasia bph agents

Pharmacologic Classification: alpha adrenergic blockers

Pharmacokinetics ⬆ ⬇

Absorption: 32% absorbed following oral administration.

Distribution: Well distributed to tissues.

Protein Binding: 97%.

Metabolism/Excretion: Extensively metabolized by the liver by the CYP3A4 isoenzyme, UGT2B7, and other metabolic pathways; 33.5% excreted in urine and 54.9% in feces.

Half-Life: 13.3 hr.

Time/Action Profile ⬆ ⬇

(↓ in BPH symptoms)

ROUTE	ONSET	PEAK	DURATION
PO	rapid	24 hr	24 hr*

*Following discontinuation.

Patient/Family Teaching ⬆ ⬇

Explain the purpose and side effects of silodosin. Instruct to take as directed with the same meal each day. Emphasize the importance of continuing to take this medication, even if feeling well. If a dose is missed, take as soon as remembered unless almost time for next dose. Do not double doses. Advise patient to read Patient Information before starting therapy and with each Rx refill in case of changes.
- Emphasize the importance of follow-up exams to evaluate effectiveness of medication.
- May cause dizziness. Caution patient to avoid driving or other activities requiring alertness until response to the medication is known.
- Caution patient to avoid sudden changes in position to ↓ orthostatic hypotension, especially patients with low BP or concurrently taking antihypertensives. Assess risk for falls; instruct patient and family in preventing falls at home.
- Instruct patient to notify health care provider of all Rx or OTC medications, vitamins, or herbal products being taken and consult health care provider before taking any new medications, especially cough, cold, or allergy remedies.
- Instruct patient to notify health care provider of medication regimen before any surgery. Patients planning cataract surgery should notify ophthalmologist of silodosin therapy prior to surgery.

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Indications ⬇

Contraind./Precautions ⬆ ⬇