What is an example of an alpha-blocker for a female patient with a 5mm kidney stone?

Tamsulosin for a 5mm Kidney Stone in a Female Patient

Tamsulosin 0.4 mg daily is the alpha-blocker of choice for this patient with a 5mm distal ureteral stone, and should be offered regardless of sex, as the mechanism of ureteral smooth muscle relaxation is sex-independent. 1

Recommended Alpha-Blocker and Dosing

• Tamsulosin 0.4 mg once daily is the standard alpha-blocker for medical expulsive therapy (MET) 1, 2
• The medication works through alpha-1 receptor blockade, causing ureteral smooth muscle relaxation and facilitating stone passage 1
• Do not withhold tamsulosin from women based solely on FDA labeling for benign prostatic hyperplasia (BPH)—the mechanism for stone passage is sex-independent 1

Evidence for 5mm Stones

• For distal ureteral stones 5-10 mm in size, tamsulosin increases stone passage rates by an absolute 22-29% compared to placebo 1
• Stone expulsion rates improve to 81-87% with tamsulosin versus 61-79% with placebo for stones in this size range 1
• The number needed to treat is 4-5 patients for stones 5-10 mm 1
• Tamsulosin reduces time to stone expulsion by approximately 3 days and decreases pain episodes and analgesic requirements 1

Treatment Duration and Monitoring

• Continue tamsulosin for a maximum of 4-6 weeks from initial clinical presentation 1
• Monitor weekly for stone passage and complications during the first 2 weeks 1
• At weeks 2-4, obtain repeat imaging to assess stone position and hydronephrosis if no passage has occurred 1
• Do not exceed 6 weeks of conservative management, as complete unilateral ureteral obstruction beyond this timeframe risks irreversible kidney injury 1

Mandatory Discontinuation Criteria

• Stop tamsulosin immediately if signs of infection/sepsis develop 1
• Discontinue if declining renal function occurs 1
• Discontinue if refractory pain or obstruction requiring urgent intervention develops 1

Safety Considerations

• Counsel the patient about orthostatic hypotension, dizziness, and potential syncope—advise avoiding situations where injury could occur if syncope happens 2
• Adverse events are generally mild and comparable to placebo, with common side effects including dizziness and hypotension 1
• Use caution with concomitant CYP3A4 inhibitors (e.g., ketoconazole, erythromycin), CYP2D6 inhibitors (e.g., paroxetine), PDE5 inhibitors, warfarin, or other alpha-blockers 2
• In patients with sulfa allergy, use caution as allergic reactions have been rarely reported 2

Clinical Pitfalls to Avoid

• For stones ≤5 mm, tamsulosin provides no clinically meaningful benefit due to high spontaneous passage rates of 68-89% regardless of treatment—however, this patient has a 5mm stone at the threshold where benefit begins 1
• Ensure the stone is confirmed to be in the distal ureter on CT imaging before initiating tamsulosin 1
• The patient must have controlled pain, no sepsis, and adequate renal reserve to qualify for any observation period with MET 1