Alpha-adrenergic blockers for prostatic disorders
Updated · Methodology
First line
First-line medical therapy for BPH per EAU 2023 and AUA guidelines. Dose is 0.4 mg once daily. Effect begins within 1–2 weeks. Improves Qmax (peak urinary flow rate) by 1–3 mL/s and reduces IPSS score by 3–5 points. Does not reduce prostate volume – a 5-alpha-reductase inhibitor (finasteride, dutasteride) is added when prostate volume exceeds 40 mL.
ICD-10: N40 · ICD-11: GA90
Adjunct
Adjunctive therapy to facilitate passage of distal ureteral stones 5–10 mm in size. Meta-analyses show tamsulosin accelerates stone passage and reduces analgesic requirements. EAU 2023 guidelines permit tamsulosin 0.4 mg for distal ureteral stones. No proven benefit for stones under 5 mm.
Sources
ICD-10: N20.1 · ICD-11: GB70.1
The drug is promoted for these uses outside international guidelines. Each entry below is analyzed against AEMPS, FDA, EMA, Cochrane and major RCTs.
Not recommended
Tamsulosin is a selective α1A-adrenergic blocker. It is prescribed for men with benign prostatic hyperplasia (BPH) for improving urination (AUA 2023, AEMPS Ficha Técnica). Tamsulosin is prescribed to men without confirmed BPH diagnosis for anti-aging improvement of urination. In men without BPH, no clinical studies of prophylactic use exist. The drug can cause orthostatic hypotension (especially in older adults, fall risk), retrograde ejaculation, and abnormalities of the ocular choroid with intraoperative cataract surgery complications (intraoperative floppy iris syndrome – requires informing the ophthalmologist). If tamsulosin was prescribed without confirmed BPH, consider seeking a second opinion.
Selective alpha-1A adrenergic receptor antagonist. Relaxes smooth muscle in the prostate and bladder neck, improving urine flow. Minimal action on vascular alpha-1B receptors, so orthostatic hypotension is less frequent than with non-selective alpha-blockers such as doxazosin and terazosin.
This drug is intended for men. Not used in women.
Tamsulosin is indicated in men with benign prostatic hyperplasia, so breastfeeding compatibility rarely arises in practice. When a woman has received tamsulosin for an off-label indication, no data exist on human milk transfer and Hale has not assigned a category. The urology team picks alternatives if needed.
Reference information, not a clinical decision. Discuss feeding pauses or changes with your physician or an IBCLC.
6 pairs found. Sorted from critical to minor.
Mechanism
Ketoconazole is a potent CYP3A4 inhibitor – the main tamsulosin metabolic route. Tamsulosin plasma levels rise 2- to 3-fold; orthostatic hypotension and syncope emerge.
Symptoms
Sudden blood pressure drop on standing, syncope, dizziness. Older patients: fall and fracture risk.
Management
The AEMPS label for tamsulosin says the drug must not be given with strong CYP3A4 inhibitors such as ketoconazole. Avoid the combination. Alternative antifungals: terbinafine for dermatophytosis or echinocandins for systemic mycoses. Alternative for benign prostatic hyperplasia: a 5α-reductase inhibitor (finasteride, dutasteride).
Sources
Mechanism
Clarithromycin blocks CYP3A4 – the main tamsulosin metabolic route. Tamsulosin plasma levels rise; orthostatic hypotension emerges.
Symptoms
Sudden blood pressure drop on standing, syncope, dizziness. Older patients: fall and fracture risk.
Management
During clarithromycin therapy, halve tamsulosin temporarily or use an alternative: finasteride/dutasteride (minimal CYP3A4 dependence). Alternative antibiotics: azithromycin or doxycycline.
Sources
Mechanism
Tamsulosin is a CYP3A4 substrate. Ritonavir is a potent CYP3A4 inhibitor. Tamsulosin plasma levels rise 5-fold or more; orthostatic hypotension and syncope emerge.
Symptoms
Sudden blood pressure drop on standing, syncope, dizziness. Older patients: fall and fracture risk.
Management
Avoid the combination. Alternative for benign prostatic hyperplasia on ritonavir: a 5α-reductase inhibitor (finasteride, dutasteride; minimal CYP3A4 dependence) or an α1-blocker with less CYP3A4 dependence (alfuzosin with caution).
Sources
Mechanism
Additive orthostatic hypotension. Tamsulosin (α1-blocker) directly vasodilates; alprazolam mildly lowers BP and amplifies the orthostatic response.
Symptoms
Postural dizziness, syncope, fatigue. Older patients: fall and fracture risk. Sedation, fatigue, slowed reactions, impaired coordination. In older patients: fall and fracture risk. Driving and operating machinery: accident risk.
Management
On starting the combination, take tamsulosin in the evening (to minimise daytime weakness) and alprazolam at bedtime. In older patients, start alprazolam at 0.125 mg. Check standing/sitting BP at 1 and 2 weeks. With pronounced orthostatic hypotension, consider switching tamsulosin to silodosin (minimal BP effect).
Mechanism
Tamsulosin is broken down in the liver mainly by the CYP3A4 and CYP2D6 enzymes (tamsulosin labels). Amiodarone and its metabolite desethylamiodarone inhibit both enzymes and can raise the levels of their substrates (amiodarone SmPC); the US Food and Drug Administration () classifies amiodarone as a weak inhibitor of CYP3A4 and CYP2D6 (FDA table of CYP inhibitors). There are no data on how much tamsulosin levels rise with this combination. Tamsulosin itself can lower blood pressure, rarely to the point of fainting (tamsulosin SmPC), and higher levels may enhance this effect.
Symptoms
Dizziness and weakness on standing, rarely fainting (tamsulosin SmPC). In older patients, these episodes increase the risk of falls.
Management
Use tamsulosin with caution together with cytochrome P450 inhibitors, which include amiodarone (tamsulosin label of the US Food and Drug Administration, ). The FDA label stresses caution especially at doses above 0.4 mg a day; in Spain tamsulosin is taken as 0.4 mg once daily (tamsulosin SmPC). Warn the patient to sit or lie down at the first signs of orthostatic hypotension, such as dizziness or weakness, until they pass (tamsulosin SmPC).
Sources
Mechanism
Additive orthostatic hypotension. Both block α1-adrenoceptors: tamsulosin selectively (for the prostate), amitriptyline systemically. Effects add up.
Symptoms
Postural dizziness, syncope, fatigue. Older patients: fall and fracture risk.
Management
On the combination, begin amitriptyline at 10 mg at bedtime. In older patients, do not exceed 25 mg/day. Take tamsulosin in the evening. Check standing/sitting BP at 1–2 weeks. For neuropathic pain, alternatives: gabapentin or pregabalin.
Sources
Verbatim lines from the interaction sections, in the language of the label
«La administración concomitante de hidrocloruro de tamsulosina con inhibidores potentes del CYP3A4 pueden producir un aumento de la exposición a hidrocloruro de tamsulosina. La administración…»AEMPS, section 4.5 · Open on CIMA
«DRUG INTERACTIONS: • Tamsulosin hydrochloride capsules 0.4 mg should not be used with strong inhibitors of CYP3A4 (e.g., ketoconazole). Tamsulosin hydrochloride capsules should be used with caution…»FDA, section 7 · Open on DailyMed
«Cytochrome P450 Inhibition: Strong and Moderate Inhibitors of CYP3A4 or CYP2D6 Tamsulosin is extensively metabolized, mainly by CYP3A4 and CYP2D6. Concomitant treatment with ketoconazole (a strong…»FDA, section 7 · Open on DailyMed
«Cytochrome P450 Inhibition: Strong and Moderate Inhibitors of CYP3A4 or CYP2D6 Tamsulosin is extensively metabolized, mainly by CYP3A4 and CYP2D6. Concomitant treatment with ketoconazole (a strong…»FDA, section 7 · Open on DailyMed
«DRUG INTERACTIONS: • Tamsulosin hydrochloride capsules 0.4 mg should not be used with strong inhibitors of CYP3A4 (e.g., ketoconazole). Tamsulosin hydrochloride capsules should be used with caution…»FDA, section 7 · Open on DailyMed
«La administración concomitante de hidrocloruro de tamsulosina con inhibidores potentes del CYP3A4 pueden producir un aumento de la exposición a hidrocloruro de tamsulosina. La administración…»AEMPS, section 4.5 · Open on CIMA
«DRUG INTERACTIONS: • Tamsulosin hydrochloride capsules 0.4 mg should not be used with strong inhibitors of CYP3A4 (e.g., ketoconazole). Tamsulosin hydrochloride capsules should be used with caution…»FDA, section 7 · Open on DailyMed
«PDE5 Inhibitors: Caution is advised when alpha adrenergic blocking agents including tamsulosin hydrochloride are co-administered with PDE5 inhibitors. Alpha-adrenergic blockers and PDE5 inhibitors…»FDA, section 7 · Open on DailyMed
«DRUG INTERACTIONS: • Tamsulosin hydrochloride capsules 0.4 mg should not be used with strong inhibitors of CYP3A4 (e.g., ketoconazole). Tamsulosin hydrochloride capsules should be used with caution…»FDA, section 7 · Open on DailyMed
«Warfarin: A definitive drug-drug interaction study between tamsulosin hydrochloride and warfarin was not conducted. Results from limited in vitro and in vivo studies are inconclusive. Caution should…»FDA, section 7 · Open on DailyMed
«In vitro , la fracción libre de tamsulosina en plasma humano, no se ve modificada por diazepam, propranolol, triclormetiazida, clormadinona, amitriptilina, diclofenaco, glibenclamida, simvastatina ni…»AEMPS, section 4.5 · Open on CIMA
«No se han observado interacciones cuando hidrocloruro de tamsulosina se ha administrado junto con atenolol, enalapril, o teofilina.»AEMPS, section 4.5 · Open on CIMA
«Nifedipine, Atenolol, Enalapril: Dosage adjustments are not necessary when tamsulosin hydrochloride capsules are administered concomitantly with nifedipine, atenolol, or enalapril [see Clinical…»FDA, section 7 · Open on DailyMed
«In vitro , la fracción libre de tamsulosina en plasma humano, no se ve modificada por diazepam, propranolol, triclormetiazida, clormadinona, amitriptilina, diclofenaco, glibenclamida, simvastatina ni…»AEMPS, section 4.5 · Open on CIMA
«In vitro , la fracción libre de tamsulosina en plasma humano, no se ve modificada por diazepam, propranolol, triclormetiazida, clormadinona, amitriptilina, diclofenaco, glibenclamida, simvastatina ni…»AEMPS, section 4.5 · Open on CIMA
«Digoxin and Theophylline: Dosage adjustments are not necessary when a tamsulosin hydrochloride capsule is administered concomitantly with digoxin or theophylline [see Clinical Pharmacology (12.3) ] .»FDA, section 7 · Open on DailyMed
«No se han observado interacciones cuando hidrocloruro de tamsulosina se ha administrado junto con atenolol, enalapril, o teofilina.»AEMPS, section 4.5 · Open on CIMA
«Nifedipine, Atenolol, Enalapril: Dosage adjustments are not necessary when tamsulosin hydrochloride capsules are administered concomitantly with nifedipine, atenolol, or enalapril [see Clinical…»FDA, section 7 · Open on DailyMed
«El uso concomitante con cimetidina aumenta las concentraciones plasmáticas de tamsulosina, mientras que la furosemida las disminuye, pero no debe modificarse la posología, dado que la concentración…»AEMPS, section 4.5 · Open on CIMA
«Furosemide: Tamsulosin hydrochloride capsules had no effect on the pharmacodynamics (excretion of electrolytes) of furosemide. While furosemide produced an 11% to 12% reduction in tamsulosin…»FDA, section 7 · Open on DailyMed
«In vitro , la fracción libre de tamsulosina en plasma humano, no se ve modificada por diazepam, propranolol, triclormetiazida, clormadinona, amitriptilina, diclofenaco, glibenclamida, simvastatina ni…»AEMPS, section 4.5 · Open on CIMA
«Nifedipine, Atenolol, Enalapril: Dosage adjustments are not necessary when tamsulosin hydrochloride capsules are administered concomitantly with nifedipine, atenolol, or enalapril [see Clinical…»FDA, section 7 · Open on DailyMed
«La administración concomitante de hidrocloruro de tamsulosina con paroxetina, un inhibidor potente del CYP2D6, provocó que la C máx y el AUC de tamsulosina aumentasen en un factor de 1,3 y 1,6…»AEMPS, section 4.5 · Open on CIMA
«In vitro , la fracción libre de tamsulosina en plasma humano, no se ve modificada por diazepam, propranolol, triclormetiazida, clormadinona, amitriptilina, diclofenaco, glibenclamida, simvastatina ni…»AEMPS, section 4.5 · Open on CIMA
«In vitro , la fracción libre de tamsulosina en plasma humano, no se ve modificada por diazepam, propranolol, triclormetiazida, clormadinona, amitriptilina, diclofenaco, glibenclamida, simvastatina ni…»AEMPS, section 4.5 · Open on CIMA
«No se han observado interacciones cuando hidrocloruro de tamsulosina se ha administrado junto con atenolol, enalapril, o teofilina.»AEMPS, section 4.5 · Open on CIMA
«Digoxin and Theophylline: Dosage adjustments are not necessary when a tamsulosin hydrochloride capsule is administered concomitantly with digoxin or theophylline [see Clinical Pharmacology (12.3) ] .»FDA, section 7 · Open on DailyMed
«In vitro , la fracción libre de tamsulosina en plasma humano, no se ve modificada por diazepam, propranolol, triclormetiazida, clormadinona, amitriptilina, diclofenaco, glibenclamida, simvastatina ni…»AEMPS, section 4.5 · Open on CIMA
«Agentes antihipertensivos (por ejemplo, diuréticos) y otros medicamentos que puedan reducir la presión arterial (por ejemplo, nitratos, antidepresivos tricíclicos, anestésicos, ingesta aguda de…»AEMPS, section 4.5 · Open on CIMA
«Potential for Pharmacodynamic Interactions with Tadalafil Tablets: Alpha-Blockers — Caution is advised when PDE5 inhibitors are coadministered with alpha-blockers. PDE5 inhibitors, including…»FDA, section 7 · Open on DailyMed
«Estudios in vivo: Por ello, el tratamiento concomitante sólo debe iniciarse si el paciente está estabilizado con su tratamiento alfabloqueante. En los pacientes estabilizados con el tratamiento…»AEMPS, section 4.5 · Open on CIMA
«Potential for Pharmacodynamic Interactions with Vardenafil: Caution is advised when PDE5 inhibitors are co-administered with alpha-blockers. PDE5 inhibitors, including vardenafil and alpha-adrenergic…»FDA, section 7 · Open on DailyMed
«En un pequeño estudio (N=24) de dos semanas de duración en hombres sanos, dutasterida (0,5 mg) no afectó a la farmacocinética de tamsulosina o terazosina. Además, en este estudio no se observó…»AEMPS, section 4.5 · Open on CIMA
«Alpha-adrenergic Antagonists: The administration of dutasteride in combination with tamsulosin or terazosin has no effect on the steady-state pharmacokinetics of either alpha-adrenergic antagonist…»FDA, section 7 · Open on DailyMed
«Urológicos: Alfuzosina, Silodosina, Tadalafilo (disfunción eréctil e hiperplasia benigna de próstata), Tamsulosina, Tolterodina»AEMPS, section 4.5 · Open on CIMA
«DRUG INTERACTIONS: Drug interaction studies were conducted in adult patients to investigate the effect of coadministered drugs on the pharmacokinetics of mirabegron and the effect of mirabegron on…»FDA, section 7 · Open on DailyMed
«En los estudios de interacción realizados en un número limitado de voluntarios sanos, no se notificaron tales efectos ni con alfuzosina ni con tamsulosina.»AEMPS, section 4.5 · Open on CIMA
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Tamsulosin is evaluated for the following indications with varying evidence strength: Benign prostatic hyperplasia (evidence tier A), Medical expulsive therapy for ureteral stones (evidence tier B), Anti-aging and longevity (evidence tier F). See the full indication matrix with dosing and citations above on this page.
Common side effects of Tamsulosin (≥ 1 in 100): Retrograde ejaculation (most common side effect – up to 10%), Dizziness, Rhinitis, nasal congestion, Asthenia. See the Safety section for uncommon and serious reactions.
This drug is intended for men. Not used in women.
Tamsulosin is indicated in men with benign prostatic hyperplasia, so breastfeeding compatibility rarely arises in practice. When a woman has received tamsulosin for an off-label indication, no data exist on human milk transfer and Hale has not assigned a category. The urology team picks alternatives if needed.
Tamsulosin is contraindicated in: Hypersensitivity to tamsulosin; History of orthostatic hypotension; Severe hepatic impairment. Full list in the Safety section.
Direct links to regulator labels. Open in a new tab.
Tolterodine, Trospium, Vardenafil, Dutasteride, Fesoterodine, Propiverine, Sildenafil, Dutasteride + Tamsulosin