Alpha-Blockers

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Continuing Education Activity

Alpha-blockers are medications used to manage essential hypertension, benign prostatic hyperplasia, and pheochromocytoma. These drugs work by modulating the sympathetic nervous system via alpha-adrenergic receptors, which influence vascular tone and norepinephrine release. Alpha-blockers fall into 3 categories—nonselective alpha-blockers and selective alpha-1 and alpha-2 blockers. 

Nonselective alpha-blockers may cause adverse effects such as hypotension, weakness, tachycardia, and tremulousness. Selective alpha-1 blockers are less likely to produce systemic effects such as tachycardia and tremulousness but are associated with adverse effects, including first-dose hypotension, syncope, dizziness, and headache due to their vasodilatory action and relaxation of vascular smooth muscle. This activity reviews the indications, contraindications, mechanisms of action, adverse events, and other key elements of alpha-blocker therapy in the clinical setting. This activity also focuses on the essential criteria for interprofessional healthcare team members to collaborate and treat patients with these conditions.

Objectives:

  • Identify the appropriate indications for alpha-blocker use, including hypertension, benign prostatic hyperplasia, and pheochromocytoma.

  • Assess the risk of adverse effects, such as orthostatic hypotension, tachycardia, and syncope, especially in patients starting alpha-blocker therapy.

  • Apply evidence-based guidelines to monitor and manage patients on alpha-blockers, adjusting treatment as needed for efficacy and safety.

  • Collaborate with interprofessional healthcare providers, including physicians, pharmacists, and nurses, to optimize patient care and minimize the risk of adverse outcomes related to alpha-blocker therapy.

Indications

Alpha-blockers are classified into 3 categories, as mentioned below.

Nonselective Alpha-Blockers

Nonselective alpha-blockers (alpha-1 and alpha-2), such as phenoxybenzamine and phentolamine, are approved by the Food and Drug Administration (FDA) for managing pheochromocytoma.

Phenoxybenzamine: Phenoxybenzamine is an irreversible alpha-blocker. Both medications are used intraoperatively to control hypertensive crises before and during pheochromocytoma surgery.[1][2] Please see StatPearls' companion resource, "Perioperative Management of Pheochromocytoma," for more information.

Phentolamine: Phentolamine is a reversible alpha-blocker and is occasionally used to treat cocaine-induced cardiovascular complications.[3][4] In these cases, β-blockers are less favorable due to the risk of unopposed α-adrenergic receptor-mediated coronary vasoconstriction and hypertension. Phentolamine is recommended for patients with ST-elevation myocardial infarction (STEMI) or cocaine-induced chest pain that does not respond to first-line treatments such as benzodiazepines and nitroglycerine.[5] In these situations, phentolamine has been shown to reverse ST elevations effectively.

Phentolamine is also a component of "Trimix," which is a standardized compounded combination of alprostadil, papaverine, and phentolamine used for intracavernosal injection therapy in male erectile dysfunction.[5][6][7][8] Please see StatPearls' companion resource, "Erectile Dysfunction," for more information.

Selective Alpha-Blockers

Selective alpha-1 blockers: Selective alpha-1 blockers can be identified by the suffix "-osin" and include medications such as alfuzosin, doxazosin, prazosin, silodosin, tamsulosin, and terazosin. These drugs are FDA-approved for the treatment of benign prostatic hyperplasia (BPH) and hypertension. Doxazosin, prazosin, and terazosin are examples of selective alpha-1 adrenergic antagonists used for essential hypertension, although they are considered second-line agents due to adverse effects, particularly orthostatic hypotension.[9]

Although these medications are effective for BPH, they are not the preferred alpha-blockers for managing symptomatic prostatic hyperplasia due to their adverse effects. Recommended alpha-blockers for BPH include alfuzosin, tamsulosin, and silodosin, which have relatively minimal orthostatic adverse effects and are considered first-line agents for this condition.[10] 

Selective alpha-2 blockers: Selective alpha-2 blockers include yohimbine and idazoxan. 

  • Yohimbine: This medication has been used historically to treat male erectile dysfunction; however, its clinical effectiveness has not been conclusively established, and it is not currently FDA-approved for any indication. In the United States, yohimbine has been discontinued as a prescription drug.[11][12] This medication has been replaced by more effective treatments for erectile dysfunction, such as sildenafil and tadalafil, which have demonstrated proven clinical efficacy. Please see StatPearls' companion resource, "Erectile Dysfunction," for more information.

Recent evidence suggests that low doses of yohimbine may enhance athletic performance.[13][14] However, the bioavailability of yohimbine varies greatly between individuals, and the drug can sometimes exhibit unexpected potency. Higher doses have been associated with significant adverse effects, and no standardized or widely recognized dosing schedules have been established.[13]

  • Idazoxan: This medication is primarily used in research settings, as it has not yet been established for any clinical role.[11]

Mechanism of Action

Alpha-blockers exert their pharmacological effects by modulating the sympathetic nervous system. The 2 primary types of alpha-adrenergic receptors include alpha-1 and alpha-2.

Alpha-1 Adrenergic Receptors

Most alpha-1 adrenergic receptors are located on the vascular smooth muscle in areas such as the skin, gastrointestinal sphincters, kidneys, and brain. When activated by catecholamines, such as epinephrine and norepinephrine, these receptors induce vasoconstriction, which in turn increases systemic arterial blood pressure and peripheral resistance. Norepinephrine has a higher affinity for these receptors than epinephrine.

Alpha-2 Adrenergic Receptors

Alpha-2 adrenergic receptors are located on peripheral nerve endings, where they inhibit the release of norepinephrine when activated. This creates a feedback mechanism that regulates norepinephrine release.[15]

Nonselective Alpha-Adrenergic Antagonists

Nonselective alpha-adrenergic antagonists cause vasodilation by blocking both alpha-1 and alpha-2 receptors. Blocking alpha-2 receptors leads to an increase in norepinephrine release, which can counteract the vasodilation effects of alpha-1 receptor blockade. These medications are most effective when sympathetic activity is elevated, such as during stress or when there is an increase in circulating catecholamines, making them particularly useful for patients with pheochromocytoma.[15][16] They are intended for short-term use only. Please see StatPearls' companion resource, "Perioperative Management of Pheochromocytoma," for more information.

Selective Alpha-Adrenergic Antagonists 

Selective alpha-1 adrenergic antagonists: These antagonists cause vasodilation by blocking norepinephrine from activating the alpha-1 receptor, which lowers blood pressure. While effective for hypertension, they are considered second-line agents due to adverse effects, such as orthostatic hypotension. Alpha-1 blockers also induce smooth muscle relaxation in the prostate and bladder neck, facilitating urine flow in patients with obstructive uropathy due to prostatic enlargement.[10] As a result, these medications are effective for managing the symptoms of BPH.[9][15][17] 

Selective alpha-1 adrenergic antagonists typically work quickly, with symptomatic relief often noted within a few days of starting therapy, making them the preferred agents for the initial treatment of symptomatic BPH. Alpha-blocker therapy may also be used for female patients with urinary retention and other lower urinary tract symptoms.[18]

This class of alpha-blockers has also been shown to increase the spontaneous expulsion rate of ureteral calculi by relaxing ureteral smooth muscle, particularly for distal ureteral stones. As a result, it is now considered first-line therapy for this indication.[19][20][21][22] Of the available alpha-blocker medications, silodosin appears to be the most effective for medical expulsive therapy of ureteral calculi.[23][24][25] An optimal duration of up to 3 weeks has been suggested, after which it should be considered a therapeutic failure.[21][22] Alpha-blockers have also shown efficacy in treating premature ejaculation; however, they may decrease semen volume and inhibit seminal emission.[26] 

Selective alpha-2 adrenergic antagonists: These antagonists inhibit the negative feedback of norepinephrine, thereby stimulating the sympathetic nervous system. However, there is limited evidence on the clinical significance of this mechanism in human medicine.[15]

Administration

Phenoxybenzamine is a long-acting oral medication typically started 10 to 14 days before pheochromocytoma excision. Initial dosing begins at 10 mg twice daily and can be increased every other day, usually reaching 20 to 40 mg 2 or 3 times daily. Please see StatPearls' companion resource, "Phenoxybenzamine," for more information.

Phentolamine is used as an adjunct to control high blood pressure before and during the removal of pheochromocytoma. The typical dose is 5 mg, which can be administered either intramuscularly or intravenously.[27] 

Selective alpha-1 blockers are oral medications typically taken at night to minimize the risk of orthostatic hypotension, which is most pronounced with doxazosin, prazosin, and terazosin. The standard daily dose of tamsulosin is 0.4 mg, which may be increased to a maximum of 0.8 mg if the clinical response is inadequate. Alfuzosin should be taken immediately after a meal and is administered as a single 10 mg daily dose. If further treatment is needed, salvage therapy with a 5-alpha-reductase inhibitor (such as finasteride or dutasteride) may be considered, although these medications generally require 6 months to demonstrate clinical effectiveness. Please see StatPearls' companion resources, "5α-Reductase Inhibitors," "Dutasteride," and "Finasteride," for more information.

Adverse Effects

Nonselective alpha-blockers may cause hypotension, weakness, tachycardia, and tremulousness. Hypotension occurs due to the inhibition of arterial alpha-1 receptors, leading to vascular smooth muscle relaxation and vasodilation. Consequently, alpha-blocker therapy should be used with caution in patients with existing hypotension or a history of orthostatic hypotension. The remaining adverse effects result from the increased release of norepinephrine caused by simultaneous alpha-2 receptor antagonism. This norepinephrine spillover stimulates beta receptors, leading to tremulousness and tachycardia.[28] 

Adverse systemic effects, such as tachycardia and tremulousness, are less common with selective alpha-1 blockers. However, these medications can cause first-dose hypotension, syncope, dizziness, and headache due to vasodilation and vascular smooth muscle relaxation. Reflex tachycardia may occur as a response to a sudden drop in blood pressure. These adverse effects are more common in older patients, increasing their risk of falls. To minimize these risks, it is recommended that patients take the medication at night.[28]

Floppy iris syndrome is an intraoperative complication that can occur during cataract surgery. Although associated with any selective alpha-blocker, it is most commonly associated with tamsulosin use.[29] Long-term administration of alpha-blockers may lead to dysfunction or atrophy of the iris dilator muscle, potentially resulting in permanent damage. This impairment can prevent adequate iris dilation during cataract surgery. Clinical features include iris billowing, prolapse through surgical incisions, and progressive pupillary constriction despite mydriatic therapy.[30][31] These effects significantly elevate the risk of postoperative complications following cataract surgery, with the incidence of floppy iris syndrome reported to range from 33% to 86%.[32]

Contraindications

Alpha-blockers are contraindicated in individuals with known hypersensitivity to these medications or any component of their formulation. Caution is advised when prescribing alpha-blockers to older patients, as they may increase the risk of complications during cataract surgery. These include sudden iris prolapse and pupil constriction—a phenomenon referred to as "intraoperative floppy iris syndrome."[9][33]

Nonselective alpha-adrenergic antagonists have additional contraindications. Phenoxybenzamine and phentolamine are contraindicated in a breastfeeding mother. Clinicians should exercise caution if the patient has marked renal impairment, cerebrovascular disease, coronary artery disease, or a current respiratory infection. These medications are not suitable for long-term use.[28]

Monitoring

Due to the risk of hypotension and tachycardia with phentolamine, the blood pressure and heart rate of patients must be closely monitored when administering phentolamine intraoperatively for pheochromocytoma removal.[34]

For other alpha-adrenergic antagonists, routine monitoring or specific tests are currently not recommended.

Toxicity

Alpha-blockers are frequently prescribed to older male populations, and toxicity is common in these individuals. The most common adverse effect is hypotension, which, when severe, can cause ischemic damage to major organs and increase the risk of falls.

Alpha-blockers may increase the risk of significant hypotension when used in combination with 5-aminolevulinic acid in bladder cancer patients undergoing photodynamic-enhanced cystoscopic diagnosis.[35]

General measures should be taken to optimize blood pressure if toxicity is suspected.[36] If the patient is hypotensive, they should be positioned supine until blood pressure and heart rate stabilize. If hypotension persists, fluid resuscitation may be required. Vasopressors can be administered as a last resort if necessary.[37] No specific antidote is available. 

Enhancing Healthcare Team Outcomes

Preventing medication-related adverse effects in older populations requires careful coordination and communication among physicians, pharmacists, and nurses. Selective alpha-1 antagonists are commonly prescribed for patients with BPH in outpatient settings. These medications can interact significantly with other drugs that share similar adverse effects. Clinical staff must thoroughly review the patient's medical and social history before prescribing or ordering an alpha-blocker. In particular, prescribers should be aware that tamsulosin 0.4 mg represents only half of the full recommended dose of 0.8 mg and should consider adjusting the dosage before concluding it is a therapeutic failure.

If a patient taking an alpha-blocker resides in a nursing facility, close communication with the nursing staff is essential, as the patient is at an increased risk of orthostatic hypotension, which can lead to falls. Fall precautions, such as bed rails, a bed alarm, a bedside commode, nightlights, and a floor protection mat, should be considered. The administration of alpha-blockers requires collaboration among an interprofessional healthcare team, including physicians, pharmacists, and nurses, to prevent adverse effects, particularly in the older population.


Details

Editor:

Jayesh B. Patel

Updated:

2/6/2025 12:36:07 AM

References


[1]

Yu M, Han C, Zhou Q, Liu C, Ding Z. Clinical effects of prophylactic use of phentolamine in patients undergoing pheochromocytoma surgery. Journal of clinical anesthesia. 2018 Feb:44():119. doi: 10.1016/j.jclinane.2017.11.030. Epub 2017 Nov 29     [PubMed PMID: 29195099]


[2]

Sambhunath D, Pankaj K, Usha K. Role of phenoxybenzamine in perioperative clinical practice. Annals of cardiac anaesthesia. 2015 Oct-Dec:18(4):577-8. doi: 10.4103/0971-9784.166473. Epub     [PubMed PMID: 26440247]


[3]

Chan GM, Sharma R, Price D, Hoffman RS, Nelson LS. Phentolamine therapy for cocaine-association acute coronary syndrome (CAACS). Journal of medical toxicology : official journal of the American College of Medical Toxicology. 2006 Sep:2(3):108-11     [PubMed PMID: 18072128]


[4]

Hollander JE, Carter WA, Hoffman RS. Use of phentolamine for cocaine-induced myocardial ischemia. The New England journal of medicine. 1992 Jul 30:327(5):361     [PubMed PMID: 1620184]


[5]

Hollander JE, Henry TD. Evaluation and management of the patient who has cocaine-associated chest pain. Cardiology clinics. 2006 Feb:24(1):103-14     [PubMed PMID: 16326260]


[6]

Duncan C, Omran GJ, Teh J, Davis NF, Bolton DM, Lawrentschuk N. Erectile dysfunction: a global review of intracavernosal injectables. World journal of urology. 2019 Jun:37(6):1007-1014. doi: 10.1007/s00345-019-02727-5. Epub 2019 Mar 20     [PubMed PMID: 30895359]


[7]

Salonia A, Bettocchi C, Boeri L, Capogrosso P, Carvalho J, Cilesiz NC, Cocci A, Corona G, Dimitropoulos K, Gül M, Hatzichristodoulou G, Jones TH, Kadioglu A, Martínez Salamanca JI, Milenkovic U, Modgil V, Russo GI, Serefoglu EC, Tharakan T, Verze P, Minhas S, EAU Working Group on Male Sexual and Reproductive Health. European Association of Urology Guidelines on Sexual and Reproductive Health-2021 Update: Male Sexual Dysfunction. European urology. 2021 Sep:80(3):333-357. doi: 10.1016/j.eururo.2021.06.007. Epub 2021 Jun 26     [PubMed PMID: 34183196]


[8]

Corona G, Cucinotta D, Di Lorenzo G, Ferlin A, Giagulli VA, Gnessi L, Isidori AM, Maiorino MI, Miserendino P, Murrone A, Pivonello R, Rochira V, Sangiorgi GM, Stagno G, Foresta C, Lenzi A, Maggi M, Jannini EA. The Italian Society of Andrology and Sexual Medicine (SIAMS), along with ten other Italian Scientific Societies, guidelines on the diagnosis and management of erectile dysfunction. Journal of endocrinological investigation. 2023 Jun:46(6):1241-1274. doi: 10.1007/s40618-023-02015-5. Epub 2023 Jan 25     [PubMed PMID: 36698034]


[9]

. Alpha 1 Adrenergic Receptor Antagonists. LiverTox: Clinical and Research Information on Drug-Induced Liver Injury. 2012:():     [PubMed PMID: 31644028]


[10]

Koudonas A, Anastasiadis A, Tsiakaras S, Langas G, Savvides E, Mykoniatis I, Memmos D, Baniotis P, Vakalopoulos I, de la Rosette J, Dimitriadis G. Overview of current pharmacotherapeutic options in benign prostatic hyperplasia. Expert opinion on pharmacotherapy. 2023 Sep-Dec:24(14):1609-1622. doi: 10.1080/14656566.2023.2237406. Epub 2023 Jul 21     [PubMed PMID: 37448198]

Level 3 (low-level) evidence

[11]

Cui T, Kovell RC, Brooks DC, Terlecki RP. A Urologist's Guide to Ingredients Found in Top-Selling Nutraceuticals for Men's Sexual Health. The journal of sexual medicine. 2015 Nov:12(11):2105-17. doi: 10.1111/jsm.13013. Epub 2015 Nov 3     [PubMed PMID: 26531010]


[12]

Lepor H. Alpha-blockers for the Treatment of Benign Prostatic Hyperplasia. The Urologic clinics of North America. 2016 Aug:43(3):311-23. doi: 10.1016/j.ucl.2016.04.009. Epub     [PubMed PMID: 27476124]


[13]

Porrill SL, Rogers RR, Ballmann CG. Ergogenic and Sympathomimetic Effects of Yohimbine: A Review. Neurology international. 2024 Dec 12:16(6):1837-1848. doi: 10.3390/neurolint16060131. Epub 2024 Dec 12     [PubMed PMID: 39728757]


[14]

Nowacka A, Śniegocka M, Śniegocki M, Ziółkowska E, Bożiłow D, Smuczyński W. Multifaced Nature of Yohimbine-A Promising Therapeutic Potential or a Risk? International journal of molecular sciences. 2024 Nov 29:25(23):. doi: 10.3390/ijms252312856. Epub 2024 Nov 29     [PubMed PMID: 39684567]


[15]

Nash DT. Alpha-adrenergic blockers: mechanism of action, blood pressure control, and effects of lipoprotein metabolism. Clinical cardiology. 1990 Nov:13(11):764-72     [PubMed PMID: 1980236]


[16]

Criscitelli TM. Caring for Patients With Pheochromocytomas in the Perioperative Setting: Earn 1.4 Contact Hours. AORN journal. 2024 Dec:120(6):363-369. doi: 10.1002/aorn.14248. Epub     [PubMed PMID: 39588999]


[17]

Mantica G, Ambrosini F, Drocchi G, Zubko Z, Lo Monaco L, Cafarelli A, Calarco A, Colombo R, De Cobelli O, De Marco F, Ferrari G, Ludovico G, Pecoraro S, Tuzzolo D, Terrone C, Leonardi R. Non-surgical management of BPH: An updated review of current literature and state of the art on natural compounds and medical therapy. Archivio italiano di urologia, andrologia : organo ufficiale [di] Societa italiana di ecografia urologica e nefrologica. 2024 Dec 18:96(4):13098. doi: 10.4081/aiua.2024.13098. Epub 2024 Dec 18     [PubMed PMID: 39692412]


[18]

Wee CB, Kim TH, Tae JH, Choi SY. Efficacy and Safety of Silodosin for the Treatment of Female LUTS: A 12-Week Prospective, Single-Center Study. Lower urinary tract symptoms. 2025 Jan:17(1):e70005. doi: 10.1111/luts.70005. Epub     [PubMed PMID: 39763466]


[19]

Yan H, Li X, Zheng X, Cui Y, Huang J, Cheng Y. Evaluating the safety and effectiveness of α-blockers versus mirabegron for medical expulsive therapy in ureteral calculi: A Systematic review and meta-analysis. PloS one. 2024:19(12):e0315328. doi: 10.1371/journal.pone.0315328. Epub 2024 Dec 27     [PubMed PMID: 39729463]

Level 1 (high-level) evidence

[20]

Campschroer T, Zhu X, Vernooij RW, Lock MT. Alpha-blockers as medical expulsive therapy for ureteral stones. The Cochrane database of systematic reviews. 2018 Apr 5:4(4):CD008509. doi: 10.1002/14651858.CD008509.pub3. Epub 2018 Apr 5     [PubMed PMID: 29620795]

Level 1 (high-level) evidence

[21]

Raison N, Ahmed K, Brunckhorst O, Dasgupta P. Alpha blockers in the management of ureteric lithiasis: A meta-analysis. International journal of clinical practice. 2017 Jan:71(1):. doi: 10.1111/ijcp.12917. Epub     [PubMed PMID: 28097758]

Level 1 (high-level) evidence

[22]

Erdoğan E, Şimşek G, Aşık A, Yaşar H, Şahin C, Sarıca K. Optimal duration of medical expulsive therapy for lower ureteral stones: a critical evaluation. Urolithiasis. 2024 Mar 23:52(1):48. doi: 10.1007/s00240-024-01548-5. Epub 2024 Mar 23     [PubMed PMID: 38520492]


[23]

Ramadhani MZ, Kloping YP, Rahman IA, Yogiswara N, Soebadi MA, Renaldo J. Silodosin as a medical expulsive therapy for distal ureteral stones: A systematic review and meta-analysis. Indian journal of urology : IJU : journal of the Urological Society of India. 2023 Jan-Mar:39(1):21-26. doi: 10.4103/iju.iju_115_22. Epub 2022 Dec 29     [PubMed PMID: 36824112]

Level 1 (high-level) evidence

[24]

Soliman MG, El-Gamal O, El-Gamal S, Abdel Raheem A, Abou-Ramadan A, El-Abd A. Silodosin versus Tamsulosin as Medical Expulsive Therapy for Children with Lower-Third Ureteric Stones: Prospective Randomized Placebo-Controlled Study. Urologia internationalis. 2021:105(7-8):568-573. doi: 10.1159/000513074. Epub 2021 Feb 1     [PubMed PMID: 33524970]

Level 1 (high-level) evidence

[25]

Jung HD, Cho KS, Jun DY, Jeong JY, Moon YJ, Chung DY, Kang DH, Cho S, Lee JY. Silodosin versus Tamsulosin for Medical Expulsive Therapy of Ureteral Stones: An Updated Systematic Review and Meta-Analysis of Randomized Controlled Trials. Medicina (Kaunas, Lithuania). 2022 Dec 6:58(12):. doi: 10.3390/medicina58121794. Epub 2022 Dec 6     [PubMed PMID: 36556996]

Level 1 (high-level) evidence

[26]

Fauzan MI, Daryanto B, Budaya TN, Makkaraka MAG, Fakhri M, Rahman IA. Promising selective alpha-1 blocker silodosin as a new therapeutic strategy for premature ejaculation and analysis of its drug adverse effect: A systematic review and meta-analysis of randomized controlled trials. Archivio italiano di urologia, andrologia : organo ufficiale [di] Societa italiana di ecografia urologica e nefrologica. 2024 Nov 11:96(4):12984. doi: 10.4081/aiua.2024.12984. Epub 2024 Nov 11     [PubMed PMID: 39692416]

Level 1 (high-level) evidence

[27]

Naranjo J, Dodd S, Martin YN. Perioperative Management of Pheochromocytoma. Journal of cardiothoracic and vascular anesthesia. 2017 Aug:31(4):1427-1439. doi: 10.1053/j.jvca.2017.02.023. Epub 2017 Feb 4     [PubMed PMID: 28392094]


[28]

Frishman WH, Kotob F. Alpha-adrenergic blocking drugs in clinical medicine. Journal of clinical pharmacology. 1999 Jan:39(1):7-16     [PubMed PMID: 9987696]


[29]

Kaushik J, Sharma R, Goyal S, Dangi M, Jha RK, Singh A. Alpha-adrenergic antagonists and iris dynamics: Challenges and solutions in cataract surgery. BMC ophthalmology. 2024 Oct 3:24(1):431. doi: 10.1186/s12886-024-03705-1. Epub 2024 Oct 3     [PubMed PMID: 39363270]


[30]

Bumbuluț B, Stănilă DM. Floppy iris. How is floppy iris syndrome managed? What do urologists and ophthalmologists say? Romanian journal of ophthalmology. 2024 Jul-Sep:68(3):301-305. doi: 10.22336/rjo.2024.54. Epub     [PubMed PMID: 39464767]


[31]

Yang X, Liu Z, Fan Z, Grzybowski A, Wang N. A narrative review of intraoperative floppy iris syndrome: an update 2020. Annals of translational medicine. 2020 Nov:8(22):1546. doi: 10.21037/atm-20-3214. Epub     [PubMed PMID: 33313291]

Level 3 (low-level) evidence

[32]

Chang DF. Floppy iris syndrome: why BPH treatment can complicate cataract surgery. American family physician. 2009 Jun 15:79(12):1051, 1055-6     [PubMed PMID: 19530635]


[33]

Christou CD, Tsinopoulos I, Ziakas N, Tzamalis A. Intraoperative Floppy Iris Syndrome: Updated Perspectives. Clinical ophthalmology (Auckland, N.Z.). 2020:14():463-471. doi: 10.2147/OPTH.S221094. Epub 2020 Feb 20     [PubMed PMID: 32109982]

Level 3 (low-level) evidence

[34]

McMillian WD, Trombley BJ, Charash WE, Christian RC. Phentolamine continuous infusion in a patient with pheochromocytoma. American journal of health-system pharmacy : AJHP : official journal of the American Society of Health-System Pharmacists. 2011 Jan 15:68(2):130-4. doi: 10.2146/ajhp090619. Epub     [PubMed PMID: 21200059]


[35]

Suzuki C, Minagawa T, Onuma H, Hiragata S, Kinebuchi Y. α(1)-Blockers as a risk factor for hypotension in combination with oral 5-aminolevulimic acid for photodynamic diagnosis in patients with bladder cancer. International journal of urology : official journal of the Japanese Urological Association. 2025 Jan 3:():. doi: 10.1111/iju.15655. Epub 2025 Jan 3     [PubMed PMID: 39749845]


[36]

Ramirez J. Severe hypotension associated with α blocker tamsulosin. BMJ (Clinical research ed.). 2013 Nov 5:347():f6492. doi: 10.1136/bmj.f6492. Epub 2013 Nov 5     [PubMed PMID: 24192968]


[37]

Arnold AC, Raj SR. Orthostatic Hypotension: A Practical Approach to Investigation and Management. The Canadian journal of cardiology. 2017 Dec:33(12):1725-1728. doi: 10.1016/j.cjca.2017.05.007. Epub 2017 May 17     [PubMed PMID: 28807522]