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Alpha-Adrenergic Receptors

Editor: Manouchkathe Cassagnol Updated: 7/10/2023 2:09:45 PM


The indication for the use of an alpha-adrenergic receptor modifying medication depends on which receptor is the target: the alpha-1 receptor or the alpha-2 receptor. Alpha-1 receptors bind catecholamines including, both epinephrine and norepinephrine. In instances in which there is hypoperfusion secondary to decreased cardiac output or decreased systemic vasculature resistance, alpha-1 receptors become stimulated.  It is worth noting that these compounds are not purely selective for the alpha receptor, and often engage beta-adrenergic receptors as well. The use of alpha-1 agonists is common in all types of shock, cardiopulmonary resuscitation, and heart failure decompensation.[1]  Alpha-1 agonists, such as phenylephrine, are also used to treat upper airway congestion as stimulating the receptor leads to a decreased mucus secretion.[2] Alpha-antagonists, colloquially known as alpha-blockers, work in the peripheral vasculature and inhibit the uptake of catecholamines in smooth muscle cells resulting in vasodilation and blood pressure lowering. Alpha-antagonists, including doxazosin, prazosin, and phentolamine - are primarily used in the treatment of hypertension and urinary retention.[3] 

Alpha-blockers have significant use in the setting of pre-operative pheochromocytoma care.[4] Alpha-blockers are also used off-label for the treatment of post-traumatic stress disorder (PTSD).[5] Alpha-2 stimulation reduces the sympathetic outflow from the vasomotor center centrally and increases vagal tone. Peripheral presynaptic alpha-2 receptors may also reduce sympathetic tone. Alpha-2 agonists, including clonidine and guanfacine - are used as anti-hypertensives, as well.[6]  Both clonidine and guanfacine are used for behavior modification in children with attention deficit disorder, as well as in adults with PTSD as well.[7][8] 

Alpha-1 Agonists

FDA Approved Indications

Oral Agents

  • Midodrine
    • Treatment of symptomatic orthostatic hypotension

Topical Agents

  • Naphazoline/naphazoline-pheniramine
    • Topical ocular vasoconstriction
    • Use for the relief of redness in the eye/itching (pheniramine)
  • Phenylephrine
    • Dilate pupils (ophthalmic)
    • Temporary relief of nasal congestion due to the common cold or allergic rhinitis (nasal)
    • Used in the treatment of hemorrhoids (rectal/topical)
  • Xylometazoline
    • Temporary relief of nasal and nasopharyngeal mucosal congestion


  • Phenylephrine
    • Hypotension/shock/cardiogenic shock
    • Hypotension during anesthesia: vasoconstrictor in regional analgesia

Off-label Uses

Oral Agents

  • Midodrine
    • Refractory ascites[9]
    • Prevention of dialysis-induced hypotension
    • Hepatorenal syndrome
    • Vasovagal syndrome

Topical Agents

  • Phenylephrine
    • Topical vasoconstriction in nasal procedures


  • Phenylephrine
    • Hypotension in patients with obstructive hypertrophic cardiomyopathy
    • Priapism

Alpha-1 Blockers

FDA Approved Indications

Oral Agents

  • Treatment for signs and symptoms of benign prostatic hyperplasia (BPH)[10]
    • Alfuzosin
    • Tamsulosin
    • Doxazosin
    • Terazosin
    • Silodosin
  • Management of hypertension; alpha-blockers not recommended as the first-line agents[11]
    • Prazosin
    • Doxazosin
    • Terazosin

Intravenous Agents

  • Phentolamine
    • Pheochromocytoma: Diagnosis of this condition via the phentolamine blocking test
    • Extravasation management: prevention of dermal necrosis/sloughing after extravasation of norepinephrine
    • Local anesthesia reversal: reversal of soft tissue anesthesia and the associated functional deficits resulting from intraoral submucosal injections of local anesthetics
  • Phenoxybenzamine
    • Pheochromocytoma: Treatment of sweating and hypertension associated with the condition

Off-label Uses

Specific Agents

  • Tamsulosin:
    • Chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) in males
    • Lower urinary tract symptoms (LUTS) in males
    • Ureteral calculi expulsion
    • Ureteral stent-related urinary symptoms, treatment
  • Prazosin
    • Post-traumatic stress disorder PTSD related nightmares and sleep disruptions[12]
    • Raynaud phenomenon
  • Phentolamine
    • Hypertensive crisis
    • Extravasation of sympathomimetic vasopressors
  • Phenoxybenzamine
    • Hypertensive crisis caused by sympathomimetic amines
    • Micturition problems associated with neurogenic bladder
    • Functional outlet obstruction and partial prostate obstruction

Other Uses

  • Ureteral calculi (distal)[13]
    • Alfuzosin
    • Doxazosin
    • Terazosin
    • Silodosin

Alpha-2 Agonists

FDA Approved Indications


  • Clonidine
    • Treatment of attention-deficit/hyperactivity disorder (ADHD) as monotherapy or as adjunctive therapy (extended-release tablet)[14]
    • Management of hypertension, but not recommended as first-line treatment, should be avoided in heart failure patients with a reduced ejection fraction of ischemic origin[11][15]
  • Guanfacine
    • Treatment of attention-deficit/hyperactivity disorder (ADHD) as monotherapy or as adjunctive therapy (extended-release tablet)[14]
    • Management of hypertension, not recommended first line, (immediate-release)[11]
  • Methyldopa
    • Management of hypertension, not recommended first line, particular use in pregnancy; may cause positive Coombs test[11]
  • Lofexidine
    • Mitigation of opioid withdrawal symptoms to facilitate abrupt opioid discontinuation in adults[16]
  • Tizanidine
    • Management of spasticity; reserve treatment with tizanidine for daily activities and times when relief of spasticity is most improtant[17]


  • Brimonidine
    • Topical treatment of persistent (non-transient) erythema of rosacea in adults


  • Clonidine
    • Continuous epidural administration as adjunctive therapy with opioids for the treatment of severe cancer pain in patients tolerant to or unresponsive to opioids alone; more effective for neuropathic pain and less effective (or possibly ineffective) for somatic or visceral pain[18] (epidural)
  • Dexmedetomidine
    • Intensive care unit sedation: Sedation of initially intubated and mechanically ventilated patients during treatment in intensive care settings
    • Procedural sedation: Procedural sedation before and/or during awake fiberoptic intubation; sedation before and/or during surgical or other procedures of non-intubated patients

Off-label Uses

  • Clonidine
    • Clozapine-induced sialorrhea
    • Diagnosis of pheochromocytoma
    • Growth hormone stimulation test
    • Opioid withdrawal
    • Tourette syndrome
    • Vasomotor symptoms associated with menopause
  • Dexmedetomidine
    • Sedation during awake craniotomy
    • Treatment of shivering

Mechanism of Action

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Mechanism of Action

There are two types of alpha-adrenergic receptors; alpha-1 and alpha-2. Both are G-protein coupled receptors (GPCR); however, the downstream effects of the two are different. The alpha-1 receptor is of the Gq type, resulting in activation of phospholipase C, increasing IP3 and DAG, and ultimately increasing the intracellular calcium concentrations leading to smooth muscle contraction and glycogenolysis.[19] The alpha-2 receptor acts as an allosteric inhibitor through Gi function, leading to an inhibition of adenylyl cyclase, decreasing the formation of intracellular cAMP.  It also leads to a reduced amount of cytoplasmic calcium, which decreases neurotransmitter release and central vasodilation.[20] Epinephrine and norepinephrine have relatively equal affinities for both types of alpha-receptors, with other drugs used in shock having a higher selectivity for the alpha-1 receptor.  


Administration of alpha-1 receptor agonists is done intravenously through a central line for shock. In the setting of anaphylaxis, epinephrine administration should be either intramuscular or subcutaneous, not intravenous. Phenylephrine can be administered orally for congestion. Alpha-1 receptor antagonists can be administered orally for refractory hypertension, behavioral modification, and urinary hesitancy.  In the emergent setting, the administration of alpha-1 blockade agents can be via the intravenous route. Alpha-1 antagonists are predominantly administered orally and in the outpatient setting. Alpha-2 agonists can be given orally or intravenously, depending on the setting and requirement.  

Adverse Effects

The adverse effects can be related to autonomic response to the systemic changes induced by the agent or to other receptors being antagonized, often those in the beta-adrenergic receptor family.  When ordering an alpha-1 blocker, it is important to be aware and inform the patient of a first-dose effect. With the initial administration of an alpha-1 blocker, systemic vasodilation can lead to a tachycardic response and orthostatic hypotension.[21] This same effect may also occur in the alpha-2 agonist family; however, this is generally less pronounced than in the alpha-1 blockade. The most common adverse effects of alpha-2 receptor agonists are sedation and fatigue.[22] The adverse effects of alpha-1 agonists include hypertension, tachycardia or other dysrhythmias, increased cardiac demand, and subcutaneous ischemia at the site of injection.[23][24]


As with all drugs, the prescriber should account for any previous history of hypersensitivity before the administration. Alpha-1 receptor agonists are contraindicated in patients with the Reynaud phenomenon or closed-angle glaucoma.[25] Epinephrine should not be given subcutaneously in the upper or lower digits, nose, or penis.[26] Alpha-1 agonists given for congestion are contraindicated in the setting of hypertension, tachycardia, or any cardiac history, causing increased demand on the heart. If prescribing an alpha-1 receptor agonist for vasoconstriction, the administration must be through a central line. The main contraindications for the use of an alpha-blocking agent are a history of orthostatic hypotension and concurrent use of phosphodiesterase inhibitors.[27] Contraindications for alpha-2 agonists include concurrent use of phosphodiesterase inhibitors, orthostatic hypotension, and any condition leading to autonomic instability.[28] 


Monitoring depends on the setting of drug administration. If the clinician is giving the drug to increase systemic vascular resistance, then the patient should be maintained on continuous telemetry with ideally continuous monitoring of central venous pressure and arterial pressure. During a period of acute illness, the patient and will likely be under close monitoring in general; special consideration is necessary for cardiac rhythm and blood pressure.  If being given for anaphylaxis, the patient should be monitored in a hospital setting for at least ten hours, as anaphylaxis can have a biphasic onset related to the metabolism of the epinephrine.[29] Patients receiving alpha-1 agonists require monitoring for tachyarrhythmias, blood pressure, and other adverse symptoms relative to taking the drug. In patients receiving either alpha-1 blocking agents or alpha-2 agonists, blood pressure and orthostatic hypotension warrant specific attention.  


Alpha-1 receptor agonists taken at toxic doses lead to increased sympathetic tone, which results in tachycardia, early hypertension progressing to hypotension, mydriasis, anxiety, and increased glycogenolysis. Recent ingestion or asymptomatic patients require observation; if very recent, then activated charcoal may be an option to attempt to prevent the drug from absorbing if the drug was ingested orally. If symptomatic, the patient should be admitted, generally to the intensive care unit. Symptomatic treatment is the mainstay, with control of the airway, blood pressure, and heart rate. The alpha blockade may be attempted with caution, as well. Once symptoms abate, the patient is considered to have wholly metabolized the drug. The toxicity of alpha-1 blockers and alpha-2 agonists is an unopposed parasympathetic activity, with bradycardia, hypotension, miosis, and sedation. Observation is sufficient in asymptomatic patients. Supportive care is necessary for symptomatic patients. There is no single antidote for either type of toxicities.[6]

Enhancing Healthcare Team Outcomes

Alpha-1 agonists are used in the critical care setting to increase systemic vascular resistance are considered high alert drugs and can be very dangerous if used or dosed incorrectly. Clear and concise communication is necessary between the nurse, pharmacist, and ordering practitioner (physician, nurse, or physician assistant) in these instances to prevent mistakes that can cause morbidity and mortality. Very close continuous monitoring is also necessary for patients receiving these drugs, and many facilities assign these patients a one-to-one nurse staffing. Many local anesthetics are co-formulated with epinephrine as a hemostatic agent, and when injected subcutaneously, this can cause skin necrosis. Special care between physicians, pharmacists, and nurses is necessary to identify the local agents containing epinephrine clearly to prevent unnecessary complications. Many alpha-1 and alpha-2 drugs are used clinically in the emergency department, so clinical staff must be very thorough in medical and social history before ordering these medications.  In patients that are in skilled nursing facilities that are likely fall risks, if given an alpha-1 blocker or alpha-2 agonist, it should be communicated that they should have close monitoring by nursing staff, as well as fall precautions including a bed alarm, bed rails, and a fall mat, due to the risk of orthostatic hypotension. Drugs that affect alpha-receptors, both antagonists and agonists, require an interprofessional team approach to include clinicians, specialists, nurses, and pharmacists, all working as a collaborative interprofessional team, to direct therapy optimally and derive successful results for patients. [Level V]



Sacha GL, Bauer SR, Lat I. Vasoactive Agent Use in Septic Shock: Beyond First-Line Recommendations. Pharmacotherapy. 2019 Mar:39(3):369-381. doi: 10.1002/phar.2220. Epub 2019 Feb 7     [PubMed PMID: 30644586]


Weinberger M, Hendeles L. Nonprescription medications for respiratory symptoms: Facts and marketing fictions. Allergy and asthma proceedings. 2018 May 1:39(3):169-176. doi: 10.2500/aap.2018.39.4117. Epub     [PubMed PMID: 29669663]


de Araújo LJT, Nagaoka MR, Borges DR, Kouyoumdjian M. Participation of hepatic α/β-adrenoceptors and AT1 receptors in glucose release and portal hypertensive response induced by adrenaline or angiotensin II. Brazilian journal of medical and biological research = Revista brasileira de pesquisas medicas e biologicas. 2018 Nov 14:51(12):e7526. doi: 10.1590/1414-431X20187526. Epub 2018 Nov 14     [PubMed PMID: 30462770]


Santos JRU, Wolf KI, Pacak K. A NECESSITY, NOT A SECOND THOUGHT: PRE-OPERATIVE ALPHA-ADRENOCEPTOR BLOCKADE IN PHEOCHROMOCYTOMA PATIENTS. Endocrine practice : official journal of the American College of Endocrinology and the American Association of Clinical Endocrinologists. 2019 Feb:25(2):200-201. doi: 10.4158/1934-2403-25.2.200. Epub     [PubMed PMID: 30817195]


Back SE, Flanagan JC, Jones JL, Augur I, Peterson AL, Young-McCaughan S, Shirley DW, Henschel A, Joseph JE, Litz BT, Hancock AK, Roache JD, Mintz J, Wachen JS, Keane TM, Brady KT, Consortium to Alleviate PTSD. Doxazosin for the treatment of co-occurring PTSD and alcohol use disorder: Design and methodology of a randomized controlled trial in military veterans. Contemporary clinical trials. 2018 Oct:73():8-15. doi: 10.1016/j.cct.2018.08.009. Epub 2018 Aug 24     [PubMed PMID: 30145268]

Level 1 (high-level) evidence


Viera AJ. Hypertension Update: Resistant Hypertension. FP essentials. 2018 Jun:469():20-25     [PubMed PMID: 29863319]


Detweiler MB, Pagadala B, Candelario J, Boyle JS, Detweiler JG, Lutgens BW. Treatment of Post-Traumatic Stress Disorder Nightmares at a Veterans Affairs Medical Center. Journal of clinical medicine. 2016 Dec 16:5(12):. doi: 10.3390/jcm5120117. Epub 2016 Dec 16     [PubMed PMID: 27999253]


Jain R, Katic A. Current and Investigational Medication Delivery Systems for Treating Attention-Deficit/Hyperactivity Disorder. The primary care companion for CNS disorders. 2016 Aug 18:18(4):. doi: 10.4088/PCC.16r01979. Epub 2016 Aug 18     [PubMed PMID: 27828696]


Runyon BA, AASLD. Introduction to the revised American Association for the Study of Liver Diseases Practice Guideline management of adult patients with ascites due to cirrhosis 2012. Hepatology (Baltimore, Md.). 2013 Apr:57(4):1651-3. doi: 10.1002/hep.26359. Epub     [PubMed PMID: 23463403]

Level 1 (high-level) evidence


Strope SA, Elliott SP, Saigal CS, Smith A, Wilt TJ, Wei JT, Urologic Diseases in America Project. Urologist compliance with AUA best practice guidelines for benign prostatic hyperplasia in Medicare population. Urology. 2011 Jul:78(1):3-9. doi: 10.1016/j.urology.2010.12.087. Epub 2011 May 23     [PubMed PMID: 21601254]

Level 1 (high-level) evidence


Whelton PK, Carey RM, Aronow WS, Casey DE Jr, Collins KJ, Dennison Himmelfarb C, DePalma SM, Gidding S, Jamerson KA, Jones DW, MacLaughlin EJ, Muntner P, Ovbiagele B, Smith SC Jr, Spencer CC, Stafford RS, Taler SJ, Thomas RJ, Williams KA Sr, Williamson JD, Wright JT Jr. 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA Guideline for the Prevention, Detection, Evaluation, and Management of High Blood Pressure in Adults: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. Journal of the American College of Cardiology. 2018 May 15:71(19):e127-e248. doi: 10.1016/j.jacc.2017.11.006. Epub 2017 Nov 13     [PubMed PMID: 29146535]

Level 3 (low-level) evidence


Ursano RJ, Bell C, Eth S, Friedman M, Norwood A, Pfefferbaum B, Pynoos JD, Zatzick DF, Benedek DM, McIntyre JS, Charles SC, Altshuler K, Cook I, Cross CD, Mellman L, Moench LA, Norquist G, Twemlow SW, Woods S, Yager J, Work Group on ASD and PTSD, Steering Committee on Practice Guidelines. Practice guideline for the treatment of patients with acute stress disorder and posttraumatic stress disorder. The American journal of psychiatry. 2004 Nov:161(11 Suppl):3-31     [PubMed PMID: 15617511]

Level 1 (high-level) evidence


Preminger GM, Tiselius HG, Assimos DG, Alken P, Buck C, Gallucci M, Knoll T, Lingeman JE, Nakada SY, Pearle MS, Sarica K, Türk C, Wolf JS Jr, EAU/AUA Nephrolithiasis Guideline Panel. 2007 guideline for the management of ureteral calculi. The Journal of urology. 2007 Dec:178(6):2418-34     [PubMed PMID: 17993340]


Subcommittee on Attention-Deficit/Hyperactivity Disorder, Steering Committee on Quality Improvement and Management, Wolraich M, Brown L, Brown RT, DuPaul G, Earls M, Feldman HM, Ganiats TG, Kaplanek B, Meyer B, Perrin J, Pierce K, Reiff M, Stein MT, Visser S. ADHD: clinical practice guideline for the diagnosis, evaluation, and treatment of attention-deficit/hyperactivity disorder in children and adolescents. Pediatrics. 2011 Nov:128(5):1007-22. doi: 10.1542/peds.2011-2654. Epub 2011 Oct 16     [PubMed PMID: 22003063]

Level 1 (high-level) evidence


Rosendorff C, Lackland DT, Allison M, Aronow WS, Black HR, Blumenthal RS, Cannon CP, de Lemos JA, Elliott WJ, Findeiss L, Gersh BJ, Gore JM, Levy D, Long JB, O'Connor CM, O'Gara PT, Ogedegbe O, Oparil S, White WB, American Heart Association, American College of Cardiology, and American Society of Hypertension. Treatment of hypertension in patients with coronary artery disease: A scientific statement from the American Heart Association, American College of Cardiology, and American Society of Hypertension. Journal of the American Society of Hypertension : JASH. 2015 Jun:9(6):453-98. doi: 10.1016/j.jash.2015.03.002. Epub 2015 Mar 31     [PubMed PMID: 25840695]


Lingford-Hughes AR, Welch S, Peters L, Nutt DJ, British Association for Psychopharmacology, Expert Reviewers Group. BAP updated guidelines: evidence-based guidelines for the pharmacological management of substance abuse, harmful use, addiction and comorbidity: recommendations from BAP. Journal of psychopharmacology (Oxford, England). 2012 Jul:26(7):899-952. doi: 10.1177/0269881112444324. Epub 2012 May 23     [PubMed PMID: 22628390]

Level 1 (high-level) evidence


Quality Standards Subcommittee of the American Academy of Neurology and the Practice Committee of the Child Neurology Society, Delgado MR, Hirtz D, Aisen M, Ashwal S, Fehlings DL, McLaughlin J, Morrison LA, Shrader MW, Tilton A, Vargus-Adams J. Practice parameter: pharmacologic treatment of spasticity in children and adolescents with cerebral palsy (an evidence-based review): report of the Quality Standards Subcommittee of the American Academy of Neurology and the Practice Committee of the Child Neurology Society. Neurology. 2010 Jan 26:74(4):336-43. doi: 10.1212/WNL.0b013e3181cbcd2f. Epub     [PubMed PMID: 20101040]

Level 2 (mid-level) evidence


Lundblad M, Trifa M, Kaabachi O, Ben Khalifa S, Fekih Hassen A, Engelhardt T, Eksborg S, Lönnqvist PA. Alpha-2 adrenoceptor agonists as adjuncts to peripheral nerve blocks in children: a meta-analysis. Paediatric anaesthesia. 2016 Mar:26(3):232-8. doi: 10.1111/pan.12825. Epub 2015 Dec 16     [PubMed PMID: 26671834]

Level 1 (high-level) evidence


Biazi GR,Frasson IG,Miksza DR,de Morais H,de Fatima Silva F,Bertolini GL,de Souza HM, Decreased hepatic response to glucagon, adrenergic agonists, and cAMP in glycogenolysis, gluconeogenesis, and glycolysis in tumor-bearing rats. Journal of cellular biochemistry. 2018 Sep;     [PubMed PMID: 29761924]


Durkee CA, Covelo A, Lines J, Kofuji P, Aguilar J, Araque A. G(i/o) protein-coupled receptors inhibit neurons but activate astrocytes and stimulate gliotransmission. Glia. 2019 Jun:67(6):1076-1093. doi: 10.1002/glia.23589. Epub 2019 Feb 23     [PubMed PMID: 30801845]


Kaplan SA, Lee JY, Meehan AG, Kusek JW. Time Course of Incident Adverse Experiences Associated with Doxazosin, Finasteride and Combination Therapy in Men with Benign Prostatic Hyperplasia: The MTOPS Trial. The Journal of urology. 2016 Jun:195(6):1825-9. doi: 10.1016/j.juro.2015.11.065. Epub 2015 Dec 8     [PubMed PMID: 26678956]


Vasseur B, Dufour A, Houdas L, Goodwin H, Harries K, Emul NY, Hutchings S. Comparison of the Systemic and Local Pharmacokinetics of Clonidine Mucoadhesive Buccal Tablets with Reference Clonidine Oral Tablets in Healthy Volunteers: An Open-Label Randomised Cross-Over Trial. Advances in therapy. 2017 Aug:34(8):2022-2032. doi: 10.1007/s12325-017-0585-9. Epub 2017 Jul 19     [PubMed PMID: 28726169]

Level 3 (low-level) evidence


Nawrocki PS,Poremba M,Lawner BJ, Push dose epinephrine use in the management of hypotension during critical care transport. Prehospital emergency care : official journal of the National Association of EMS Physicians and the National Association of State EMS Directors. 2019 Feb 26;     [PubMed PMID: 30808241]


Han JW, Nah SK, Lee SY, Kim CY, Yoon JS, Jang SY. A Prospective, Comparative Study of the Pain of Local Anesthesia Using 2% Lidocaine, 2% Lidocaine With Epinephrine, and 2% Lidocaine With Epinephrine-Bupivicaine Mixture for Eyelid Surgery. Ophthalmic plastic and reconstructive surgery. 2017 Mar/Apr:33(2):132-135. doi: 10.1097/IOP.0000000000000675. Epub     [PubMed PMID: 26974418]

Level 2 (mid-level) evidence


Aydın A, Tugcu G. Toxicological assessment of epinephrine and norepinephrine by analog approach. Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association. 2018 Aug:118():726-732. doi: 10.1016/j.fct.2018.06.028. Epub 2018 Jun 18     [PubMed PMID: 29913233]


Fritz T, Pohlemann T, Klein M. Accidental Thumb Injection With an Epinephrine Autoinjector. Deutsches Arzteblatt international. 2017 Nov 24:114(47):804. doi: 10.3238/arztebl.2017.0804. Epub     [PubMed PMID: 29229045]


Paśko P, Rodacki T, Domagała-Rodacka R, Owczarek D. Interactions between medications employed in treating benign prostatic hyperplasia and food - A short review. Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie. 2016 Oct:83():1141-1145. doi: 10.1016/j.biopha.2016.08.021. Epub 2016 Aug 20     [PubMed PMID: 27551761]


Norman K, Nappe TM. Alpha Receptor Agonist Toxicity. StatPearls. 2023 Jan:():     [PubMed PMID: 29763199]


Kim TH, Yoon SH, Hong H, Kang HR, Cho SH, Lee SY. Duration of Observation for Detecting a Biphasic Reaction in Anaphylaxis: A Meta-Analysis. International archives of allergy and immunology. 2019:179(1):31-36. doi: 10.1159/000496092. Epub 2019 Feb 14     [PubMed PMID: 30763927]

Level 1 (high-level) evidence