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Mohs Micrographic Surgery Anticoagulants And Hemostatic Agents Impact

Editor: Jeremy Davis Updated: 10/14/2023 10:18:13 PM

Introduction

Mohs micrographic surgery (MMS) is a specialized dermatological surgical technique frequently employed when treating non-melanoma skin cancers. MMS is considered a safe surgical procedure with a low overall risk of perioperative complications.[1] A minor amount of intraoperative bleeding is expected during MMS; such bleeding is easily controlled with a combination of electrocautery, gentle mechanical pressure, or topical hemostatic agents. However, rare occurrences of more severe perioperative bleeding may lead to hematoma formation, wound dehiscence, and potential loss of grafts or flaps.

Patients undergoing MMS during the concomitant use of antiplatelet or anticoagulant therapy are at increased risk of perioperative bleeding and subsequent complications.[1][2] Direct-acting oral agent (DOAC) anticoagulant therapy is increasing in frequency and may pose additional perioperative bleeding risks.[3] 

A comprehensive understanding of the risks associated with antiplatelet and anticoagulant medications, partnered with diligent perioperative management and meticulous attention to intraoperative hemostasis, is necessary to reduce complications in patients undergoing MMS during concomitant anticoagulation therapy. This activity will review the current recommendations for the perioperative management of these patients, including the risks, benefits, and technical considerations.

Issues of Concern

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Issues of Concern

Patients undergoing MMS commonly have medical comorbidities with the potential to impact surgical outcomes. Of particular interest is the widespread utilization of antiplatelet and anticoagulant therapies that may increase the frequency of bleeding-related complications. An estimated 25% to 38% of patients undergoing dermatologic surgery are on at least one anticoagulant or antiplatelet agent during the perioperative period.[4] While the consensus is that anticoagulation therapies are safe to continue during the perioperative period, the MMS practitioner must be aware of their use and understand the associated surgical risks.[5]

Many studies have investigated the impact of commonly used antithrombotic agents on the risk of hemorrhagic complications in MMS.[6] The risks of perioperative bleeding-related complications vary with specific drug classes and combination therapies.

Antiplatelet Medications

Antiplatelet agents are a class of pharmaceuticals that inhibit or decrease platelet aggregation, thereby increasing bleeding time. Aspirin and clopidogrel are among the most common antiplatelet agents prescribed to patients commonly undergoing MMS.[3][7] Studies have consistently demonstrated that aspirin monotherapy does not increase the risk of postoperative bleeding and is not associated with a significant increase in hemorrhagic complications in patients undergoing cutaneous surgery, including MMS.[8][9] The impact of clopidogrel monotherapy on bleeding risks is less conclusive; studies indicate either no increased or a mildly increased risk of perioperative complications in dermatologic surgery compared to patients not taking antiplatelet and anticoagulant medications.[10][7][11][12][13] 

However, when clopidogrel and aspirin are combined with other agents, there appears to be a synergistic effect on the risk of bleeding-associated complications. A study revealed that multidrug anticoagulation regimens containing clopidogrel conferred significantly increased risks of bleeding-related complications compared to patients on no anticoagulation or aspirin monotherapy.[11] The same analysis revealed significantly increased complications in patients on dual antiplatelet therapy with clopidogrel and aspirin compared to patients on aspirin monotherapy. Other studies corroborate this increased risk from multidrug anticoagulation regimens.[7][14]

Anticoagulant Medications

Oral anticoagulants that directly target the coagulation cascade rather than platelet formation are also of concern. Warfarin is a well-established vitamin K antagonist and remains a commonly prescribed anticoagulant in patients undergoing MMS.[3] A recent meta-analysis revealed that patients undergoing MMS or excisional treatment of skin cancers were 7 times more likely to have bleeding-related complications than patients not taking anticoagulant therapy.[15] A study by Nast et al revealed a significant increase in minor and moderate bleeding in patients taking warfarin compared to controls.[8] However, some studies indicate that warfarin monotherapy is not associated with an increased risk of surgical complications.[16] 

While the data may be conflicting, there appears to be a slight increase in bleeding complications associated with warfarin in patients undergoing minor cutaneous surgery.[13][17] This risk increases further when warfarin is combined with antiplatelet agents such as clopidogrel.[7][11][18] While an international normalized ratio (INR) may be obtained before surgery to assess the degree of anticoagulation in a patient undergoing cutaneous surgery while on warfarin monotherapy, several studies have shown no clear difference in bleeding complications based on preoperative INR value.[13] 

DOACs such asapixaban, rivaroxaban, and dabigatran are more effective in treating various cardiovascular conditions than traditional anticoagulants, and their use has increased accordingly.[3] Although the available data regarding hemorrhagic complications during concomitant use of these agents is limited, recent studies have demonstrated these agents may pose an even greater risk of hemorrhagic complications than previously studied agents. Anita et al showed a bleeding complication rate of 1.3% in patients on DOACs undergoing MMS compared to a rate of 0.7% for all other patients, although this difference was not significant.[19] A subsequent study revealed that hemorrhagic complications in patients taking DOACs were 7 times more likely compared to other anticoagulant classes.[18]

Clinical Significance

Despite the increased risk of perioperative bleeding-related complications in patients undergoing MMS during concomitant anticoagulation therapy, the current recommendation is for patients to continue these agents during the perioperative period.[5] Discontinuation of clinically indicated anticoagulant or antiplatelet therapy is not without risk, and even brief interruptions in therapy may lead to catastrophic thrombotic events, the risk of which generally outweighs the increase in hemorrhagic complications of dermatologic surgery.[20][21] Adverse effects related to antiplatelet or anticoagulant therapy are often minor and easily managed.[4][22] While there is a relative increase in the risk of hemorrhagic complications attributable to antiplatelet or anticoagulant therapy, the absolute increase of these complications appears minimal, even for multidrug therapeutic regimens.[7]

Given the current evidence, withholding antiplatelet and anticoagulant agents, including DOACS, before MMS is not routinely recommended.[18] Aspirin taken for analgesia instead of antiplatelet activity may be safely held in the perioperative period. Obtaining an INR for patients on warfarin is neither required nor common practice; if a preoperative INR indicates supratherapeutic treatment, consultation with the prescribing provider or postponing the MMS procedure is warranted.[23]

Other Issues

Mitigating the risks of hemorrhagic complications in the anticoagulated patient undergoing cutaneous surgery requires meticulous attention to intraoperative technique and hemostasis.[24] Optimal intraoperative hemostasis provides several surgical benefits, including improved visualization of the surgical field, enhanced technical precision, reduced procedure time, and risk reduction.[25][26] Achieving intraoperative hemostasis is especially important in the anticoagulated patient; several hemostatic modalities may be employed.[26] Electrosurgery is the most effective and commonly used method of achieving hemostasis in dermatologic surgery due to its ease of use, availability, and efficiency.[27] Hemostatic agents are also commonly utilized to achieve hemostasis in most dermatologic procedures and can be used as monotherapy or as part of a multimodal approach. Postoperative pressure dressings can be applied to assist with hemostasis as appropriate.[24][28]

While hemostatic agents can benefit hemostasis in anticoagulated patients, no single agent suits every clinical circumstance. Topical hemostatic agents used in cutaneous surgery include caustic, noncaustic, and physiologic agents, each with a different mechanism of action.

Caustic Agents

Applying topical caustic hemostatic agents induces hemostasis by inducing tissue necrosis and protein coagulation, leading to thrombus formation in the exposed cutaneous vessels.[29] Topical caustic hemostatic agents include ferric subsulfate, aluminum chloride, and zinc paste, commonly used in superficial wounds created by shave or punch biopsies. Aluminum chloride is the most frequently used agent in this class due to its low cost, widespread availability, and minimal adverse effect profile characterized by mild pain and tissue irritation.[29] Ferric subsulfate, compounded as Monsel solution, is equally effective but has fallen out of favor somewhat due to the risk of permanent dyspigmentation from dermal iron placement.[30] The use of zinc paste, primarily composed of zinc chloride, was described by Frederic F. Mohs in the chemical fixation of skin cancer. However, despite its anti-tumor properties, it is now infrequently used in the context of MMS.[29]

Noncaustic Agents

Noncaustic hemostatic agents include physical substances that promote clot formation by providing a meshwork for platelet aggregation and coagulation.[31] Commonly used agents in this class include products containing gelatin, cellulose, collagen, or hydrophilic polymers, which can be formulated in vehicles such as powders and foams that are easy to apply. Although these agents are typically meant to dissolve over time, foreign body reactions have been reported.[32] Topical hemostatic agents with collagen are often bovine-derived and can lead to hypersensitivity reactions.[33] Additionally, applying cellulose agents has been associated with granulomatous reactions, delayed wound healing, and swelling at the application site.[31]

Physiologic Hemostatic Agents

The physiologic class of hemostatic agents mimics or enhances stages of the coagulation cascade following tissue application and includes thrombin derivatives, platelet gels, and fibrin sealants.[29] While physiologic agents are potent and effective at achieving hemostasis, this medication class is expensive and less frequently employed in dermatologic surgeries. Topical fibrin sealant has been associated with a hypersensitivity reaction in some patients and may rarely cause neurotoxicity.[27] Topical thrombin has been associated with an increased risk of coagulopathy due to subsequent antibody formation to bovine-derived thrombin after exposure; this adverse effect is uncommon.[34]

Areas of Ongoing Research

Brimonidine, an α-2 adrenergic agonist, may have a role as a hemostatic agent due to its vasoconstrictive properties. A small controlled study revealed the application of topical brimonidine gel before MMS resulted in decreased bleeding and a reduced need for electrocautery.[25] However, a later study reported altered mental status in patients following the application of topical brimonidine and ultimately recommended further evaluation of its safety before its routine use in MMS.[35]

Enhancing Healthcare Team Outcomes

Interprofessional collaboration among healthcare team members is essential to managing a patient undergoing MMS. These patients often inquire if it is necessary to stop antiplatelet or anticoagulation therapy before surgery; some patients preemptively hold these medications without discussion with the healthcare team. Nurses and medical assistants are essential in preoperative patient assessment and screening patients for antiplatelet or anticoagulant regimens.

Adequately counseling patients regarding the safety of perioperative antithrombotic therapy provides reassurance and minimizes the thrombotic risks associated with temporary discontinuation of the medication regimen. While consultation with the prescribing practitioner is rarely necessary, any concerns regarding the perioperative management of antithrombotic medications should be discussed directly with the prescribing practitioner.

Hemorrhagic complications associated with antithrombotic therapy can be minimized with meticulous attention to hemostasis and the postoperative application of a hemostatic dressing. Patients should receive education regarding postoperative wound care and the warning signs of hemorrhagic complications, including hematoma formation.

References


[1]

Alam M, Ibrahim O, Nodzenski M, Strasswimmer JM, Jiang SI, Cohen JL, Albano BJ, Batra P, Behshad R, Benedetto AV, Chan CS, Chilukuri S, Crocker C, Crystal HW, Dhir A, Faulconer VA, Goldberg LH, Goodman C, Greenbaum SS, Hale EK, Hanke CW, Hruza GJ, Jacobson L, Jones J, Kimyai-Asadi A, Kouba D, Lahti J, Macias K, Miller SJ, Monk E, Nguyen TH, Oganesyan G, Pennie M, Pontius K, Posten W, Reichel JL, Rohrer TE, Rooney JA, Tran HT, Poon E, Bolotin D, Dubina M, Pace N, Kim N, Disphanurat W, Kathawalla U, Kakar R, West DP, Veledar E, Yoo S. Adverse events associated with mohs micrographic surgery: multicenter prospective cohort study of 20,821 cases at 23 centers. JAMA dermatology. 2013 Dec:149(12):1378-85. doi: 10.1001/jamadermatol.2013.6255. Epub     [PubMed PMID: 24080866]

Level 2 (mid-level) evidence

[2]

Ruiz-Salas V, Sanmartin-Jiménez O, Garcés JR, Vilarrasa E, Miñano-Medrano R, Escutia-Muñoz B, Flórez-Menéndez Á, Artola-Igarza JL, Alfaro-Rubio A, Redondo P, Delgado-Jiménez Y, Sánchez-Schmidt J, Allende-Markixana I, García Bracamonte B, de la Cueva-Dobao P, Ciudad C, Carnero-González L, Vázquez-Veiga H, Sánchez-Sambucety P, Estebaranz JL, Botella-Estrada R, González-Sixto B, Martorell A, Morales-Gordillo V, Toll-Abelló A, Mayor-Arenal M, Suárez-Fernández R, Sainz-Gaspar L, Descalzo MA, Garcia-Doval I, REGESMOHS (Registro Español de Cirugía de Mohs). Complications Associated with Mohs Micrographic Surgery: Data from the Nationwide Prospective Cohort REGESMOHS. Dermatology (Basel, Switzerland). 2022:238(2):320-328. doi: 10.1159/000517010. Epub 2021 Aug 11     [PubMed PMID: 34380138]


[3]

Brown DG, Wilkerson EC, Love WE. A review of traditional and novel oral anticoagulant and antiplatelet therapy for dermatologists and dermatologic surgeons. Journal of the American Academy of Dermatology. 2015 Mar:72(3):524-34. doi: 10.1016/j.jaad.2014.10.027. Epub 2014 Dec 6     [PubMed PMID: 25486915]


[4]

Shah H, Frech FS, Dreyfuss I, Hernandez L, Nouri K. Perioperative anticoagulation recommendations for cutaneous oncologic surgery: a review of the literature. The Journal of dermatological treatment. 2022 Nov:33(7):2940-2945. doi: 10.1080/09546634.2022.2097161. Epub 2022 Jul 7     [PubMed PMID: 35775785]


[5]

Otley CC. Continuation of medically necessary aspirin and warfarin during cutaneous surgery. Mayo Clinic proceedings. 2003 Nov:78(11):1392-6     [PubMed PMID: 14601698]


[6]

Taylor O, Carr C, Greif C, Garcia A, Tran S, Srivastava D, Nijhawan RI. Postoperative bleeding complications associated with blood thinning agents during Mohs micrographic surgery: A retrospective cohort study. Journal of the American Academy of Dermatology. 2021 Jan:84(1):225-227. doi: 10.1016/j.jaad.2020.06.011. Epub 2020 Jun 8     [PubMed PMID: 32526317]

Level 2 (mid-level) evidence

[7]

Bordeaux JS, Martires KJ, Goldberg D, Pattee SF, Fu P, Maloney ME. Prospective evaluation of dermatologic surgery complications including patients on multiple antiplatelet and anticoagulant medications. Journal of the American Academy of Dermatology. 2011 Sep:65(3):576-583. doi: 10.1016/j.jaad.2011.02.012. Epub 2011 Jul 22     [PubMed PMID: 21782278]


[8]

Nast A, Ernst H, Rosumeck S, Erdmann R, Jacobs A, Sporbeck B. Risk of complications due to anticoagulation during dermatosurgical procedures: a systematic review and meta-analysis. Journal of the European Academy of Dermatology and Venereology : JEADV. 2014 Dec:28(12):1603-9. doi: 10.1111/jdv.12611. Epub 2014 Jul 30     [PubMed PMID: 25132203]

Level 1 (high-level) evidence

[9]

Billingsley EM, Maloney ME. Intraoperative and postoperative bleeding problems in patients taking warfarin, aspirin, and nonsteroidal antiinflammatory agents. A prospective study. Dermatologic surgery : official publication for American Society for Dermatologic Surgery [et al.]. 1997 May:23(5):381-3; discussion 384-5     [PubMed PMID: 9179249]


[10]

Kramer E, Hadad E, Westreich M, Shalom A. Lack of complications in skin surgery of patients receiving clopidogrel as compared with patients taking aspirin, warfarin, and controls. The American surgeon. 2010 Jan:76(1):11-4     [PubMed PMID: 20135932]

Level 2 (mid-level) evidence

[11]

Cook-Norris RH, Michaels JD, Weaver AL, Phillips PK, Brewer JD, Roenigk RK, Otley CC. Complications of cutaneous surgery in patients taking clopidogrel-containing anticoagulation. Journal of the American Academy of Dermatology. 2011 Sep:65(3):584-591. doi: 10.1016/j.jaad.2011.02.013. Epub 2011 Apr 21     [PubMed PMID: 21514003]


[12]

Koenen W, Kunte C, Hartmann D, Breuninger H, Moehrle M, Bechara FG, Schulze HJ, Lösler A, Löser CR, Wetzig T, Pappai D, Rapprich S, Weiß C, Faulhaber J. Prospective multicentre cohort study on 9154 surgical procedures to assess the risk of postoperative bleeding - a DESSI study. Journal of the European Academy of Dermatology and Venereology : JEADV. 2017 Apr:31(4):724-731. doi: 10.1111/jdv.14080. Epub 2017 Jan 19     [PubMed PMID: 27976439]


[13]

Isted A, Cooper L, Colville RJ. Bleeding on the cutting edge: A systematic review of anticoagulant and antiplatelet continuation in minor cutaneous surgery. Journal of plastic, reconstructive & aesthetic surgery : JPRAS. 2018 Apr:71(4):455-467. doi: 10.1016/j.bjps.2017.11.024. Epub 2017 Nov 28     [PubMed PMID: 29233507]

Level 1 (high-level) evidence

[14]

Shimizu I, Jellinek NJ, Dufresne RG, Li T, Devarajan K, Perlis C. Multiple antithrombotic agents increase the risk of postoperative hemorrhage in dermatologic surgery. Journal of the American Academy of Dermatology. 2008 May:58(5):810-6. doi: 10.1016/j.jaad.2008.01.014. Epub     [PubMed PMID: 18423258]

Level 2 (mid-level) evidence

[15]

Lewis KG, Dufresne RG Jr. A meta-analysis of complications attributed to anticoagulation among patients following cutaneous surgery. Dermatologic surgery : official publication for American Society for Dermatologic Surgery [et al.]. 2008 Feb:34(2):160-4; discussion 164-5     [PubMed PMID: 18093204]

Level 1 (high-level) evidence

[16]

Alcalay J, Alkalay R. Controversies in perioperative management of blood thinners in dermatologic surgery: continue or discontinue? Dermatologic surgery : official publication for American Society for Dermatologic Surgery [et al.]. 2004 Aug:30(8):1091-4; discussion 1094     [PubMed PMID: 15274698]


[17]

Syed S, Adams BB, Liao W, Pipitone M, Gloster H. A prospective assessment of bleeding and international normalized ratio in warfarin-anticoagulated patients having cutaneous surgery. Journal of the American Academy of Dermatology. 2004 Dec:51(6):955-7     [PubMed PMID: 15583588]

Level 2 (mid-level) evidence

[18]

Eilers RE Jr, Goldenberg A, Cowan NL, Basu P, Brian Jiang SI. A Retrospective Assessment of Postoperative Bleeding Complications in Anticoagulated Patients Following Mohs Micrographic Surgery. Dermatologic surgery : official publication for American Society for Dermatologic Surgery [et al.]. 2018 Apr:44(4):504-511. doi: 10.1097/DSS.0000000000001394. Epub     [PubMed PMID: 29140870]

Level 2 (mid-level) evidence

[19]

Antia C, Hone N, Gloster H. Perioperative complications with new oral anticoagulants dabigatran, apixaban, and rivaroxaban in Mohs micrographic surgery: A retrospective study. Journal of the American Academy of Dermatology. 2017 Nov:77(5):967-968. doi: 10.1016/j.jaad.2017.05.038. Epub     [PubMed PMID: 29029905]

Level 2 (mid-level) evidence

[20]

Kovich O, Otley CC. Thrombotic complications related to discontinuation of warfarin and aspirin therapy perioperatively for cutaneous operation. Journal of the American Academy of Dermatology. 2003 Feb:48(2):233-7     [PubMed PMID: 12582394]


[21]

Alam M, Goldberg LH. Serious adverse vascular events associated with perioperative interruption of antiplatelet and anticoagulant therapy. Dermatologic surgery : official publication for American Society for Dermatologic Surgery [et al.]. 2002 Nov:28(11):992-8; discussion 998     [PubMed PMID: 12460291]

Level 3 (low-level) evidence

[22]

Kirkorian AY, Moore BL, Siskind J, Marmur ES. Perioperative management of anticoagulant therapy during cutaneous surgery: 2005 survey of Mohs surgeons. Dermatologic surgery : official publication for American Society for Dermatologic Surgery [et al.]. 2007 Oct:33(10):1189-97     [PubMed PMID: 17903151]

Level 3 (low-level) evidence

[23]

Erickson SP, Schneider SL, Cohen JL, Alam M, Council ML. Perioperative Practices in Dermatologic Surgery. Dermatologic surgery : official publication for American Society for Dermatologic Surgery [et al.]. 2022 Sep 1:48(9):924-926. doi: 10.1097/DSS.0000000000003530. Epub 2022 Jul 15     [PubMed PMID: 35862644]


[24]

Khalifeh MR, Redett RJ. The management of patients on anticoagulants prior to cutaneous surgery: case report of a thromboembolic complication, review of the literature, and evidence-based recommendations. Plastic and reconstructive surgery. 2006 Oct:118(5):110e-117e. doi: 10.1097/01.prs.0000221114.01290.85. Epub     [PubMed PMID: 17016167]

Level 3 (low-level) evidence

[25]

Chen E, Patel RA, Kwak YJ, Huang CC. Randomized controlled pilot study of the preoperative use of brimonidine 0.33% topical gel for hemostasis in Mohs micrographic surgery. Journal of the American Academy of Dermatology. 2017 Dec:77(6):1114-1118. doi: 10.1016/j.jaad.2017.08.022. Epub 2017 Oct 12     [PubMed PMID: 29031658]

Level 1 (high-level) evidence

[26]

Chen DL, Carlson EO, Fathi R, Brown MR. Undermining and Hemostasis. Dermatologic surgery : official publication for American Society for Dermatologic Surgery [et al.]. 2015 Oct:41 Suppl 10():S201-15. doi: 10.1097/DSS.0000000000000489. Epub     [PubMed PMID: 26418686]


[27]

Henley J, Brewer JD. Newer hemostatic agents used in the practice of dermatologic surgery. Dermatology research and practice. 2013:2013():279289. doi: 10.1155/2013/279289. Epub 2013 Aug 7     [PubMed PMID: 23997764]


[28]

Strickler AG, Shah P, Bajaj S, Mizuguchi R, Nijhawan RI, Odueyungbo M, Rossi A, Ratner D. Preventing complications in dermatologic surgery: Presurgical concerns. Journal of the American Academy of Dermatology. 2021 Apr:84(4):883-892. doi: 10.1016/j.jaad.2020.10.099. Epub 2021 Jan 23     [PubMed PMID: 33497750]


[29]

Palm MD, Altman JS. Topical hemostatic agents: a review. Dermatologic surgery : official publication for American Society for Dermatologic Surgery [et al.]. 2008 Apr:34(4):431-45. doi: 10.1111/j.1524-4725.2007.34090.x. Epub 2008 Jan 31     [PubMed PMID: 18248471]


[30]

Amazon K, Robinson MJ, Rywlin AM. Ferrugination caused by Monsel's solution. Clinical observations and experimentations. The American Journal of dermatopathology. 1980 Fall:2(3):197-205     [PubMed PMID: 7258552]

Level 3 (low-level) evidence

[31]

Iyengar S, Yeager DG, Cohen JL, Ozog DM. Update and Review of Bleeding Considerations in Dermatologic Surgery: Hemostatic Techniques and Treatment Strategies for Bleeding Complications. Dermatologic surgery : official publication for American Society for Dermatologic Surgery [et al.]. 2020 Feb:46(2):203-212. doi: 10.1097/DSS.0000000000002138. Epub     [PubMed PMID: 31592926]


[32]

Glick JB, Kaur RR, Siegel D. Achieving hemostasis in dermatology-Part II: Topical hemostatic agents. Indian dermatology online journal. 2013 Jul:4(3):172-6. doi: 10.4103/2229-5178.115509. Epub     [PubMed PMID: 23984226]


[33]

Dhillon S. Fibrin sealant (evicel® [quixil®/crossealâ„¢]): a review of its use as supportive treatment for haemostasis in surgery. Drugs. 2011 Oct 1:71(14):1893-915. doi: 10.2165/11207700-000000000-00000. Epub     [PubMed PMID: 21942978]

Level 3 (low-level) evidence

[34]

Chapman WC, Singla N, Genyk Y, McNeil JW, Renkens KL Jr, Reynolds TC, Murphy A, Weaver FA. A phase 3, randomized, double-blind comparative study of the efficacy and safety of topical recombinant human thrombin and bovine thrombin in surgical hemostasis. Journal of the American College of Surgeons. 2007 Aug:205(2):256-65     [PubMed PMID: 17660072]

Level 1 (high-level) evidence

[35]

Shagalov DR, Taylor D, Schleichert R, Weiss J, Weiss E. Association of Central Nervous System Depression With Topical Brimonidine When Used for Hemostasis: A Serious Adverse Event. JAMA dermatology. 2017 Jun 1:153(6):575-577. doi: 10.1001/jamadermatol.2017.0247. Epub     [PubMed PMID: 28403392]