Characterized as a vascular skin reaction, acute urticaria is marked by transient, erythematous, intensely pruritic raised wheals with or without angioedema.1 According to the 2016 US National Hospital Ambulatory Medical Care Survey, acute urticaria accounts for nearly 450,000 emergency department visits annually.2 Although patients can present with acute urticaria as the primary reason for the emergency department visit, acute urticaria may also manifest as a symptom of other conditions, such as allergic reactions (eg, allergy, anaphylaxis).1
Antihistamines are considered first-line treatment for acute urticaria.1,3 Some physicians may prefer the rapid onset of action of an intravenous (IV) formulation rather than its oral counterpart in an acute situation.3 Before the availability of IV cetirizine, the only IV antihistamine available was first-generation diphenhydramine.
In a phase 3 clinical trial involving 262 patients (NCT02935699), the mean change from baseline in patient-rated pruritus severity score (on a scale of 0-3) was –1.6 (standard deviation [SD] 0.9) for IV cetirizine versus –1.5 (SD 1.0) for IV diphenhydramine, with a treatment difference of 0.1 (95% confidence interval, –0.1-0.3; P = .35), indicating no statistical difference in the primary efficacy end point.4 These adverse effects were less common with IV cetirizine versus IV diphenhydramine in the pivotal trial.4 As a secondary end point, patient-rated sedation scores (on a scale of 0-3) were consistently lower with IV cetirizine compared with IV diphenhydramine: 0.2 (SD 0.8) versus 0.7 (SD 0.9) at 1 hour (P = .003); the scores were 0.1 (SD 0.8) versus 0.5 (SD 0.9) at 2 hours (P = .03); and the scores were 0.1 (SD 0.8) versus 0.5 (SD 0.9) at discharge (P = .04).4 Less sedation may be a factor in allowing patients to be ready for discharge sooner.4 IV cetirizine was associated with a shorter duration of stay (median of 1.4 hours) compared with IV diphenhydramine (median of 2.0 hours; P = .005).4 In addition, the 24-hour duration of action of IV cetirizine may have contributed to a trend toward fewer return visits than IV diphenhydramine (3.9% for IV cetirizine vs 9.6% for IV diphenhydramine return visits related to urticaria within 24 hours).4 A shorter duration of stay and fewer return visits may translate into cost-savings from the perspective of a US emergency department.
The primary objective of this analysis was to compare total emergency department costs between IV diphenhydramine and IV cetirizine as treatment options for acute urticaria by modeling clinical, facility, and cost parameters for hospital formulary considerations. This analysis is intended to facilitate discussions among healthcare decision makers when considering the addition of a second-generation IV antihistamine to formulary in the emergency department setting for the treatment of acute urticaria.
We developed a budget impact model in Microsoft Excel for Microsoft 365 using principles of good practice as recommended by the International Society for Pharmacoeconomics and Outcomes Research.5 This budget impact model was designed to calculate the incremental budget impact of treating patients with acute urticaria with IV cetirizine rather than standard of care (IV diphenhydramine), considering both cost per treated patient and overall emergency department patient volume (Figure 1).
We modeled the patient population to reflect the adults and children presenting to emergency departments with acute urticaria, populations likely eligible for treatment with an IV antihistamine. We assumed that all patients presenting to the emergency department with acute urticaria (or acute urticaria as a symptom of other conditions [eg, anaphylaxis, allergy]) will receive an IV antihistamine in the acute emergency care setting, as there are limited data to inform the percentage of patients who may receive an oral antihistamine in this setting. In addition, given that the time to maximal concentration is 1 hour for oral cetirizine (1.7 hours after food) compared with <2 minutes for IV cetirizine (10-mg injection),6 IV antihistamine use was reasonable. In this budget impact model, we tried to focus on the subset of patients who may require an IV antihistamine rather than an oral antihistamine. The model was developed from the perspective of a US emergency department, with calculated emergency department costs, revenue, and various other parameters to estimate budget impact over a 1-year time frame.
Based on the number of pediatric and adult patients visiting the emergency department each year, the proportion of patients presenting with acute urticaria was estimated using nationally aggregated epidemiology data.2 Consistent with the phase 3 clinical trial, the model included either IV diphenhydramine 50 mg or IV cetirizine 10 mg administered as a single injection as the 2 treatment options. The base-case treatment mix would be a scenario before the availability or use of IV cetirizine, so the IV antihistamine utilization was modeled to be 100% IV diphenhydramine (Figure 1A). The projected treatment mix would be based on the scenario with IV cetirizine on the formulary, so we modeled the IV antihistamine utilization to be 100% IV cetirizine (Figure 1B). These scenarios demonstrated the 2 extremes, the base-case representing a time before the adoption of IV cetirizine and the projected case representing a time after full adoption onto the formulary. In either scenario, the drug cost, number of minutes per emergency department visit, and the emergency department operational cost per minute were used to estimate the emergency department expenses given the total emergency department patient volume, reimbursement rates per visit, and net revenue per emergency department patient. By comparing the 2 scenarios (Figure 1A and 1B), the budget impact of IV cetirizine versus IV diphenhydramine can be calculated.
The analysis utilized an epidemiologic approach to set facility data inputs based mainly on national aggregated data from the 2016 US National Hospital Ambulatory Medical Care Survey conducted by the Centers for Disease Control and Prevention (CDC).2 This CDC resource reported the age distribution for emergency department visits to be 18.8% for patients aged <15 years, 65.3% for those aged 15 to 65 years, and 15.9% for those aged ≥65 years (Table 1A).2
We estimated the number of visits for acute urticaria in 2 hypothetical scenarios: Case 1 with 50,000 all-cause emergency department vtableannually and Case 2 with 100,000 all-cause emergency department visits annually. Betableacute urticaria may manifest as a symptom of other conditions (eg, allergic reaction), the percentage of emergency department visits included those with either a primary diagnosis of acute urticaria only or with a secondary diagnosis alongside anaphylaxis or allergy. The Agency for Healthcare Research and Quality Healthcare Cost and Utilization Project database was queried for all-cause emergency department visits and emergency department visits attributed to International Classification of Diseases, Tenth Revision codes for acute urticaria (L50.0-L50.9), anaphylaxis (T78.00XA-T78.2XXD), and allergy (T78.40XA).7 The ratio of all-cause emergency department visits to emergency department visits due to acute urticaria was used to estimate the proportion of emergency department visits that are due to acute urticaria by age-group (Table 1B).
Costs and Revenue
An all-cause operating cost of $2.73 per minute was calculated from the 1998 average cost of a nontrauma emergency department visit of $295 as reported by Bamezai and colleagues,8 inflated to 2019 dollars to $605 using the Consumer Price Index reported by the US Bureau of Labor Statistics,9 divided by the weighted average duration of a nontrauma emergency department visit of 221.5 minutes, estimated from the CDC data (Table 1A).2 This figure is consistent with the median emergency department length of stay of 274 minutes reported in a longitudinal study of 2619 US hospitals.10 The duration of acute urticaria visits is based on head-to-head data from the pivotal phase 3 trial comparing IV cetirizine and IV diphenhydramine and supplemented by data on file (Table 1C).4,11 Because data regarding the duration of acute urticaria visits are not often published, our point estimates were based on the best available information in the literature.
The net revenue that a facility can anticipate depends on the payer type. The CDC reported the typical payer mix across the country for emergency department visits was 33.2% private insurance, 18.6% Medicare, 39.4% Medicaid, and 8.8% uninsured (Table 1A).2 Total revenue per visit (all-cause and emergency department) was calculated based on the operating cost per minute combined with the cost-to-revenue ratio for each payer type.12 Higher revenues can be realized with private insurance (39.6%), but losses are generally more common among patients receiving Medicare (–15.6%) and Medicaid (–35.9%), and in patients who are uninsured (–54.4%) based on data from the published literature (Table 1A).12
Revisits within a 24-hour period after discharge would typically not bring additional reimbursement because it would be considered by the payers as a continuation of the previous visit. The defaults for the percentage of patients returning to any emergency department or clinic due to acute urticaria within 24 hours of patient discharge are based on head-to-head data from the pivotal phase 3 trial and supplemented by data on file (Table 1C).4,11 Although there may not be any additional reimbursement from the payers for a return visit within 24 hours, there will likely be costs associated with treatment during the revisit. The costs may or may not be the same as the original visit (data not available); however, we modeled the cost of the return visit to be the same as the index visit with the assumption that the treatment strategy and the amount of healthcare resources utilized would be similar (Table 1C). This is a rational approach given that it is otherwise challenging to predict how individual hospitals may manage acute urticaria treatment in their emergency departments.
Drug costs may vary, depending on contractual agreements, and may or may not be similar to the wholesale acquisition cost (WAC). For IV diphenhydramine and IV cetirizine, the drug cost was modeled using the lowest reported WAC per vial reported via Medi-Span (Table 1C).13,14 A drug markup of 100% was chosen for IV diphenhydramine as a base case, conservatively allowing for a wider range of drug revenues since its low cost of <$1 would ultimately have negligible effects on the overall budget. Markup for IV cetirizine was set at 3% because the established Medicare reimbursement by the Centers for Medicare & Medicaid Services (CMS) is WAC + 3% (Table 1C).15
Model Analyses and Outputs
Model outputs for the analysis of IV diphenhydramine compared with IV cetirizine on formulary for the treatment of acute urticaria include:
- Total annual revenue for visits due to acute urticaria, calculated as the sum of the revenue for the emergency department visit and the drug revenue, annualized
- Cost of initial visits for acute urticaria, calculated based on the operating cost for the emergency department visit and the drug cost
- Cost of return visits for acute urticaria, calculated based on the operating cost for the return emergency department visit and the drug cost, adjusted for the probability of any return visit within 24 hours
- Incremental annual revenue from additional patients seen because patients who receive IV cetirizine may be discharged earlier than patients who receive IV diphenhydramine (as shown in the phase 3 acute urticaria clinical trial5). The early availability of an empty bed may allow for additional patients to be seen in the event that the emergency department is operating at full capacity. This increases the likelihood for additional revenue as more patients can be treated. This output is calculated from the incremental revenue per patient, multiplied by the number of additional patients who can be seen per year
- Total net revenue per year, calculated from the emergency department revenue for acute urticaria visits, minus the total cost of visits for acute urticaria
- Overall budget impact, calculated as the difference in total annual costs and revenue for scenarios with the use of IV cetirizine on the formulary for acute urticaria compared with IV diphenhydramine
Sensitivity and Scenario Analyses
One-way sensitivity analyses were performed to evaluate the most impactful model parameters on the budget impact. Two scenario analyses were conducted: Case 1 with 50,000 all-cause emergency department visits annually and Case 2 with 100,000 all-cause emergency department visits annually.
In the first emergency department with 50,000 all-cause visits each year, an estimated 204 visits were attributed to acute urticaria as the reason for the visit (Figure 2). Annual revenue related to these initial emergency department visits equates to $130,689 plus revenue based on the drug markup for antihistamine medication selected for treatment.
In the landscape where IV diphenhydramine accounts for 100% of the IV antihistamine treatment, 20 emergency department revisits are expected each year due to acute urticaria–specific complications arising within 24 hours of discharge. Patients with acute urticaria account for a total of 27,145 minutes (452 hours) each year in the emergency department when IV diphenhydramine is utilized. The estimated net annual budget impact to the emergency department was $56,768 (the annual emergency department revenue for acute urticaria visits of $131,056 minus a cost of $67,782 for initial visits and $6507 for return visits; Figure 2).
With the introduction of IV cetirizine to the formulary, we considered a scenario where IV cetirizine accounts for 100% of the IV antihistamine treatment for acute urticaria. Eight emergency department revisits are expected each year due to acute urticaria–specific complications arising within 24 hours of discharge, compared with the 20 revisits with IV diphenhydramine. This decrease of 12 revisits accounts for $2262 in additional costs when IV diphenhydramine is utilized rather than IV cetirizine. Because patients receiving IV cetirizine on average are discharged more quickly, acute urticaria accounts for only 18,090 minutes (301 hours) of emergency department time when IV cetirizine is utilized. It is estimated that 41 additional patients could be seen each year in the emergency department with the freed bed space and resources, which would result in an incremental $1428 annual net revenue from additional patients seen. The estimated net budget impact was $84,644 (the annual emergency department revenue for acute urticaria visits of $196,295 minus a cost of $108,835 for initial visits and $4245 for return visits; Figure 2).
Altogether, the adoption of IV cetirizine had a positive budget impact of $27,876 (Figure 2). If allergy and anaphylaxis visits were included as reasons for visits (341 visits), net annual impact was $46,456.
In the second emergency department with 100,000 all-cause visits each year, an estimated 409 visits were attributed to acute urticaria as the reason for the visit (Figure 3). Revenue related to these initial emergency department visits equates to $261,378 plus revenue based on the antihistamine medication selected for treatment.
In the landscape where IV diphenhydramine accounts for 100% of the IV antihistamine as the treatment, 39 emergency department revisits are expected each year due to acute urticaria–specific complications arising within 24 hours of discharge. Patients with acute urticaria account for a total of 54,289 minutes (905 hours) each year in the emergency department when IV diphenhydramine is utilized. The estimated net annual budget impact to the emergency department was $113,536 (the annual emergency department revenue for acute urticaria visits of $262,113 minus a cost of $135,563 for initial visits and $13,014 for return visits; Figure 3).
With the introduction of IV cetirizine to the formulary, we considered a scenario where IV cetirizine accounts for 100% of the IV antihistamine treatment. Sixteen emergency department revisits are expected each year due to acute urticaria–specific complications arising within 24 hours of discharge, as compared with 39 revisits with IV diphenhydramine. This decrease of 23 revisits accounts for $4525 in additional costs when IV diphenhydramine is utilized rather than IV cetirizine. Because patients receiving IV cetirizine on average are discharged more quickly, patients with acute urticaria account for only 36,179 minutes (603 hours) of emergency department time when IV cetirizine is utilized. It is estimated that 82 additional patients could be seen each year in the emergency department with the freed bed space and resources, which would result in an incremental $2856 annual income from additional patients seen. Again, for an emergency department not operating at full capacity, this additional net revenue accounting for <2% of the total revenues would not be realized. The estimated net annual budget impact was $169,287 (the annual emergency department revenue for acute urticaria visits of $392,591 minus a cost of $217,671 for initial visits and $8489 for return visits; Figure 3).
The estimated outcomes in this case had a similar trend for IV cetirizine with a positive net annual budget impact of $55,752 (Figure 3). If allergy and anaphylaxis visits were included (681 visits), net annual impact was $92,913.
Each parameter was individually varied ±10% in a one-way sensitivity analysis to detect the most impactful model parameters. For instance, the default duration of an acute urticaria visit was based on the IV cetirizine pivotal phase 3 trial, which demonstrated that use of IV diphenhydramine resulted in a median duration of 121.2 minutes and 85.2 minutes for IV cetirizine.4 In the sensitivity analysis, the IV diphenhydramine duration of visit varied from a low of 109.1 (–10%) to a high of 133.3 (+10%) minutes. For IV cetirizine, the duration of visit varied from a low of 76.7 (–10%) to a high of 93.7 (+10%) minutes, and the drug cost per acute urticaria visit varied from a low of $270 (–10%) to a high of $330 (+10%).
For Case 1, this resulted in a budget impact that varied from $20,037 (low result) to $35,714 (high result) when IV diphenhydramine duration of visit was varied ±10%, indicating with this $15,677 variability that IV diphenhydramine duration of visit was the most impactful parameter. When the duration of visit for IV cetirizine was varied ±10%, the budget impact varied from $33,100 (low result) to $22,652 (high result), with a range of $10,447 in variability. When the cost of IV cetirizine was varied ±10%, the budget impact varied from $21,315 (low result) to $34,437 (high result), with a range in variability of $13,121, indicating that this was the second most impactful parameter within the model (Appendix Figure A).
For Case 2, the budget impact ranged from $40,075 (low result) to $71,429 (high result) when the IV diphenhydramine duration of visit was varied ±10%. This $31,354 variability demonstrated that once again the IV diphenhydramine duration of visit was the most impactful parameter. When the duration of visit for IV cetirizine was varied ±10%, the budget impact varied from $66,199 (low result) to $45,304 (high result) with a range of $20,895 in variability. Similar to Case 1, when the cost of IV cetirizine was varied ±10%, this was the second most impactful parameter as the budget impact varied from $42,631 (low result) to $68,873 (high result) with a range in variability of $26,243 (Appendix Figure B).
The parameters influencing the budget impact model results the most were the mean duration of visit for both IV diphenhydramine and IV cetirizine and the drug cost per acute urticaria visit for IV cetirizine across both cases (Appendix Figure A and B).
The American Academy of Family Physicians (AAFP) management recommendations and the American Academy of Emergency Medicine (AAEM) treatment guidelines for acute urticaria both recommend second-generation H1-antihistamines as first-line therapy because they are less sedating than the first-generation H1-antihistamines.1,16 Note that at the time of publication of these guidelines, the only available IV formulation was diphenhydramine.1 IV cetirizine has been available since October 2019 for the treatment of acute urticaria in adults and children aged ≥6 months.6
The results of this budget impact model analysis suggest the potential for cost-savings with the adoption of IV cetirizine on a hospital formulary. In addition to direct quantitative benefits, IV cetirizine may result in improved patient outcomes. The time spent in the treatment center and the need to revisit within 24 hours of discharge are potential quality indicators for the treatment received. In the IV cetirizine phase 3 pivotal trial, the median time spent in the treatment center was shorter with patients treated with IV cetirizine compared with the IV diphenhydramine group.4 According to data on file and the phase 3 trial, the proportion of patients returning to any emergency department or clinic for acute urticaria within 24 hours was also lower in the IV cetirizine group compared with the diphenhydramine group.4,11 Both the shorter length of stay and lower number of emergency department revisits associated with IV cetirizine contributed to the positive financial impact illustrated in the budget impact model and provided value as quality measures important for health systems and their emergency departments. For example, “Median Time from ED Arrival to ED Departure for Discharged ED Patients” (which includes time spent in the treatment center) is a CMS quality measure reported by hospitals, and it can affect funding/reimbursement.17 From an emergency department perspective, earlier discharge may allow for more patients to be seen each year (and less resource utilization), and fewer return visits may indicate less expense due to complications, given the lack of reimbursement for revisits—both factors that may support the economic value of using IV cetirizine despite it having a higher drug cost.
Both the AAFP treatment recommendations and the AAEM guidelines for treatment of acute urticaria suggest adding H2-antihistamines if symptoms are not sufficiently controlled with H1-antihistamine monotherapy, and corticosteroids for severe cases.1,16 As our focus was limited to H1-antihistamines available for IV administration, evaluation of any additional effects on the budget impact from use of oral H1-antihistamines, any H2-antihistamines, and/or corticosteroids used in standard clinical practice was outside our scope.
Many factors are considered when making formulary decisions—some are more logistical in nature (eg, processes involved in updating protocols, establishment of prior authorization) and others involve the financial factors (eg, bundled pricing, budget impact). Because this report is simply intended to inform healthcare decision makers regarding the budget impact of adopting IV cetirizine on the formulary, the other aspects impacting a formulary decision were beyond the scope of this discussion.
Because a national aggregate was utilized in our epidemiologic approach in this budget impact model, these estimates may differ given specific urban, suburban, or rural settings and may not be applicable to every situation. The number of patients treated with IV antihistamines each year may be overestimated because use of oral antihistamines in this setting was not considered. Treatment pattern data specifically for patients presenting to the emergency department with acute urticaria are not widely available.
Some group purchasing organizations, and those within the 340B Drug Pricing Program, will have variations in drug pricing that differ from the drug costs presented in this budget impact model. The adjustment for inflation of the 1998 emergency department operating cost data8 utilized in this budget impact model does not account for any changes in standard clinical practice over time; however, published data are limited on the hospital-incurred costs of a nontrauma emergency department visit. In addition, a factor that would decrease the positive net effect with IV cetirizine is a lower commercial payer population. Note that these cases were modeled using the weighted national average of payer types as depicted in Table 1. Finally, revenue from additional patients that can be seen per year may not be as relevant to an emergency department with relatively low volumes, particularly when not at full capacity. However, this additional net revenue accounted for <2% of the total revenues per year gained from switching to IV cetirizine.
Adoption of the second-generation H1-antihistamine, IV cetirizine, for acute urticaria treatment in the emergency department setting has the potential to have a positive budget impact, while also expanding treatment options for patients with acute urticaria. The positive impact was maintained across scenarios and sensitivity analysis, where IV cetirizine was shown to be consistently cost-saving when adjusting each model parameter by ±10%. These outcomes were driven by the shorter duration of visits, fewer 24-hour return visits, and higher drug revenue associated with IV cetirizine compared with the first-generation antihistamine, IV diphenhydramine.18 This budget impact model may help hospital formulary personnel to assess the overall budget impact and value of incorporating IV cetirizine on formulary (vs evaluating drug cost alone), or they may use this framework as a basis for conducting an internal budget impact assessment.
Modeling support was provided by Curta, Inc, which received funding for development of the budget impact model. Medical writing support was provided by Forward WE Go, a division of Wesley Enterprise, Inc, which received funding for preparation of the budget impact model report and manuscript. The authors would like to thank Brandon Brent, PharmD, of TerSera Therapeutics, and Jack Timmons, PharmD, of Curta, Inc, for contributions to the development of the budget impact model.
This study was funded by TerSera Therapeutics.
Author Disclosure Statement
Dr Bloudek and Dr Ho received funding from TerSera Therapeutics for this study; Dr Kapur and Dr Brent are employees of TerSera Therapeutics.
- Schaefer P. Acute and chronic urticaria: evaluation and treatment. Am Fam Physician. 2017;95:717-724.
- Centers for Disease Control and Prevention. National hospital ambulatory medical care survey: 2017 emergency department summary tables. www.cdc.gov/nchs/data/nhamcs/web_tables/2017_ed_web_tables-508.pdf. Accessed January 21, 2021.
- Bernstein JA, Lang DM, Khan DA, et al. The diagnosis and management of acute and chronic urticaria: 2014 update. J Allergy Clin Immunol. 2014;133:1270-1277.
- Abella BS, Berger WE, Blaiss MS, et al. Intravenous cetirizine versus intravenous diphenhydramine for the treatment of acute urticaria: a phase III randomized controlled noninferiority trial. Ann Emerg Med. 2020;76:489-500.
- Sullivan SD, Mauskopf JA, Augustovski F, et al. Budget impact analysis—principles of good practice: report of the ISPOR 2012 Budget Impact Analysis Good Practice II Task Force. Value Health. 2014;17:5-14.
- Quzyttir (cetirizine hydrochloride injection), for intravenous use [prescribing information]. TerSera Therapeutics; March 2020. https://documents.tersera.com/quzyttir/QuzyttirPrescribingInformation.pdf. Accessed March 2, 2021.
- Agency for Healthcare Research and Quality. HCUPnet: Healthcare Cost and Utilization Project. https://hcupnet.ahrq.gov. Accessed October 23, 2019.
- Bamezai A, Melnick G, Nawathe A. The cost of an emergency department visit and its relationship to emergency department volume. Ann Emerg Med. 2005;45:483-490.
- US Bureau of Labor Statistics. Consumer Price Index. All urban consumers. Medical Care Component. Washington, DC: 2019. www.bls.gov/cpi/data.htm. Accessed September 19, 2019.
- Chang AM, Lin A, Fu R, et al. Associations of emergency department length of stay with publicly reported quality-of-care measures. Acad Emerg Med. 2017;24:246-250.
- Data on file. TerSera Therapeutics, LLC.
- Wilson M, Cutler D. Emergency department profits are likely to continue as the Affordable Care Act expands coverage. Health Aff (Millwood). 2014;33:792-799.
- Medi-Span. Clinical Drug Information, diphenhydramine HCl; 2020.
- Medi-Span. Clinical Drug Information, Quzyttir; 2020.
- Centers for Medicare & Medicaid Services. Addendum B.-Final OPPS payment by HCPCS code for CY 2020. October 2020. www.cms.gov/medicaremedicare-fee-service-paymenthospitaloutpatientppsaddendum-and-addendum-b-updates/october-2020-0. Accessed October 7, 2020.
- Winters M; American Academy of Emergency Medicine. Clinical practice guideline: initial evaluation and management of patients presenting with acute urticaria or angioedema. July 10, 2006. www.aaem.org/resources/statements/position/clinical-practice-guideline-initial-evaluation-and-management-of-patients-presenting-with-acute-urticaria-or-angioedema. Accessed May 11, 2021.
- Centers for Medicare & Medicaid Services. Hospital Outpatient Quality Reporting Program. June 24, 2022. www.cms.gov/Medicare/Quality-Initiatives-Patient-Assessment-Instruments/HospitalQualityInits/HospitalOutpatientQualityReportingProgram. Accessed November 26, 2019.
- Bloudek LM, Ho LK, Kapur N, Brent LD. Budget impact of intravenous cetirizine hydrochloride for the treatment of acute urticaria in the United States emergency department setting. Poster presented at the American Society of Health-System Pharmacists Midyear Clinical Meeting and Exhibition; December 6-10, 2020. Poster P72.