Clinical Trial Comparing JDP-205 to Diphenhydramine Injection for the Treatment of Acute Urticaria

Inclusion Criteria: 1. Male or female patients with a diagnosis of acute urticaria who need treatment with antihistamine to alleviate their symptoms; 2. 18 years of age or older; 3. Be willing and able to give informed consent; 4. Patients with a Patient rated Pruritus Severity Score ≥ 1 Exclusion Criteria: 1. Receipt of an investigational drug or device, within the past 30 days; 2. Patients in whom an antihistamine may be contraindicated (e.g. narrow angle glaucoma, symptomatic prostatic hypertrophy); 3. Patients who, in the opinion of the investigator, may not tolerate an IV injection of diphenhydramine 50 mg, or cetirizine 10 mg; 4. Receipt of any antihistamine (H1 antagonist) within the past 2 hours regardless of the route of administration, e.g. diphenhydramine, cetirizine, loratadine, fexofenadine, levocetirizine, desloratadine; 5. Receipt of an H2 antagonist within the past 2 hours; 6. Receipt of doxepin within the past 2 hours; doxepin is an antidepressant, but it also has antihistamine properties; 7. Receipt of steroids by the oral, IV, IM, or inhalational routes route within the past 4 hours to manage an acute allergic reaction; 8. Receipt of epinephrine (EpiPen or any other brand) within the past 20 minutes; 9. Anaphylaxis prior to the acute anaphylactic symptoms having been treated. 10. Has known allergy to hydroxyzine, cetirizine or levocetirizine, or diphenhydramine; 11. Pregnancy or breastfeeding; 12. Patients who have an acute allergic reaction to medication they are taking (e.g. antibiotics, NSAIDs, etc.) and who cannot stop the medication; 13. Patients who, based on their medical history or in the opinion of the investigator, have chronic urticaria, hereditary angioedema, urticaria refractory to antihistamines, or dermatological disease that interferes with evaluation of a therapeutic response; 14. Any condition that in the view of the investigator makes the subject unsuitable for enrollment in this study; 15. History of HIV or other known immunodeficiency; 16. Major medical or psychiatric illness, other than acute urticaria, at the time of presentation; 17. Inability to provide informed consent. 18. Patients on concomitant p-glycoprotein inhibitors