Which medications in the drug class H1 Antagonists (first-generation antihistamines) are used in the treatment of Acute Urticaria?

Updated: Mar 21, 2018
  • Author: Henry K Wong, MD, PhD; Chief Editor: Michael A Kaliner, MD  more...
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H1 Antagonists (first-generation antihistamines)

Primary agents used for urticaria. [11] The older, first-generation H1 antagonists (eg, diphenhydramine, hydroxyzine) are effective in reducing the lesions and pruritus but can produce adverse effects, such as drowsiness and anticholinergic effects. [50]  These are no longer first-line treatments, but can be helpful when sedation is needed.

The first-generation agents can be useful if administered at bedtime because the sedative effects can help with sleep; however, the patient must be warned that the sedation and cognitive effects may continue until the next day. Any patient who is taking a medication that has potential sedative effects should be cautioned about driving and operating heavy machinery. Commonly used first-generation agents include diphenhydramine, hydroxyzine, doxepin, chlorpheniramine, and cyproheptadine.

Diphenhydramine (Benadryl, Diphen, Banophen, Genahist)

Diphenhydramine is a common first-generation agent that is available without a prescription in the United States and can be used to control pruritus. It acts by competitive inhibition of histamine at the H1 receptor, which mediates the wheal-and-flare reactions.


Cyproheptadine is a first-generation agent and historically has been a drug of choice for prophylaxis of primary acquired cold-induced urticaria.

Chlorpheniramine (Chlor-Trimeton, Aller-Chlor, Ed-Chlortan)

Chlorpheniramine is a first-generation agent and is one of the safest antihistamines to use during pregnancy.

Hydroxyzine (Vistaril)

Hydroxyzine is used for control of pruritus. It is an effective first-generation agent but frequently produces sedation, particularly with higher doses. Historically, it has been considered a drug of choice for cholinergic urticaria. SC and IV are not recommended administration routes. Hydroxyzine also may suppress histamine activity in the subcortical region of the CNS.

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