From the Guidelines
For an allergic reaction, the patient should be given hydroxyzine, not hydralazine. Hydroxyzine is an antihistamine that works by blocking H1 histamine receptors, which helps reduce allergic symptoms like itching, hives, and swelling 1. The typical adult dose ranges from 25-50 mg every 6-8 hours as needed, with a maximum daily dose of 200 mg. For children, the dose is typically 0.5-1 mg/kg every 6 hours. Hydroxyzine may cause drowsiness, so patients should be cautioned about driving or operating machinery after taking it.
In the context of allergic reactions, it is crucial to administer the correct medication to prevent worsening of symptoms and potential life-threatening complications. According to the evidence, antihistamines like hydroxyzine are recommended for the management of mild to severe reactions, including those caused by taxanes, liposomal doxorubicin, or biotherapeutic agents 1. In contrast, hydralazine is an antihypertensive medication used to treat high blood pressure and has no role in treating allergic reactions.
Key points to consider when administering hydroxyzine for an allergic reaction include:
- Monitoring for potential side effects, such as drowsiness and dry mouth
- Adjusting the dose according to the patient's response and medical history
- Considering concurrent administration of other medications, such as H2 blockers and corticosteroids, as recommended in the guidelines 1
- Referring patients with life-threatening reactions to an academic center with expertise in desensitization, if necessary 1.
From the FDA Drug Label
Oral hydroxyzine hydrochloride is contraindicated in patients with known hypersensitivity to hydroxyzine hydrochloride products, and in patients with known hypersensitivity to cetirizine hydrochloride or levocetirizine hydrochloride. Hydroxyzine is contraindicated in patients with a prolonged QT interval. Hydroxyzine, when administered to the pregnant mouse, rat, and rabbit induced fetal abnormalities in the rat and mouse at doses substantially above the human therapeutic range. Clinical data in human beings are inadequate to establish safety in early pregnancy. Until such data are available, hydroxyzine is contraindicated in early pregnancy. Hydroxyzine is contraindicated for patients who have shown a previous hypersensitivity to any component of this medication.
The patient should be given hydralazine for an allergic reaction, as hydroxyzine is contraindicated in patients with known hypersensitivity to hydroxyzine hydrochloride products 2.
From the Research
Allergic Reaction Treatment
For an allergic reaction, the choice between hydroxyzine and hydralazine depends on the specific circumstances of the reaction.
- Hydroxyzine is an antihistamine that can be used to treat allergic reactions, particularly those with mild to moderate symptoms 3, 4.
- Hydralazine, on the other hand, is a vasodilator that is not typically used as a first-line treatment for allergic reactions.
Antihistamine Use in Allergic Reactions
Antihistamines, such as hydroxyzine, can be beneficial in the management of allergic reactions, particularly when used in conjunction with epinephrine 5, 6.
- A study published in the Annals of Allergy, Asthma, and Immunology found that patients treated with prehospital antihistamines were less likely to have uncontrolled reactions and be admitted to the hospital after the reaction 5.
- However, it is essential to note that antihistamines should not be used as a replacement for epinephrine in the treatment of anaphylaxis 6.
Hydroxyzine vs. Hydralazine
There is no direct comparison between hydroxyzine and hydralazine in the context of allergic reactions in the provided studies.
- Hydroxyzine has been shown to be effective in suppressing histamine- and allergen-induced skin reactions, particularly when compared to second-generation antihistamines 4.
- Hydralazine is not mentioned in the provided studies as a treatment for allergic reactions, and its use in this context is not supported by the available evidence.