Are there any clinically relevant differences between the two formulations regarding efficacy and/or side effects? Are there pharmacokinetic or pharmacodynamic differences? Are there any advantages to one or the other? (Ex: is one form considered better for anxiety? Does one form get absorbed faster?, etc.)
Hydroxyzine - Differences between HCl vs. pamoate?
Question posted by eman10375 on 2 days 2 hours ago
Last updated on 18 April 2025
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Answers
WildcatVet
1 day 19 hours ago
Hi, eman!
I'll give you this from the literature:
"Hydroxyzine hydrochloride (Atarax) and hydroxyzine pamoate (Vistaril) are both antihistamines used to treat anxiety, itching, and other conditions, but they differ primarily in their dosage forms and cost. Hydroxyzine HCl is available as tablets, syrup, and solution for injection, while hydroxyzine pamoate is only available as capsules. There's no clinical difference between the two, so the choice often comes down to preference for dosage form and cost."
I don't know if there's a difference in onset and duration. Perhaps you could ask the advice of your pharmacist. They are very qualified in drug pharmacology.
Best regards,
Wildcat
WildcatVet
1 day 19 hours ago
Here's more:
"Bioavailability and absorption: Hydroxyzine HCl is often reported to have a quicker onset of action than hydroxyzine pamoate. However, both forms of hydroxyzine start to work at about the same rate, usually within 30 minutes to an hour.
Usage: Both medications can be used for anxiety and itching, but hydroxyzine pamoate is sometimes preferred for its effectiveness in longer-term anxiety management. In contrast, hydroxyzine HCl is often chosen for its efficacy in allergy and rash treatments.
Side effects: The side effects of both medications are generally similar and can include dizziness, drowsiness, blurred vision, dry mouth, and headache. However, the intensity of side effects may vary from person to person based on the formulation."
Hope it helps! WC
eman10375
1 day 18 hours ago
Thanks for the information!
Related topics
anxiety, hydroxyzine, side effect, formulation, pharmacokinetics
Further information
- Hydroxyzine uses and safety info
- Hydroxyzine prescribing info & package insert (for Health Professionals)
- Side effects of Hydroxyzine (detailed)
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