Short answer: they’re the same drug (hydroxyzine) but in two different salt forms. The salt can change how quickly it starts working and how long it lasts.
Hydroxyzine pam (hydroxyzine pamoate) vs hydroxyzine HCl (hydroxyzine hydrochloride)
- What they are
- Hydroxyzine pam/oate = hydroxyzine with the pamoate counterion.
- Hydroxyzine HCl = hydroxyzine with chloride as the counterion.
- Both are antihistamines with sedative, anti-anxiety, and anti-itch (antipruritic) effects.
- How they differ in use and effect
- Onset and duration
- HCl: generally faster onset, shorter duration.
- Pamoate: slower onset, longer duration (often described as more “long-acting” or extended-acting).
- Common indications
- Both can treat anxiety and pruritus.
- HCl is also commonly used for sedation and, in some settings, antiemetic effects.
- Pamoate is often used for anxiety and pruritus and may be preferred when a longer-lasting effect is desired (e.g., less frequent dosing in some regimens).
- Brand examples in the U.S.
- Hydroxyzine HCl: Atarax
- Hydroxyzine pamoate: Vistaril
- Dosing notes
- The milligram strength on the label reflects the salt form, not just the active hydroxyzine base, so you can’t directly swap mg between forms without a doctor’s guidance.
- Dosing is tailored to the condition, patient factors, and response. Always follow the label or your prescriber’s instructions.
- Side effects and safety (for both forms)
- Common: drowsiness, dry mouth, dizziness, headache.
- Anticholinergic effects (dry mouth, blurred vision, constipation) and CNS depressant effects can be more pronounced with higher doses or with other sedatives/alcohol.
- Cautions: use with care in elderly, in glaucoma, urinary retention, or certain other medical conditions; avoid alcohol and other sedatives unless advised by a clinician.
- Quick take
- If you’re choosing between them, the form is usually chosen by your clinician based on how quickly you need relief and how long you want it to last.
- In many cases, either form will help with anxiety or itching, but they are not always interchangeable dose-for-dose.
- Don’t switch forms or adjust doses without your clinician’s guidance.
If you can share why you’re asking (for itching vs anxiety, any other meds you’re taking, how soon you need relief, etc.), I can tailor the comparison a bit more and point out what your doctor or pharmacist might consider when choosing between the two.