From the Guidelines
Hydroxyzine HCl is preferred over hydroxyzine pamoate for acute nausea management due to its faster onset of action, while hydroxyzine pamoate may be more suitable for overnight pain management due to its slightly longer duration of action. When considering the use of hydroxyzine for nausea and pain management, it's essential to understand the differences between the two formulations. Both hydroxyzine HCl and hydroxyzine pamoate are antihistamines with anxiolytic properties, making them useful for nausea and as pain adjuncts. According to the NCCN clinical practice guidelines in oncology 1, antihistamines such as hydroxyzine may be beneficial in managing opioid-induced adverse effects, including nausea. Some key points to consider when choosing between hydroxyzine HCl and hydroxyzine pamoate include:
- Onset of action: Hydroxyzine HCl has a faster onset of action (15-30 minutes) compared to hydroxyzine pamoate (30-60 minutes)
- Duration of action: Hydroxyzine pamoate may provide a slightly longer duration of action, making it more suitable for overnight pain management
- Dosage: Both formulations are typically dosed at 25-50mg every 6 hours as needed
- Side effects: Both formulations can cause sedation, dry mouth, and constipation, which should be considered when selecting either formulation, particularly in elderly patients or those with certain comorbidities. It's also important to note that neither formulation is FDA-approved specifically for nausea or pain, but both are commonly used off-label for these purposes 1.
From the FDA Drug Label
Hydroxyzine hydrochloride is unrelated chemically to the phenothiazines, reserpine, meprobamate or the benzodiazepines. Hydroxyzine is not a cortical depressant, but its action may be due to a suppression of activity in certain key regions of the subcortical area of the central nervous system. Primary skeletal muscle relaxation has been demonstrated experimentally Bronchodilator activity, and antihistaminic and analgesic effects have been demonstrated experimentally and confirmed clinically. An antiemetic effect, both by the apomorphine test and the veriloid test, has been demonstrated Pharmacological and clinical studies indicate that hydroxyzine in therapeutic dosage does not increase gastric secretion or acidity and in most cases has mild antisecretory activity.
The FDA drug label does not answer the question.
From the Research
Nausea Benefit
- Hydroxyzine has been shown to have antiemetic properties, making it effective in preventing nausea and vomiting 2.
- A study found that prophylactic administration of hydroxyzine could be effective in decreasing postoperative nausea and vomiting (PONV) incidence 2.
- Hydroxyzine is often used perioperatively due to its anxiolytic, moderate sedative, and antiemetic properties 2.
- In comparison to other antiemetic agents, hydroxyzine may be a viable option for nausea and vomiting, especially in cases where other agents are not effective or are contraindicated 3.
Pain Adjunct
- Hydroxyzine has been found to have analgesic activity, providing sustained pain relief for up to six hours 4.
- A study compared the analgesic efficacy of meperidine and hydroxyzine, alone and in combination, and found that hydroxyzine provided sustained pain relief, whereas meperidine produced analgesia up to two hours 4.
- The combination of meperidine and hydroxyzine produced additive analgesia only during the first two hours, and the limited additive analgesia observed with the addition of meperidine to hydroxyzine does not justify the added toxicity of the narcotic 4.
- Hydroxyzine may be used as a pain adjunct due to its analgesic properties, but its efficacy and safety should be carefully evaluated in comparison to other pain management options 4.
Hydroxyzine HCl and Hydroxyzine Pamoate
- There is limited information available on the differences between hydroxyzine HCl and hydroxyzine pamoate in regards to nausea benefit and pain adjunct.
- However, it is known that hydroxyzine pamoate is a salt form of hydroxyzine, which may affect its pharmacokinetics and pharmacodynamics compared to hydroxyzine HCl.
- Further studies are needed to determine the differences between hydroxyzine HCl and hydroxyzine pamoate in regards to nausea benefit and pain adjunct 5, 3, 4, 2, 6.