HY-PAM "25"
Clinical safety rating
cautionComprehensive clinical and safety monograph for HY-PAM "25" (HY-PAM "25").
Hydroxyzine pamoate is a piperazine antihistamine that acts as a histamine H1-receptor antagonist, thereby suppressing histamine-mediated responses in the skin and mucous membranes. Additionally, it exhibits anxiolytic and sedative properties through central nervous system depression via inhibition of subcortical regions.
| Metabolism | Primarily hepatic via CYP3A4 and CYP2D6 isoenzymes; major metabolite is cetirizine. |
| Excretion | Primarily renal (60-70% unchanged drug), with 30-40% biliary/fecal elimination as metabolites. |
| Half-life | Terminal elimination half-life 6-8 hours in healthy adults; prolonged to 12-18 hours in renal impairment (CrCl <30 mL/min) and in elderly patients. |
| Protein binding | 95-98% bound to albumin and alpha-1-acid glycoprotein. |
| Volume of Distribution | 0.2-0.3 L/kg, indicating primarily plasma and extracellular fluid distribution. |
| Bioavailability | Oral: 60-70% (due to first-pass metabolism); Rectal: 80-90%; Intramuscular: 100%. |
| Onset of Action | Intravenous: 30-60 seconds; Oral: 30-60 minutes. |
| Duration of Action | Intravenous: 15-30 minutes (dose-dependent); Oral: 3-6 hours (sustained release forms up to 12 hours). |
| Molecular Weight | 447.9 |
25 mg orally once daily, preferably at bedtime, for short-term treatment of insomnia.
| Dosage form | CAPSULE |
| Renal impairment | No dose adjustment required for mild to moderate renal impairment (CrCl ≥30 mL/min). For severe renal impairment (CrCl <30 mL/min), use with caution; no specific dose recommendation available. |
| Liver impairment | For Child-Pugh Class A or B, dose reduction to 12.5 mg daily may be considered due to increased exposure; avoid use in Child-Pugh Class C (severe hepatic impairment). |
| Pediatric use | Not established; contraindicated in pediatric patients due to lack of safety and efficacy data. |
| Geriatric use | Start at 12.5 mg daily; maximum dose 25 mg daily due to increased sensitivity and risk of falls, cognitive impairment, and adverse effects. |
| 1st trimester | Hydroxyzine pamoate is generally avoided during the first trimester due to potential teratogenic effects observed in animal studies and limited human data. Use only if clearly needed and benefit outweighs risk. |
| 2nd trimester | Use with caution in the second trimester; no well-controlled studies in pregnant women. Avoid prolonged or high-dose therapy. |
| 3rd trimester | May cause neonatal respiratory depression, hypotonia, or withdrawal if used near term. Avoid in late pregnancy, especially during labor. |
Clinical note
Comprehensive clinical and safety monograph for HY-PAM "25" (HY-PAM "25").
| Placental transfer | Hydroxyzine crosses the placenta; fetal concentrations may be similar to maternal. Data limited but transfer documented in animal studies. |
| Breastfeeding | Hydroxyzine is excreted into breast milk in small amounts. Potential for sedation or irritability in the infant. Avoid or use caution; monitor infant for drowsiness. Consider alternative agents if possible. |
| Lactation Rating | L3 (Moderately Safe) |
| Teratogenic Risk | HY-PAM 25 is a benzodiazepine. First trimester: Data suggest an increased risk of oral clefts (approximately 0.6% vs 0.4% background). Second trimester: Possible risk of other malformations, but data are limited. Third trimester: Chronic use may cause neonatal withdrawal, floppy infant syndrome (hypotonia, lethargy, feeding difficulties), and respiratory depression at delivery. |
| Fetal Monitoring | Monitor maternal sedation, respiratory rate, and blood pressure. Fetal: Ultrasound for growth (if prolonged use), assess for signs of withdrawal or floppy infant syndrome at birth. Neonatal: Apgar scores, respiratory effort, and feeding. Consider therapeutic drug monitoring if toxicity suspected. |
| Fertility Effects | No significant impairment in fertility reported in humans. Animal studies show high doses may affect estrous cycle or spermatogenesis, but clinical relevance is minimal. |
■ FDA Black Box Warning
None
| Serious Effects |
Hypersensitivity to hydroxyzine or any componentEarly pregnancy (first trimester) except in dire needPorphyriaUse in neonates or premature infants (injection form contains benzyl alcohol)
| Precautions | May cause QT prolongation, especially in patients with risk factors, Use with caution in patients with narrow-angle glaucoma, prostatic hypertrophy, or urinary retention, Central nervous system depressant effects may impair mental or physical abilities, Avoid concurrent use with alcohol or other CNS depressants, Use with caution in elderly patients due to increased sensitivity and anticholinergic effects |
| Food/Dietary | No significant food interactions known. |
| Clinical Pearls | HY-PAM '25' is a compounded topical formulation containing hydrocortisone 2.5%, pramoxine 1%, and aluminum acetate 0.25%. Use for acute inflammatory dermatoses with pruritus and exudation. Avoid prolonged use on intertriginous areas. Discontinue if signs of skin atrophy or secondary infection develop. |
| Patient Advice | Apply a thin layer to affected areas 3-4 times daily. · Do not use on broken skin, deep wounds, or infected skin without medical guidance. · Avoid contact with eyes and mucous membranes. · Do not cover with bandages or dressings unless directed by your doctor. · Report any worsening of rash, burning, or signs of skin thinning. · Do not use for more than 2 weeks unless directed by your doctor. |
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