TRIPROLIDINE HYDROCHLORIDE
Clinical safety rating: safe
CNS depressants may enhance sedative effects May cause marked drowsiness and impair mental and physical abilities.
Competitive antagonist of histamine H1 receptors; inhibits histamine-mediated vasodilation, increased capillary permeability, and bronchoconstriction in allergic reactions.
| Metabolism | Primarily hepatic via cytochrome P450 enzymes (CYP3A4); undergoes N-dealkylation and glucuronidation. |
| Excretion | Renal (primarily as metabolites; ~70% recovered in urine within 24 hours, <5% unchanged). Fecal elimination is minor. |
| Half-life | Terminal elimination half-life approximately 3–4 hours in healthy adults; prolonged in renal impairment (up to 12 hours). |
| Protein binding | ~20% bound to serum albumin; low binding affinity. |
| Volume of Distribution | Approximately 2–5 L/kg (wide distribution, including brain). |
| Bioavailability | Oral: ~40–60% due to first-pass metabolism. |
| Onset of Action | Oral: 30–60 minutes. Intramuscular: 10–20 minutes. Intravenous: immediate (within minutes). |
| Duration of Action | Approximately 4–6 hours after oral administration; shorter with IV/IM due to rapid redistribution. |
2.5 mg orally every 4-6 hours as needed; maximum 10 mg per 24 hours.
| Dosage form | SYRUP |
| Renal impairment | CrCl 30-50 mL/min: reduce dose to 1.25 mg every 6 hours; CrCl <30 mL/min: avoid use or extend interval to every 12 hours. |
| Liver impairment | Child-Pugh Class A: no adjustment; Child-Pugh Class B: reduce dose by 50% or extend interval; Child-Pugh Class C: avoid use. |
| Pediatric use | Children 2-6 years: 1.25 mg orally every 4-6 hours (max 5 mg/day); Children 6-12 years: 2.5 mg orally every 4-6 hours (max 7.5 mg/day); based on weight: 0.1 mg/kg/dose every 6 hours (max 2 mg/kg/day). |
| Geriatric use | Start at 1.25 mg orally every 6 hours; increase cautiously due to increased risk of anticholinergic effects, sedation, and cognitive impairment. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
CNS depressants may enhance sedative effects May cause marked drowsiness and impair mental and physical abilities.
| FDA category | Animal |
| Breastfeeding | Triprolidine is excreted into breast milk in small amounts. The M/P ratio is not established. Due to potential for infant sedation, irritability, and decreased milk supply, use during breastfeeding is not recommended, especially in preterm or low-birth-weight infants. |
| Teratogenic Risk | Triprolidine hydrochloride is an antihistamine classified as FDA Pregnancy Category C. Animal studies have shown adverse effects (cleft palate, embryonic resorption) at high doses. There are no adequate human studies. First trimester use should be avoided due to potential teratogenic risk. Second and third trimester use is generally considered low risk but may be associated with uterine irritability and neonatal respiratory depression if used near term. |
■ FDA Black Box Warning
None.
| Common Effects | Sedation |
| Serious Effects |
Hypersensitivity to triprolidine or any components; contraindicated in neonates and preterm infants; concurrent use with MAOIs or within 14 days of MAOI therapy.
| Precautions | May cause drowsiness; avoid driving or operating machinery. Caution in patients with asthma, COPD, increased intraocular pressure, prostatic hyperplasia, urinary retention, or cardiovascular disease. Use with caution in elderly. |
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| Fetal Monitoring | Monitor for maternal sedation, hypotension, and anticholinergic effects. Fetal monitoring is not routinely required but consider ultrasound if first trimester exposure occurred. Monitor neonatal respiratory status if used near delivery. |
| Fertility Effects | In animal studies, high doses of triprolidine have been associated with decreased fertility and implantation failures. Human data are insufficient to determine effect on fertility; potential anticholinergic effects may theoretically affect cervical mucus or implantation. |