TRIPELENNAMINE HYDROCHLORIDE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for TRIPELENNAMINE HYDROCHLORIDE (TRIPELENNAMINE HYDROCHLORIDE).
Tripelennamine hydrochloride is a first-generation antihistamine that competitively antagonizes histamine at H1 receptor sites, thereby preventing histamine-mediated effects such as vasodilation, increased vascular permeability, and bronchoconstriction. It also possesses anticholinergic and sedative properties.
| Metabolism | Primarily hepatic via cytochrome P450 enzymes, including CYP2D6 and CYP3A4; undergoes N-demethylation and other oxidative pathways. |
| Excretion | Primarily renal, with approximately 30-50% of the dose excreted unchanged in urine. Biliary/fecal excretion accounts for less than 20%. |
| Half-life | Terminal elimination half-life is approximately 4-6 hours in healthy adults. In patients with hepatic impairment, the half-life may be prolonged to 10-12 hours. |
| Protein binding | Approximately 90-95% bound to plasma proteins, primarily albumin. |
| Volume of Distribution | Approximately 3-4 L/kg, indicating extensive tissue distribution with higher concentrations in lungs, liver, and spleen compared to plasma. |
| Bioavailability | Oral: approximately 30-40% due to first-pass metabolism. Intramuscular: near 100%. |
| Onset of Action | Oral: 30-60 minutes. Intramuscular: 15-30 minutes. Intravenous: within minutes. |
| Duration of Action | 4-6 hours for antihistamine effects; may be shorter for antipruritic effects. Clinical duration may be prolonged in hepatic impairment. |
| Molecular Weight | 289.8 |
50-100 mg orally every 4-6 hours as needed; maximum 600 mg/day.
| Dosage form | TABLET |
| Renal impairment | GFR 10-50 mL/min: administer every 6-8 hours; GFR <10 mL/min: administer every 8-12 hours. |
| Liver impairment | Child-Pugh Class A: no adjustment; Child-Pugh Class B: reduce dose by 50%; Child-Pugh Class C: avoid use. |
| Pediatric use | Children 2-6 years: 5 mg/kg/day in divided doses every 4-6 hours; maximum 30 mg/day. Children 6-12 years: 5 mg/kg/day in divided doses every 4-6 hours; maximum 60 mg/day. |
| Geriatric use | Start at lowest effective dose (25 mg every 6-8 hours); increase cautiously due to increased risk of anticholinergic effects and falls. |
| 1st trimester | Avoid. Antihistamines with sedative properties may be associated with increased risk of congenital malformations, though data are limited. Use only if clearly needed. |
| 2nd trimester | Caution. Use lowest effective dose for shortest duration. Limited data suggest no major teratogenic risk, but potential for neonatal sedation. |
| 3rd trimester | Avoid near term. May cause uterine irritability, premature contractions, or neonatal respiratory depression and withdrawal symptoms. |
Clinical note
Comprehensive clinical and safety monograph for TRIPELENNAMINE HYDROCHLORIDE (TRIPELENNAMINE HYDROCHLORIDE).
| Placental transfer | Crosses placenta; extent unknown but likely due to molecular weight and lipophilicity. |
| Breastfeeding | Excreted into breast milk in small amounts; however, may cause sedation, irritability, or decreased feeding in infants. Use with caution, especially in neonates or preterm infants. Monitor infant for drowsiness. |
■ FDA Black Box Warning
None
| Serious Effects |
Hypersensitivity to tripelennamine or any componentConcurrent use with monoamine oxidase inhibitorsNarrow-angle glaucomaUrinary retentionSevere liver disease
| Precautions | Anticholinergic effects: Use with caution in patients with asthma, increased intraocular pressure, hyperthyroidism, cardiovascular disease, or hypertension., Sedation: May impair mental and physical abilities; caution when driving or operating machinery., Respiratory depression: Avoid use in neonates and patients with lower respiratory tract disease., Drug interactions: Potentiates CNS depressants (alcohol, sedatives, tranquilizers) and anticholinergics., Geriatric use: More sensitive to anticholinergic and sedative effects; increased risk of confusion and falls. |
| Food/Dietary | Alcohol may potentiate CNS depression (sedation, dizziness). Avoid grapefruit juice as it may inhibit metabolism via CYP450 enzymes, increasing drug levels and side effects. No other significant food interactions. |
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| Lactation Rating | L3 (Moderately Safe) |
| Teratogenic Risk | Tripelennamine hydrochloride is an H1 antihistamine classified as FDA Pregnancy Category B. Animal studies have not demonstrated fetal risk, but there are no adequate and well-controlled studies in pregnant women. First trimester exposure is not associated with major congenital malformations; however, antihistamines should be used with caution due to potential maternal drowsiness and hypotension. In the second and third trimesters, use near term may cause neonatal respiratory depression, irritability, or paradoxical excitation if used in high doses. |
| Fetal Monitoring | Monitor maternal blood pressure and CNS effects (sedation, dizziness). Assess fetal heart rate and uterine activity if used in labor. Monitor neonate for respiratory depression, hypotonia, or irritability if used near term. |
| Fertility Effects | No significant adverse effects on fertility have been reported in animal studies. In humans, antihistamines may cause anticholinergic effects (e.g., vaginal dryness) that could theoretically affect conception, but no direct evidence of impaired fertility exists. |
| Clinical Pearls | Tripelennamine is a first-generation antihistamine (H1 antagonist) with significant anticholinergic and sedative properties. It penetrates the CNS, causing drowsiness, and is used for allergic reactions, motion sickness, and as an antipruritic. Monitor for paradoxical excitation in children and the elderly. Avoid use in patients with narrow-angle glaucoma, prostatic hypertrophy, or urinary retention. It has weak local anesthetic effects; intravenous use is contraindicated due to risk of seizure and hypotension. |
| Patient Advice | Take exactly as prescribed; do not exceed recommended dose. · May cause severe drowsiness; avoid driving or operating machinery until you know how you react. · Avoid alcohol and other CNS depressants like sedatives or tranquilizers. · Do not use in children unless directed by a doctor. · Contact your doctor if you experience rapid heartbeat, confusion, or difficulty urinating. |