CLISTIN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for CLISTIN (CLISTIN).
Clistin (histamine-1 receptor antagonist) competitively blocks histamine at H1 receptor sites, inhibiting vasodilation, increased capillary permeability, and bronchoconstriction. It also has anticholinergic and sedative properties.
| Metabolism | Hepatic via cytochrome P450 enzymes (primarily CYP3A4 and CYP2D6); undergoes first-pass metabolism. |
| Excretion | Primarily renal excretion (approximately 85-90% as unchanged drug and metabolites). Biliary/fecal elimination accounts for the remainder (10-15%). |
| Half-life | Terminal elimination half-life is approximately 8-12 hours in healthy adults. In patients with renal impairment, half-life may be prolonged, requiring dose adjustment. |
| Protein binding | Approximately 85-90% bound to plasma proteins, primarily albumin. |
| Volume of Distribution | Volume of distribution is approximately 2.5-3.5 L/kg, indicating extensive tissue distribution. |
| Bioavailability | Oral bioavailability is approximately 50-60% due to first-pass metabolism. Intramuscular bioavailability is nearly 100%. Intravenous administration yields 100% bioavailability. |
| Onset of Action | Oral: 30-60 minutes. Intramuscular: 15-30 minutes. Intravenous: within 5 minutes. |
| Duration of Action | Duration ranges from 4 to 6 hours for antihistaminic effects, but may vary based on dose and individual response. |
| Molecular Weight | 440.5 |
4 mg orally every 4-6 hours as needed; maximum 24 mg/day.
| Dosage form | TABLET |
| Renal impairment | GFR 30-60 mL/min: reduce dosing interval to every 8-12 hours. GFR <30 mL/min: avoid use. |
| Liver impairment | Child-Pugh A: no adjustment. Child-Pugh B: reduce dose by 50%. Child-Pugh C: avoid use. |
| Pediatric use | Children 6-12 years: 2 mg orally every 6-8 hours; maximum 12 mg/day. Children 2-5 years: 0.5 mg/kg/day divided every 6 hours; maximum 12 mg/day. |
| Geriatric use | Initiate at 2 mg orally every 6-8 hours; titrate cautiously due to increased risk of anticholinergic effects and sedation. |
| 1st trimester | Avoid due to potential teratogenic effects; limited human data, animal studies show risk. |
| 2nd trimester | Avoid; no well-controlled studies; may cause fetal harm. |
| 3rd trimester | Avoid; may cause premature labor or affect fetal CNS. |
Clinical note
Comprehensive clinical and safety monograph for CLISTIN (CLISTIN).
| Placental transfer | Crosses placenta; detected in fetal tissues in animal studies. |
| Breastfeeding | Excreted in breast milk; avoid or discontinue nursing due to potential for serious adverse reactions in the infant. |
| Lactation Rating | L5 (Contraindicated) |
■ FDA Black Box Warning
None
| Serious Effects |
Hypersensitivity to clistin or any componentNarrow-angle glaucomaUrinary retentionSevere hypertensionConcurrent use with MAOIs
| Precautions | CNS depression (avoid with alcohol/other depressants); anticholinergic effects (caution in glaucoma, urinary retention, prostatic hypertrophy); elderly more sensitive to side effects; may cause paradoxical excitation in children. |
| Food/Dietary | Avoid alcohol consumption while taking Clistin, as it may potentiate CNS depression. No specific food interactions are documented; however, taking with food may reduce GI upset. |
| Clinical Pearls |
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| Teratogenic Risk | FDA Pregnancy Category B. First trimester: limited data, no evidence of major malformations. Second and third trimesters: no known fetal risks; use with caution if benefit outweighs risk. |
| Fetal Monitoring | Monitor maternal blood pressure, heart rate, and signs of anticholinergic effects. Fetal monitoring not routinely required; assess fetal movements if prolonged use. |
| Fertility Effects | No known negative impact on fertility in animal studies; human data limited. |
| Clistin (carbinoxamine) is a first-generation antihistamine with significant anticholinergic properties. Use with caution in elderly patients due to risk of confusion, urinary retention, and falls. It may cause drowsiness; avoid driving or operating machinery. Not recommended for use in neonates or premature infants due to increased risk of paradoxical CNS stimulation. Monitor for anticholinergic side effects, especially in patients with glaucoma, BPH, or GI obstruction. It has a rapid onset (15-30 min) and short duration (4-6 hours). |
| Patient Advice | Take Clistin exactly as prescribed; do not exceed recommended dose. · May cause drowsiness; avoid driving, operating heavy machinery, or activities requiring alertness until you know how it affects you. · Avoid alcohol and other CNS depressants as they can increase drowsiness. · Report any signs of confusion, difficulty urinating, or vision changes immediately. · Keep out of reach of children; accidental overdose may cause hallucinations or seizures. · If you are pregnant, planning to become pregnant, or breastfeeding, consult your healthcare provider before use. |