CLISTIN

Clinical safety rating: caution

Comprehensive clinical and safety monograph for CLISTIN (CLISTIN).

How it works

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.

What the body does with it

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.

Classification & Brands

Dosing & administration

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.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for CLISTIN (CLISTIN).

Breastfeeding	Excreted in breast milk in small amounts; M/P ratio not established. Considered compatible with breastfeeding; monitor infant for drowsiness or irritability.
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

Warnings & precautions

■ FDA Black Box Warning

None

Side Effect Profile

Serious Effects

Absolute Contraindications

Hypersensitivity to antihistamines; narrow-angle glaucoma; symptomatic prostatic hypertrophy; bladder neck obstruction; concurrent use with MAO inhibitors.

Clinical Precautions

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.

Clinical Tips & Counseling

Drug interactions

Loading safety data…

CLISTIN

Clinical safety rating: caution

Comprehensive clinical and safety monograph for CLISTIN (CLISTIN).

How it works

What the body does with it

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.

Classification & Brands

Dosing & administration

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.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for CLISTIN (CLISTIN).

Breastfeeding	Excreted in breast milk in small amounts; M/P ratio not established. Considered compatible with breastfeeding; monitor infant for drowsiness or irritability.
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

Warnings & precautions

■ FDA Black Box Warning

None

Side Effect Profile

Serious Effects

Absolute Contraindications

Hypersensitivity to antihistamines; narrow-angle glaucoma; symptomatic prostatic hypertrophy; bladder neck obstruction; concurrent use with MAO inhibitors.