Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
ATIVAN vs ONFI
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Benzodiazepine that potentiates GABA-A receptor activity by increasing the frequency of chloride channel opening, leading to neuronal hyperpolarization and inhibition.
GABA-A receptor positive allosteric modulator; increases the frequency of chloride channel opening in response to GABA.
Anxiety disorders,Short-term relief of anxiety symptoms,Status epilepticus (IV),Preanesthetic medication (IM/IV)
Treatment of seizures associated with Lennox-Gastaut syndrome,Adjunctive therapy for other seizure types
2-3 mg orally divided 2-3 times daily; up to 10 mg/day. IV: 2 mg slow IV push, may repeat in 1-2 hours; max 10 mg/day. IM: 0.05 mg/kg (max 4 mg) 2-4 hours before procedure.
Initial: 10 mg orally twice daily; may increase by 10 mg/day after 1 week to maintenance of 20–40 mg/day in two divided doses. Maximum: 60 mg/day.
Terminal elimination half-life is 12–18 hours (mean ~14 h). In elderly, hepatic impairment, or obesity, half-life may be prolonged up to 30 hours.
The terminal elimination half-life of clobazam is 36–42 hours. The active metabolite N-desmethylclobazam has a half-life of 71–82 hours. The long half-life permits once-daily dosing but also leads to slow accumulation; steady-state is achieved after 2–3 weeks.
Hepatic via glucuronidation (UGT2B15, UGT2B7); major metabolite is lorazepam glucuronide (inactive).
Hepatic via CYP3A4 and CYP2C19; primary metabolite N-desmethylclobazam is active.
Renal: lorazepam is primarily excreted as inactive glucuronide conjugates; <1% is excreted unchanged. Total: ~95% excreted in urine, ~5% in feces.
Clobazam (ONFI) undergoes extensive hepatic metabolism. Approximately 82% of the dose is eliminated in urine (as unchanged drug and metabolites) and about 11% in feces. Unchanged clobazam accounts for <1% of urinary excretion. The major metabolite, N-desmethylclobazam, is excreted primarily renally.
91% ± 2% bound to albumin. Binding is linear over therapeutic concentrations and not saturable.
Clobazam is approximately 80–90% bound to plasma proteins, primarily albumin.
1.3 ± 0.2 L/kg. Vd increases with obesity, hepatic cirrhosis, and in elderly patients, indicating extensive tissue distribution.
The apparent volume of distribution is approximately 100 L (range 77–120 L), or roughly 1.4 L/kg. This large Vd indicates extensive tissue distribution and accumulation in fatty tissues.
Oral: 90% (range 80–100%) with first-pass metabolism negligible; Sublingual: ~90%; Intramuscular: 100% (absolute bioavailability).
Oral bioavailability is nearly complete (>90%). Clobazam is well absorbed after oral administration with only minor first-pass metabolism.
Cr Cl 10-50 m L/min: reduce dose by 50% or increase interval; Cr Cl <10 m L/min: avoid or reduce dose by 50-75% with caution.
No specific GFR-based dose adjustments; use with caution in severe impairment (Cr Cl < 30 m L/min) due to potential for increased sedation.
Child-Pugh A: no adjustment; Child-Pugh B: reduce dose by 50%; Child-Pugh C: avoid or reduce dose by 50-75% with monitoring.
Mild to moderate (Child-Pugh A/B): Initial 5 mg orally twice daily; may increase by 5 mg/day after 1 week to maximum 20 mg/day. Severe (Child-Pugh C): Not recommended.
Children ≥6 months: 0.02-0.05 mg/kg/dose IV/IM (max 2 mg) for status epilepticus; PO: 0.05-0.1 mg/kg/dose (max 2 mg) 2-4 times daily.
Clobazam (ONFI) for seizures: Age 2 to <6 years, body weight ≥12.5 kg: Initial 5 mg orally once daily; titrate to maintenance 5 mg twice daily. Age ≥6 years: Weight ≤30 kg: Initial 5 mg once daily; titrate to 5 mg twice daily (max 20 mg/day). Weight >30 kg: same as adult dosing. Administer with food.
Initiate at 0.5-1 mg orally daily in divided doses; increase slowly; max 2 mg/day. IV/IM: 0.5-1 mg initial; avoid doses >2 mg due to increased sedation risk.
Elderly (≥65 years): Initial 5 mg orally twice daily; increase slowly to lowest effective maintenance due to increased sensitivity and risk of falls. Avoid doses above 20 mg/day unless clearly necessary.
Concomitant use of benzodiazepines and opioids may result in profound sedation, respiratory depression, coma, and death.
Concomitant use with opioids may result in profound sedation, respiratory depression, coma, and death. Reserve concomitant use for patients for whom alternative treatment options are inadequate.
Respiratory depression risk,Dependence and withdrawal syndrome,Abuse potential,Paradoxical reactions (hyperactivity, aggression),Use with caution in hepatic impairment,Elderly at increased risk for sedation and falls
Risk of respiratory depression, especially with opioids,Sedation and somnolence,Risk of abuse and dependence,Withdrawal seizures on abrupt discontinuation,Increased risk of suicidal thoughts or behavior
Hypersensitivity to lorazepam or any benzodiazepine,Acute narrow-angle glaucoma,Severe respiratory insufficiency,Myasthenia gravis,Concurrent use with opioids (absolute unless alternative unavailable)
Hypersensitivity to clobazam or any component of formulation,Severe hepatic impairment
No specific food interactions. However, grapefruit juice may increase lorazepam levels (minor interaction). Avoid excessive caffeine as it may reduce sedative effects.
Avoid grapefruit and grapefruit juice as they may increase clobazam levels. No other significant food interactions are known. CNS depressant effects may be potentiated by alcohol.
First trimester: Increased risk of oral clefts (odds ratio 1.5–2.0); second and third trimesters: Risk of hypotonia, respiratory depression, and withdrawal symptoms in neonate; avoid in first trimester if possible; use lowest effective dose.
Pregnancy Category C. First trimester: increased risk of major malformations including cleft lip/palate (OR 2.0-3.0); second/third trimester: risk of neonatal withdrawal, hypotonia, poor feeding, respiratory depression, and hypothermia; consistent exposure may cause floppy infant syndrome. Late pregnancy exposure linked to neonatal benzodiazepine withdrawal syndrome.
Enters breast milk; M/P ratio approximately 0.2–0.5; avoid or use with caution due to infant sedation and feeding difficulties; monitor for drowsiness and weight gain.
Clobazam is excreted into breast milk; M/P ratio approximately 0.5-0.6. Accumulation possible in neonates; monitor for sedation, poor feeding, apnea. Avoid if infant has impaired hepatic function or low birth weight. American Academy of Pediatrics recommends caution; use lowest effective maternal dose.
Increased clearance and volume of distribution in pregnancy may necessitate dose increase; monitor clinical response; use lowest effective dose; avoid late third trimester if possible.
Increased clearance during pregnancy (CYP3A4 induction); plasma concentrations may decrease by 30-50% in third trimester. Dose adjustments often required: monitor therapeutic response and consider dose increase by 50-100% in late pregnancy; postpartum reduce to prepregnancy dose over 1-2 weeks to avoid toxicity.
ATIVAN (lorazepam) is a benzodiazepine with intermediate onset and duration; useful for status epilepticus (IV) and preoperative anxiolysis. Monitor for respiratory depression, especially when combined with opioids. Not ideal for long-term anxiety due to tolerance and dependence risk. Use with caution in elderly (increased fall risk).
ONFI (clobazam) is a benzodiazepine indicated for seizures associated with Lennox-Gastaut syndrome. Titrate slowly to minimize sedation. Monitor for withdrawal symptoms upon discontinuation; taper over several weeks. Not recommended for use in patients with severe hepatic impairment (Child-Pugh C). For patients on other CNS depressants, consider dose reduction. Clobazam's active metabolite, N-desmethylclobazam, has a long half-life (36-46 hours) and can accumulate, especially in poor CYP2C19 metabolizers. In such patients, consider lower doses and monitor for excessive sedation.
Do not drive or operate machinery until you know how this medication affects you.,Avoid alcohol and other CNS depressants while taking ATIVAN.,Take exactly as prescribed; do not increase dose or stop abruptly without consulting your doctor.,May cause drowsiness, dizziness, or blurred vision.,Report any unusual mood changes, confusion, or respiratory difficulty.,This medication can be habit-forming; prolonged use may lead to dependence.,Notify your doctor if you are pregnant, planning to become pregnant, or breastfeeding.
Take ONFI exactly as prescribed; do not stop suddenly as withdrawal seizures may occur.,Avoid alcohol and other sedatives while taking this medication due to increased risk of drowsiness and respiratory depression.,Report any unusual mood changes, depression, or suicidal thoughts to your healthcare provider.,Do not drive or operate heavy machinery until you know how ONFI affects you, as it can cause dizziness and drowsiness.,If you are pregnant, planning to become pregnant, or breastfeeding, discuss with your doctor before using ONFI.,Store at room temperature, away from moisture and heat.
No interactions on record
No interactions on record
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about ATIVAN vs ONFI, answered by our medical review team.
ATIVAN is a Benzodiazepine that works by Benzodiazepine that potentiates GABA-A receptor activity by increasing the frequency of chloride channel opening, leading to neuronal hyperpolarization and inhibition.. ONFI is a Benzodiazepine Anticonvulsant that works by GABA-A receptor positive allosteric modulator; increases the frequency of chloride channel opening in response to GABA.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between ATIVAN and ONFI depend on the specific clinical indication. These are agents from distinct pharmacological classes and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.
The standard adult dose of ATIVAN is: 2-3 mg orally divided 2-3 times daily; up to 10 mg/day. IV: 2 mg slow IV push, may repeat in 1-2 hours; max 10 mg/day. IM: 0.05 mg/kg (max 4 mg) 2-4 hours before procedure.. The standard adult dose of ONFI is: Initial: 10 mg orally twice daily; may increase by 10 mg/day after 1 week to maintenance of 20–40 mg/day in two divided doses. Maximum: 60 mg/day.. Dosing should always be individualized based on indication, renal and hepatic function, age, and other patient factors.
No direct drug-drug interaction has been formally documented between ATIVAN and ONFI in current clinical databases. However, individual patient risk factors including other medications, organ function, and comorbidities should always be evaluated by a qualified healthcare provider.
The maternal-fetal safety profiles differ. ATIVAN is classified as Category C. First trimester: Increased risk of oral clefts (odds ratio 1.5–2.0); second and third trimesters: Risk of hypotonia, respiratory depression, and withdrawal symptoms in neonate; avo. ONFI is classified as Category C. Pregnancy Category C. First trimester: increased risk of major malformations including cleft lip/palate (OR 2.0-3.0); second/third trimester: risk of neonatal withdrawal, hypotonia. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.