Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
ONFI vs BIAXIN
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
GABA-A receptor positive allosteric modulator; increases the frequency of chloride channel opening in response to GABA.
Binds to the 50S ribosomal subunit, inhibiting bacterial protein synthesis by blocking peptide chain elongation.
Treatment of seizures associated with Lennox-Gastaut syndrome,Adjunctive therapy for other seizure types
Acute bacterial exacerbation of chronic bronchitis,Acute maxillary sinusitis,Community-acquired pneumonia,Pharyngitis/tonsillitis,Uncomplicated skin and skin structure infections,Helicobacter pylori eradication (as part of triple or dual therapy),Mycobacterium avium complex prophylaxis and treatment (off-label for some indications)
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.
250-500 mg orally every 12 hours for 7-14 days; extended-release: 1000 mg orally every 24 hours for 7-14 days
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.
Terminal elimination half-life: 3-7 hours (single dose, 250-500 mg); with multiple dosing, half-life may extend to 7-10 hours due to saturable metabolism. Clinical context: Shorter half-life requires twice-daily dosing; extended half-life (via 14-hydroxy metabolite, t1/2 ~11 h) contributes to antibacterial activity.
Hepatic via CYP3A4 and CYP2C19; primary metabolite N-desmethylclobazam is active.
Primarily metabolized by CYP3A4 isoenzyme; clarithromycin undergoes first-pass metabolism to form 14-hydroxyclarithromycin (active metabolite).
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.
Approximately 20-30% of administered dose is excreted unchanged in urine; remainder is hepatically metabolized and excreted in bile and feces (~50% fecal elimination).
Clobazam is approximately 80–90% bound to plasma proteins, primarily albumin.
65-75% bound, primarily to albumin and alpha-1-acid glycoprotein.
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.
Vd: 2.6-3.5 L/kg. Clinical meaning: Large Vd indicates extensive tissue penetration, including lungs, tonsils, and sinuses, exceeding serum concentrations.
Oral bioavailability is nearly complete (>90%). Clobazam is well absorbed after oral administration with only minor first-pass metabolism.
Oral bioavailability: 50-55% (250 mg tablet); may be increased to 60-70% when administered with food. Intravenous: 100%.
No specific GFR-based dose adjustments; use with caution in severe impairment (Cr Cl < 30 m L/min) due to potential for increased sedation.
Cr Cl <30 m L/min: reduce dose by 50%; Cr Cl <10 m L/min: not recommended; no adjustment for Cr Cl >30 m L/min
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.
Child-Pugh Class C: reduce dose by 50% or consider alternative; mild to moderate hepatic impairment: no adjustment
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.
15 mg/kg/day orally divided every 12 hours; maximum 500 mg/day for 10 days; for extended-release, not recommended for children <12 years
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.
No specific dose adjustment; monitor renal function and adjust per renal guidelines; increased risk of QT prolongation
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.
None
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
Increased risk of cardiac arrhythmias, including QT prolongation and torsades de pointes; avoid in patients with known QT prolongation or concurrent use with QT-prolonging drugs.,Potential for hepatotoxicity (elevated liver enzymes, hepatitis); monitor liver function.,Exacerbation of myasthenia gravis symptoms.,Clostridioides difficile-associated diarrhea (CDAD).,Drug interactions via CYP3A4 inhibition (e.g., statins, warfarin, colchicine, and other macrolides).,Pregnancy Category C; avoid use unless no alternative (clarithromycin associated with increased risk of miscarriage and fetal abnormalities in animal studies).
Hypersensitivity to clobazam or any component of formulation,Severe hepatic impairment
Hypersensitivity to clarithromycin, erythromycin, or any macrolide antibiotic.,Concurrent use with pimozide, ergotamine, dihydroergotamine, lovastatin, simvastatin, or colchicine in renal/hepatic impairment.,History of cholestatic jaundice/hepatic dysfunction associated with prior clarithromycin use.,QT prolongation or history of ventricular arrhythmias (including torsades de pointes).,Concurrent use with antiarrhythmics (e.g., quinidine, procainamide, amiodarone) or other QT-prolonging drugs.,Severe hepatic failure or acute porphyria.
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.
Grapefruit and grapefruit juice should be avoided as they inhibit CYP3A4 and may increase clarithromycin levels, raising risk of QT prolongation. High-fat meals may delay absorption but do not significantly alter total exposure. Alcohol is not specifically contraindicated but may increase gastrointestinal irritation; avoid concurrent use of statins (especially simvastatin, lovastatin) due to increased myopathy risk.
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.
FDA Pregnancy Category C. Animal studies have shown fetal harm (cleft palate, skeletal abnormalities) at doses 2-5 times the human clinical dose. No adequate human studies. First trimester: Avoid unless benefit justifies risk. Second and third trimesters: Limited data; use only if clearly needed. Monitor for potential maternal hepatotoxicity.
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.
Clarithromycin is excreted into human breast milk; the milk-to-plasma ratio is approximately 0.25-0.5. Infants exposed via breast milk may experience gastrointestinal disturbances or altered gut flora. Use with caution, especially in infants younger than 6 weeks of age due to risk of hypertrophic pyloric stenosis. Consider temporary discontinuation during therapy if high doses are used.
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.
No specific pharmacokinetic studies have demonstrated a need for dose adjustment during pregnancy. However, pregnancy can increase volume of distribution and renal clearance; empirical dose monitoring is not required. Standard dosing regimens are applied unless hepatic or renal impairment is present.
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.
Biaxin (clarithromycin) is a macrolide antibiotic with activity against atypical pathogens (e.g., Legionella, Mycoplasma, Chlamydia). It is a potent CYP3A4 inhibitor, increasing levels of statins, warfarin, and colchicine. Use caution in myasthenia gravis; may exacerbate weakness. QT prolongation risk: avoid use with other QT-prolonging drugs, correct electrolyte abnormalities. For H. pylori eradication, combine with amoxicillin and a PPI as first-line. Renal dose adjustment required for Cr Cl <30 m L/min.
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.
Take with or without food, but taking with food may reduce stomach upset.,Complete the full course even if you feel better to prevent resistance.,Avoid grapefruit or grapefruit juice while on this medication.,Report any signs of liver problems: yellowing of skin/eyes, dark urine, severe nausea/vomiting.,May cause metallic or bitter taste in the mouth; this is usually temporary.,Tell your doctor if you have myasthenia gravis, as clarithromycin can worsen symptoms.,Avoid driving or operating heavy machinery if you experience dizziness or vision changes.,Use effective contraception if applicable; clarithromycin may reduce oral contraceptive efficacy.
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 ONFI vs BIAXIN, answered by our medical review team.
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.. BIAXIN is a Macrolide Antibiotic that works by Binds to the 50S ribosomal subunit, inhibiting bacterial protein synthesis by blocking peptide chain elongation.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between ONFI and BIAXIN 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 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.. The standard adult dose of BIAXIN is: 250-500 mg orally every 12 hours for 7-14 days; extended-release: 1000 mg orally every 24 hours for 7-14 days. 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 ONFI and BIAXIN 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. 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. BIAXIN is classified as Category C. FDA Pregnancy Category C. Animal studies have shown fetal harm (cleft palate, skeletal abnormalities) at doses 2-5 times the human clinical dose. No adequate human studies. First t. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.