Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
ONFI vs AMILORIDE HYDROCHLORIDE AND HYDROCHLOROTHIAZIDE
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.
Amiloride is a potassium-sparing diuretic that blocks epithelial sodium channels (ENa C) in the distal convoluted tubule and collecting duct, inhibiting sodium reabsorption and reducing potassium excretion. Hydrochlorothiazide is a thiazide diuretic that inhibits the sodium-chloride cotransporter (NCC) in the distal convoluted tubule, increasing sodium, chloride, and water excretion.
Treatment of seizures associated with Lennox-Gastaut syndrome,Adjunctive therapy for other seizure types
Hypertension,Edema associated with congestive heart failure, cirrhosis, or nephrotic syndrome,Hypokalemia prevention or correction in patients on diuretics
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.
One tablet (amiloride 5 mg/hydrochlorothiazide 50 mg) orally once daily initially, increased if needed to twice daily. Maximum dose: amiloride 10 mg/hydrochlorothiazide 100 mg daily.
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.
Amiloride: 6-9 hours (prolonged in renal impairment); Hydrochlorothiazide: 6-15 hours (prolonged in renal impairment, heart failure).
Hepatic via CYP3A4 and CYP2C19; primary metabolite N-desmethylclobazam is active.
Amiloride is not metabolized; excreted unchanged in urine. Hydrochlorothiazide is not extensively metabolized; small amounts are metabolized hepatically via CYP450 enzymes, but the exact pathways are not well defined.
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.
Amiloride: 50% unchanged in urine, 40% in feces (biliary); Hydrochlorothiazide: >95% unchanged in urine.
Clobazam is approximately 80–90% bound to plasma proteins, primarily albumin.
Amiloride: ~23%; Hydrochlorothiazide: 40-68% (primarily to albumin).
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.
Amiloride: 350-440 L (5-6 L/kg in 70 kg adult), indicating extensive tissue distribution; Hydrochlorothiazide: 3-5 L/kg, distributes into extracellular space.
Oral bioavailability is nearly complete (>90%). Clobazam is well absorbed after oral administration with only minor first-pass metabolism.
Amiloride: 50-80% (oral); Hydrochlorothiazide: 60-80% (oral).
No specific GFR-based dose adjustments; use with caution in severe impairment (Cr Cl < 30 m L/min) due to potential for increased sedation.
Contraindicated if GFR <30 m L/min or serum creatinine >2.5 mg/d L. For GFR 30-50 m L/min: use with caution and monitor electrolytes; avoid if further renal impairment.
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 A: no adjustment; Class B: reduce dose or use alternative; Class C: avoid use (risk of hepatic encephalopathy).
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.
Not established; safety and efficacy not determined in children.
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.
Start at lowest dose, monitor electrolytes and renal function; increased sensitivity to hypotension and electrolyte disturbances; avoid if creatinine clearance <30 m L/min.
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
Hyperkalemia risk, especially with renal impairment, diabetes, or concomitant use of potassium supplements, ACE inhibitors, or aldosterone antagonists,Electrolyte imbalances (hyponatremia, hypomagnesemia, hypochloremia),Azotemia and renal impairment,Sulfonamide hypersensitivity cross-reactivity (hydrochlorothiazide is a sulfonamide derivative),Acute angle-closure glaucoma (rare with thiazides),Monitor serum electrolytes, renal function, and blood glucose
Hypersensitivity to clobazam or any component of formulation,Severe hepatic impairment
Anuria,Acute or chronic renal insufficiency (creatinine clearance <10 m L/min),Hyperkalemia (serum potassium >5.5 m Eq/L),Concomitant use of other potassium-sparing diuretics, potassium supplements, or amiloride-containing drugs,Hypersensitivity to amiloride, hydrochlorothiazide, or sulfonamide-derived drugs
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.
Avoid high-potassium foods (e.g., bananas, oranges, spinach, potatoes) in large amounts. Limit salt intake. Grapefruit juice may increase hydrochlorothiazide absorption; avoid concurrent consumption.
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.
First trimester: Limited data; thiazide use associated with possible increased risk of congenital anomalies including neural tube defects and limb reduction defects, but evidence is inconclusive. Second and third trimesters: Hydrochlorothiazide may cause fetal/neonatal electrolyte disturbances, jaundice, and thrombocytopenia. Amiloride has not been associated with major teratogenic effects in animal studies, but human data are inadequate. Overall risk is moderate; avoid in pregnancy if possible, especially for treatment of hypertension, as alternatives exist.
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.
Hydrochlorothiazide is excreted into breast milk in low amounts (M/P ratio approximately 1.5); amiloride is also excreted in animal milk but human data lacking. Potential for neonatal electrolyte imbalance and thrombocytopenia from thiazide. Use during breastfeeding is not recommended unless essential. Monitor infant for signs of dehydration and electrolyte disturbances.
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 dose adjustments recommended for pregnancy due to lack of pharmacokinetic studies; however, increased renal clearance during pregnancy may reduce diuretic efficacy. Caution with hypovolemia and electrolyte disturbances. Use lowest effective dose and consider alternative agents for hypertension in pregnancy (e.g., methyldopa, labetalol).
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.
Amiloride is potassium-sparing; hydrochlorothiazide causes potassium loss. The combination offsets hypokalemia risk. Monitor serum potassium, especially in renal impairment or with NSAIDs. Avoid in anuria or severe renal disease. Onset of diuresis: 2 hours; peak effect: 6-12 hours; duration: 24 hours.
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 this medication exactly as prescribed, usually once daily in the morning to avoid nighttime urination.,This drug increases urine output and may cause dizziness or lightheadedness; rise slowly from sitting or lying down.,Avoid potassium supplements or salt substitutes containing potassium unless directed by your doctor.,Limit alcohol intake as it can increase dizziness and orthostatic hypotension.,Notify your doctor if you experience muscle cramps, weakness, irregular heartbeat, or excessive thirst.
No interactions on record
"The coadministration of Sulindac, a nonsteroidal anti-inflammatory drug (NSAID), with Chlorothiazide, a thiazide diuretic, may result in a diminished antihypertensive and diuretic effect of Chlorothiazide. Sulindac can inhibit renal prostaglandin synthesis, leading to sodium and water retention, which counteracts the natriuretic and hypotensive actions of Chlorothiazide. This interaction may result in reduced blood pressure control and potentially exacerbate edema in patients with hypertension or heart failure."
"Concomitant use of torasemide, a loop diuretic, and chlorothiazide, a thiazide diuretic, produces synergistic blockade of sodium reabsorption along the nephron, leading to profound diuresis, electrolyte disturbances, and volume depletion. This combination increases the risk of severe hypokalemia, hyponatremia, hypomagnesemia, and metabolic alkalosis, potentially precipitating cardiac arrhythmias, hypotension, or renal impairment, especially in patients with compromised renal function or those on digoxin or antiarrhythmics."
"Flurandrenolide, a topical corticosteroid, can be absorbed systemically and enhance the hypokalemic effect of chlorothiazide, a thiazide diuretic. This interaction occurs through additive potassium-wasting actions: flurandrenolide promotes renal potassium excretion via mineralocorticoid-like effects, while chlorothiazide increases distal tubular potassium loss. Clinically, this can lead to severe hypokalemia, potentially causing cardiac arrhythmias, muscle weakness, and impaired glucose tolerance."
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about ONFI vs AMILORIDE HYDROCHLORIDE AND HYDROCHLOROTHIAZIDE, 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.. AMILORIDE HYDROCHLORIDE AND HYDROCHLOROTHIAZIDE is a Thiazide Diuretic that works by Amiloride is a potassium-sparing diuretic that blocks epithelial sodium channels (ENa C) in the distal convoluted tubule and collecting duct, inhibiting sodium reabsorption and reducing potassium excretion. Hydrochlorothiazide is a thiazide diuretic that inhibits the sodium-chloride cotransporter (NCC) in the distal convoluted tubule, increasing sodium, chloride, and water excretion.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between ONFI and AMILORIDE HYDROCHLORIDE AND HYDROCHLOROTHIAZIDE 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 AMILORIDE HYDROCHLORIDE AND HYDROCHLOROTHIAZIDE is: One tablet (amiloride 5 mg/hydrochlorothiazide 50 mg) orally once daily initially, increased if needed to twice daily. Maximum dose: amiloride 10 mg/hydrochlorothiazide 100 mg daily.. 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 AMILORIDE HYDROCHLORIDE AND HYDROCHLOROTHIAZIDE 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. AMILORIDE HYDROCHLORIDE AND HYDROCHLOROTHIAZIDE is classified as Category A/B. First trimester: Limited data; thiazide use associated with possible increased risk of congenital anomalies including neural tube defects and limb reduction defects, but evidence i. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.