Tablet
- Strengths
- 0.5, 1, 2 mg
- Product note
- Oral maintenance product.
Clonazepam
Klonopin
DailyMed-verified antiseizure indications
Indication / use
- Label / evidence summary
- Klonopin: alone or as adjunctive therapy for Lennox-Gastaut syndrome, akinetic seizures, and myoclonic seizures; it may help absence seizures after succinimides have failed.
- Role
- Maintenance
- Class
- 1,4-benzodiazepine
Indications checked 26 September 2026. Product, route, age, and treatment-role limits apply. A DailyMed listing alone does not establish FDA approval.
- Klonopin tablet U.S. label
Lennox-Gastaut syndrome, Myoclonic seizures, Absence, Akinetic seizures · Exact minimum age not mapped · MaintenanceAbsence only after succinimide failure; label does not state a single minimum age.
Formulations & strengths
U.S. products unless another country is named. Strengths are per unit or stated volume.
Orally disintegrating tablet
- Strengths
- 0.125, 0.25, 0.5, 1, 2 mg
- Product note
- Dissolves in the mouth; not an FDA-labeled seizure-cluster rescue product.
Brand & formulation labels
Each link names the product and formulation it covers. Archived labels do not establish current availability.
Dosing & administration
- Adult / product-specific schedule
- Start ≤1.5 mg/day in 3 doses; individualized maintenance, maximum 20 mg/day.
- Pediatric
- ≤10 years or ≤30 kg: start 0.01–0.03 mg/kg/day in 2–3 doses (initial ceiling 0.05 mg/kg/day); maintenance 0.1–0.2 mg/kg/day.
- Titration / repeat dosing
- Adults: add 0.5–1 mg/day every 3 days. Children: add ≤0.25–0.5 mg/day every 3 days; stop escalation for control or toxicity. Gradual individualized taper.
Dose adjustment & concentrations
- Renal impairment
- Caution: metabolites undergo renal elimination.
- Hepatic impairment
- Contraindicated in significant liver disease.
- Serum reference information
- Clinical response guides dosing; no routine target here.
Safety
- Boxed warning
- Boxed: opioid-associated respiratory depression, abuse/misuse/addiction, and dependence/withdrawal. No reliable single incidence estimate; risk depends on exposure and co-sedatives. Avoid abrupt withdrawal after repeated use.
- Contraindications
- Benzodiazepine hypersensitivity; significant liver disease; acute narrow-angle glaucoma.
- Serious precautions & monitoring
- Tolerance can reduce benefit. Avoid significant liver disease; monitor sedation and behavior.
Common / selected adverse effects
- Seizure-treatment experience: drowsiness; ataxia; behavioral problems
Drug interactions: toxicity & clinical action
| Partner / combination | Clinical effect | Clinical action |
|---|---|---|
| Opioids / alcohol / other sedatives | Additive respiratory depression and profound sedation. | Avoid unnecessary combinations; monitor closely. |
| CYP3A inhibitors / enzyme-inducing ASMs | Inhibitors may increase exposure; inducers reduce it. | Monitor sedation or breakthrough seizures when the partner is added/removed. |
| Valproate | Absence status has been reported with the combination. | Investigate prolonged staring/confusion or seizure worsening; do not assume sedation alone. |
Pregnancy & contraception
- Fetal / neonatal risk
- Clonazepam exposure late in pregnancy can cause neonatal respiratory depression, hypotonia or withdrawal. Published benzodiazepine observational data do not show a clear association with major birth defects, but do not establish absence of risk.
- Pregnancy / postpartum monitoring
- Monitor exposed newborns for sedation, feeding difficulty and withdrawal.
Clinical evidence
Research summaries describe studied populations and outcomes; they do not add indications or constitute treatment recommendations.
Extrapolation
Trial summary
- Study design / duration
- Legacy seizure indication; no contemporary pivotal seizure trial summarized in the current label.
- Primary endpoint
- No single pivotal endpoint is identified in the cited source.
- Results
- The current label does not provide a modern placebo-controlled Phase 3 seizure-efficacy estimate. Its quantified placebo-controlled trials concern panic disorder and should not be presented as antiseizure efficacy.
Mechanism of action
- A 1,4-benzodiazepine that enhances GABA-dependent gating of benzodiazepine-sensitive GABA-A chloride channels at the classical α/γ subunit-interface site. This is distinct from the GABA-binding site and from GABA-B receptors.
- The classical teaching is increased opening/burst frequency for benzodiazepines versus longer openings for barbiturates. Single-channel behavior depends on preparation and conditions, so this is a useful distinction rather than an absolute kinetic rule.
- Route, onset, duration, active metabolites and clearance distinguish these drugs clinically, but those pharmacokinetic differences are not separate receptor mechanisms.
Pharmacology
Adult values unless specified. Vd/F denotes apparent oral distribution volume.
Pharmacokinetics
- Bioavailability
- Approximately 90% absolute oral bioavailability.
- Elimination half-life
- Typically 30–40 hours (U.S. label); the UK SmPC reports a broader 20–60-hour range.
- Volume of distribution
- Approximately 3 L/kg (UK SmPC).
- Active metabolite(s)
- No major clinically established active metabolite. Amino metabolites are inactive; the UK SmPC describes trace hydroxylated nitro derivatives with pharmacologic activity, without an established clinical contribution.
- Active-metabolite half-life
- Not reported for the trace potentially active derivatives in the cited labeling.
- Protein binding
- ~85%
- Metabolism / elimination
- Hepatic; CYP3A involvement
Do not interpret “no major active metabolite” as proof that every metabolite is pharmacologically inert.
Molecular structure
NIH PubChem structure and record ↗
Product history
- Initial U.S. approval
- 1975
- Brands
- Klonopin
- Manufacturer / marketer
- H2-Pharma (distributor); licensed by CHEPLAPHARM
- Generic availability
- Yes: tablets and ODT.
- Related drugs
- 1,4-benzodiazepine; clobazam differs structurally (1,5).
Sources & review status
Representative sources are selected product labels, not an exhaustive list of generic manufacturers. Consult the exact product and formulation prescribed. Brand-name package inserts are linked separately.
Brand reference: Klonopin tablets ↗
Indications and DailyMed PDFs checked: 2026-09-26. Other profile sources reviewed: 2026-09-15 · label revision noted at that review: 1/2023. This is a draft reference; final review is pending.