EpilepsyRx

Acetazolamide

Generic tablets / injection · Diamox (original brand)

DailyMed-verified antiseizure indications

Indication / use

Label / evidence summary
Immediate-release tablets and injection: adjunctive treatment of centrencephalic epilepsies, described in the label as petit mal and unlocalized seizures. Extended-release capsules: no U.S. antiseizure indication.
Role
Maintenance
Class
Carbonic anhydrase inhibitor

Indications checked 27 September 2026. Product, route, age, and treatment-role limits apply. A DailyMed listing alone does not establish FDA approval.

Formulations & strengths

U.S. product labels; strengths per dosage unit.

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
Immediate-release tablets / IV label: suggested total 8–30 mg/kg/day in divided doses; usual total 375–1,000 mg/day. For add-on therapy, the label suggests 250 mg once daily initially, then individualized increases. This is not an emergency rescue regimen.
Pediatric
Pediatric safety and effectiveness have not been established in these U.S. labels. Their historical weight-based epilepsy schedule must not be treated as an approved pediatric age range.
Titration / repeat dosing
Individualize gradual dose changes. Check acid–base balance, electrolytes and renal function; extended-release capsules have no seizure indication in the cited U.S. label.

Practical administration

Product instructions
Tablets are taken orally. For the cited injection, reconstitute the 500 mg vial with at least 5 mL sterile water for injection. Direct IV administration is preferred; IM administration is not recommended.

Dose adjustment & concentrations

Renal impairment
Contraindicated in marked kidney disease or dysfunction; monitor for acidosis, electrolyte abnormalities and stones.
Hepatic impairment
Contraindicated in marked liver disease or dysfunction and cirrhosis, where encephalopathy may be precipitated.
Serum reference information
No established therapeutic serum range is supplied in the cited label.

Safety

Boxed warning
No boxed warning in the cited label.
Contraindications
Low serum sodium or potassium; marked renal or hepatic dysfunction; adrenal insufficiency; hyperchloremic acidosis; hypersensitivity to acetazolamide. Cirrhosis and certain chronic angle-closure glaucoma use are also contraindicated.
Serious precautions & monitoring
Metabolic acidosis, electrolyte depletion, renal stones, severe sulfonamide reactions and blood dyscrasias. Baseline and periodic blood counts / platelets and electrolyte monitoring are advised.

Common / selected adverse effects

  • Paresthesias
  • Taste changes
  • Polyuria
  • Gastrointestinal symptoms
  • Fatigue / drowsiness

Selected label-reported effects; frequencies cannot be compared across drugs.

Drug interactions: toxicity & clinical action

Partner / combinationClinical effectClinical action
High-dose aspirinPotential severe metabolic acidosis and CNS toxicity.Avoid this combination or follow specialist review of the full label.
Other carbonic anhydrase inhibitors / sodium bicarbonateAdditive acidosis or increased stone risk.Review the combination and renal / electrolyte monitoring.
Phenytoin / primidonePhenytoin exposure may increase; primidone absorption and metabolite concentrations may fall.Review concentrations, toxicity and seizure control when adding or stopping acetazolamide.

Selected interactions; consult the full label and complete medication list.

Pregnancy & contraception

Fetal / neonatal risk
Animal studies show fetal toxicity and malformations. Adequate controlled human pregnancy studies are lacking; the label requires a benefit–risk assessment.

Clinical evidence

Research summaries describe studied populations and outcomes; they do not add indications or constitute treatment recommendations.

Product-label evidence

Trial summary

Study design / duration
No modern pivotal randomized trial is summarized in the cited label.
Primary endpoint
No quantified pivotal endpoint supplied in the cited label.

This profile uses product-label evidence; no pivotal journal publication is asserted.

Comparative evidence

Findings
No head-to-head efficacy comparison is summarized.

Mechanism of action

  • Inhibits carbonic anhydrase. Antiseizure activity has been attributed to effects within the CNS and/or the resulting acid–base changes; the label does not establish a single mechanism.

Pharmacology

Adult values unless specified. Vd/F denotes apparent oral distribution volume.

Pharmacokinetics

Bioavailability
Absolute bioavailability is not quantified in the cited product label.
Elimination half-life
Approximately 4 hours in the cited UK tablet SmPC.
Volume of distribution
Not quantified in the cited product label.
Active metabolite(s)
No active metabolite identified; urinary elimination is as unchanged drug.
Active-metabolite half-life
Not applicable: no active metabolite identified.
Protein binding
Binds to carbonic anhydrase in tissues; a plasma protein-binding percentage is not given in the cited SmPC.
Metabolism / elimination
Excreted unchanged in urine; concentrated in tissues containing carbonic anhydrase, including red cells and renal cortex.

Values reflect the cited product and study population; they are not interchangeable across formulations.

Molecular structure

Molecular structure of Acetazolamide
Principal compound; salt and product forms may differ.
NIH PubChem structure and record ↗

Product history

Initial U.S. approval
July 27, 1953 — Diamox (NDA 008943)
Market / formulation history
Original Diamox tablet products are listed as discontinued in the FDA application record; generic tablets and injection retain current DailyMed labels. A label listing does not establish stock availability.
Brands
Generic tablets / injection · Diamox (original brand)
Manufacturer / marketer
ANI (representative tablets); Hikma (representative injection); Avet (representative ER capsules)
Generic availability
Yes — representative U.S. generic labels are linked.
Related drugs
Sulthiame, topiramate and zonisamide also inhibit carbonic anhydrase, among other actions.

Sources & review status

Generic tablet, injection and extended-release labels are representative sources. The original Diamox brand insert is linked separately; formulation indications differ.

Brand reference: Diamox tablets (original brand; discontinued) ↗

Indications and DailyMed PDFs checked: 2026-09-27. Other profile sources reviewed: 2026-09-27 · label revision noted at that review: Representative tablet, injection and ER labels reviewed September 2026; Diamox FDA insert 2025.. This is a draft reference; final review is pending.

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