ASK DIS: Acetazolamide for Idiopathic intracranial hypertension

Available product:

Acetomid/Acetazolamide 250mg Tab (short acting)

Mechanism of Action

Carbonic anhydrase inhibitors are believed to reduce the rate of cerebrospinal fluid production.

Indication

usual first line treatment for IIH (appears to be the most effective agent for lowering ICP)
Most patients experience adequate relief of symptoms (typically, headache)
However, evidence supporting its efficacy is mostly observational

Dosing

Adults

500 mg twice per day and advance the dose as required and tolerated by the patient.
Although doses of up to 2 to 4 g per day can be administered, many patients develop dose limiting side effects at higher levels
sustained release formulation (Diamox sequels) may be better tolerated

Children

25mg/kg per day with a maximum dose of 100 mg/kg or 2 g per day
25-50mg/kg TDS-QID with Frusemide 0.25mg/kg QID (Frank Shann recommendation for TB Hydroencephalus)

Interaction

Although a sulfa allergy is reported to be a relative contraindication to acetazolamide use, there is little clinical or pharmacologic basis for this recommendatio
cross-reaction between sulfonamide antimicrobials and the sulfa moiety in acetazolamide and furosemide is unlikely
For patients who have had major adverse reactions (eg, Stevens-Johnson syndrome, anaphylaxis), we usually consider that the risk precludes the use of acetazolamide. Allergy consultation or other desensitization protocols may be considered in these patients.
However, if the previous sulfa-related reaction was minor, we usually proceed with acetazolamide treatment

Side Effects and Monitoring

usually dose-related.
Monitoring of electrolytes is suggested during acetazolamide treatment.
digital and oral paresthesias, anorexia, malaise, metallic taste, fatigue, nausea, vomiting, electrolyte changes, mild metabolic acidosis, and kidney stones

References:

ASK DIS