Acetazolamide

How it works

By inhibiting carbonic anhydrase it reduces aqueous humour and cerebrospinal fluid production and promotes renal bicarbonate excretion, producing a mild diuresis and metabolic acidosis.

Prescribing in practice

• It is a sulfonamide derivative and is contraindicated in sulfonamide hypersensitivity; it can cause electrolyte disturbance, metabolic acidosis and, rarely, serious blood dyscrasias and Stevens-Johnson syndrome.
• Use with caution and dose adjustment in renal or hepatic impairment, and avoid in marked electrolyte imbalance.
• Paraesthesia of the extremities and an altered taste of carbonated drinks are common, dose-related effects.

Monitoring

Monitor electrolytes (including potassium) and consider periodic full blood count on prolonged therapy.

Counselling the patient

• Tingling of the hands and feet and a metallic taste are common and usually harmless.
• Report a sore throat, fever, rash or unusual bruising.
• Tell your prescriber if you have any allergy to sulfonamide antibiotics.

Evidence & guidelines

Acetazolamide is a recognised treatment for idiopathic intracranial hypertension and glaucoma in current prescribing references.