Carbonic Anhydrase Inhibitors

Carbonic Anhydrase Inhibitors

  1. Acetazolamide
  2. Dorzolamide
  3. Dichlorphenamide
  4. Methazolamide

Mechanism Of Action :

Inhibition of carbonic anhydrase enzyme

Inhibition of bicarbonate ion formation in aqueous

Reduced Na2+ in ciliary body

Reduced H2O absorption

Reduced aqueous formation

Decreased IOP

Duration of Action : 6-8 hours

Frequency : QID


  1. Short term : all types of acute & chronic glaucoma
  2. Long term : reserved for patients at high risk of visual loss, where all other treatment fails.
  3. Prophylaxis : intra ocular surgery


  1. Paresthesia of fingers, toes, hands, feet & around the mouth – hence it is ALWAYS PRESCRIBED with electrolyte rich items:
    • BANANA – contra indicated in diabetics
    • SYRUP POT CHLOR (Potassium Chloride ) : if above two are not available.
  2. Urinary frequency due to diuretic effect
  3. Serum electrolyte imbalance :
    • Bicarbonate depletion : malaise, fatigue, loss of libido, anorexia & weight loss
    • K+ depletion : especially in those taking steroids too.
  4. G.I.T. : abdominal discomfort, gastric irritation, nausea, metallic taste & diarrhea
  5. Sulfonamide related side effects : S-J syndrome, renal calculi, blood dyscrasias, transient myopia, HT nephropathy, teratogenic.