Carbonic Anhydrase Inhibitors

This is a very powerful diuretic class but it only works for 3 days and it’s intended for hospital use only.  They cause an increase in loss of carbonate in the urine and there’s an associated loss of sodium.

Therapeutic Uses

• Short term diuretic effect: The reason it only works for three days is because as a person losse bicarbonate, the person becomes acidic. As a person becomes metabolically acidic, the lungs kick in by breathing faster! So then you get a compensatory respiratory alkalosis.  So when that balance gets corrected, we no longer have diuresis.
• Long term glaucoma:  Another use is to lower intra-ocular pressure and this has an indefinite benefit and works for a long period of time (not limited to 3 days).

Toxicities

• Drowsiness
• Metabolic acidosis

Carbonic Anhydrase Inhibitors

These are easy to recognize because they all end in -zolamide.

Acetazolamide (Diamox) – p.o., inj.

Methazolamide (Neptazine) – p.o.

Dorzolamide (Trusopt) – ophthalmic drop. Preferred for glaucoma because it’s an eye drop and therefore has less systemic side effects.