Pharmacology of Carbonic Anhydrase Inhibitors

Mechanism of Action:

Carbonic Anhydrase Inhibitors (CAIs) act primarily on the proximal convoluted tubule in the kidneys. They inhibit the enzyme carbonic anhydrase, which is essential for the reabsorption of bicarbonate ions. This leads to increased excretion of bicarbonate, sodium, and water, resulting in mild diuresis and acidification of the urine.

Pharmacokinetics:

• Absorption: Generally well-absorbed orally.
• Distribution: Widely distributed in the body.
• Metabolism: Minimal metabolism.
• Excretion: Primarily renal excretion.

Drug Examples:

• Acetazolamide (Diamox): Most commonly used; also used for glaucoma and altitude sickness.
• Methazolamide: Less commonly used; mainly for glaucoma.

Clinical Use:

1. Glaucoma: To reduce intraocular pressure.
2. Metabolic Alkalosis: To correct alkalosis conditions.
3. Altitude Sickness: To mitigate symptoms.
4. Epilepsy: As an adjunctive treatment.

Side Effects:

• Metabolic Acidosis: Due to bicarbonate loss.
• Hypokalemia: Low potassium levels.
• Renal Stones: Risk of calcium phosphate stones.
• Paresthesia: Tingling sensation in extremities.

Drug Interactions:

• Salicylates: Increased risk of toxicity.
• Other Diuretics: Increased risk of electrolyte imbalance.

Contraindications:

• Severe renal or hepatic impairment.
• Hyperchloremic acidosis.
• Hypokalemia.

Understanding the pharmacology of Carbonic Anhydrase Inhibitors is essential for healthcare providers to effectively treat conditions like glaucoma and metabolic alkalosis while minimizing side effects.

Disclaimer: This article is for informational purposes only and should not be taken as medical advice. Always consult with a healthcare professional before making any decisions related to medication or treatment.