Pharmacological therapy: Carbonic Anhydrase inhibitors

Question 1

How does CAI work?

Answer 1

• decrease aq humour production

- inhibit carbonic anhydase isoenzyme II located in ciliary body

Question 2

What does CA catalyze in the eye?

Answer 2

Conversion H2O + CO2 –> HCO3 + H

significant step in aq humour production

Question 3

TOPICAL CAI

Answer 3

• Dorzolamide

- Brinzolamide

Question 4

How are dorzolamide + brinzolamide administered?

Answer 4

• q8hrs
• nasolacrimal occulusion may allow q12hr dosing
• lower peak + trough

Question 5

Use of dorzolamide + brinzolamide?

Answer 5

• adjunctive therpay/ monotherpay

= who cant tolerate 1st line therapies

Question 6

Local side effects

Answer 6

1. burning
2. stinging
3. itching
4. forgein body sensation
5. dry eyes
6. conjunctivities
   Brinzolamide fewer s/e = neural pH soln
7. taste abnormalities reported in both drugd
8. sulphonamides - sulfa allergy - hypersentivity

Question 7

Systemic CAI

Answer 7

Acetazolamide only one registered in SA

reserved 3rd/4th line agent

Question 8

use of acetazolamide

Answer 8

• bridge therpay from maximal medical therpay to laser/surgical intervention/ control IOP in postoperative period
• lower IOP PACG

Question 9

Adverse effects of Acetazolamide

Answer 9

1. paresthesias of hands + feet
2. N + V
3. weight loss

Question 10

systemic s/e acetazolamide

Answer 10

1. systemic acidosis
2. hypokalemia
3. nephroliathiasis - due to inhibition renal carbonic anhydrase

Question 11

C/I systemic CAI

Answer 11

1. sulphonamide allergy
2. renal failure
3. hepatic insufficiency
4. COPD
5. decreased serum K + Na levels

Question 12

Have blood dyscrasias from BM suppression reported?

Answer 12

• agranulocytosis
• aplastic anemia
• neutropenia
• thrombocytopenia