Wk 15 - CAIs Flashcards
Topical CAI Indications
1) Primary open angle glaucoma
2) Ocular hypertension
CAI MOA
These drugs inhibit the enzyme carbonic anhydrase, which is responsible for the formation of bicarbonate in the ciliary epithelium
• Bicarbonate is an essential component of the aqueous, so aqueous production is decreased
• Decreased aqueous production decreases IOP
Topical CAI Formulations
Trusopt = Dorzolamide 2% solution - Merck
Asopt = Brinzolamide 1% susp - Alcon
Cosopt = Dorz 2% / Timolol 0.5% - Akorn
*Cosopt PF = same as above
*Simbrinza = Brinz 1% / Brimonidine 0.2% - Alcon
last two have no generic available
Dorzolamide more effective than Brinz,
But Briz has fewer side effects
Dorzolamide 2% sol (Trusopt)
Decreases IOP 20-25%
Dosing
• Monotherapy - TID
• In combination – BID
Cosopt
Dorzolamide 2% / Timolol 0.5% solution
• 27% decrease in IOP
Dosing: BID
Not more effective than using dorzolamide and timolol separately
However, compliance is better
Available in preservative free, unit dose
• Cosopt PF
Brinzolamide 1% susp (Azopt)
Decreases IOP 15-20%
Dosing
• Monotherapy – TID
• In combination – BID
Suspension is more comfortable, but must be shaken
High affinity for carbonic anhydrase II
• Lower concentration needed
• Fewer side effects
• Still not as effective as dorzolamide
Simbrinza
Brinzolamide 1% / Brimonidine 0.2%
• Decreases IOP 21-35%
Dosing: TID
First combo drug that doesn’t contain timolol
• New option for patients with timolol contraindications
Topical CAI as Additive Treatment
CAIs are a great addition to PGA therapy
o Not often used alone
o Ex. Brinzolamide is more effective than brimonidine when added to travoprost
Reduce nocturnal IOP
o Beta-blockers do not
Start with qday beta-blocker or PGA
o Can add a CAI AM/PM to PM PGA for BID therapy
Topical CAI Side Effects
Ocular 1) Burning and stinging • Dorzolamide>brinzolamide 2) Blur • Brinzolamide>dorzolamide 3) SPK, tearing, dryness, photophobia • Especially in patients with DES 4) Allergic reaction in ~4% of patients • All CAIs are sulfa drugs • Do not give to a patient with a sulfa allergy 5) Rare irreversible corneal edema • In corneas already compromised by something like Fuch’s • Recorded with dorzolamide
Systemic
o Metallic taste in 25% of patients
Contraindications • Renal failure • Hepatic failure • Sulfa allergy • Concurrent use with systemic CAIs
Systemic CAI Indications
Short-term control of IOP
1) Acute angle-closure glaucoma (ACG)
2) Secondary glaucoma
Rarely used for POAG
o Side effects
Acetazolamide (Diamox, Diamox Sequels ER)
IOP decreased 40-50%
Dosing
1) Two 250 mg tabs q6h
-Onset in 0.5-1 hour with max effect 2-4 hours
• 6 hour duration
2) One 500 mg extended release cap BID
• Onset 1-2 hours with max effect 8-12 hours
• NOT used for ACG / Best for CME or macular edema (Diamox ER BID for 2 wk)
Clinical uses • ACG or neovascular crisis • Pre-operative to prevent IOP spikes • Pseudotumor cerebri • CME or macular edema
Potent diuretic
• Limited use due to side effects
Methazolamide (Neptazene, GlaucTabs)
IOP decreased 3-6 mmHg
• Less effective than acetazolamide
Dosing: 25-100 mg q8h
Side effects less severe than acetazolamide
- Mainly metabolized in liver ; minimal risk of kidney stones
Oral CAI Side Effects
Ocular
o Sulfa allergies
o Transient myopia
Systemic
1) Metabolic acidosis
2) Calcium deposits in urinary tract
3) Numbness/tingling of perioral and periocular areas and extremities
4) Malaise, fatigue, weight loss, depression, decreased libido
5) Blood dyscrasias
• pathologic condition in which any of the constituents of the blood are abnormal in structure, function, or quality, as in leukemia or hemophilia.
6) Metallic taste
Oral CAI Contraindicatoins
• Sulfonamide allergy • Sickle cell anemia • Renal disease including kidney stones • Liver disease • Pregnant/nursing mothers • Concurrent use of K+ depleting drugs (Diuretics, digitalis, steroids) - May make K+ levels too low
