Glaucoma D

Question 1

Hyperosmotic Agents: Clinical uses & mechanism of action

Answer 1

Uses
* acute angle closure glaucoma (AACG)
* pre-surgery to decrease IOP
Mechanisms of action
* decrease inflow (by osmosis)
* increase outflow (by osmosis)
* requires maintained osmotic gradient
* onset time of 15 - 60 min; duration 4 - 6 h

Question 2

Hyperosmotic agents

Answer 2

glycerol - oral - metabolized to glucose; rel weak penetration
isosorbide - oral - not metabolized; penetrates cells
mannitol - IV - not metabolized; weak penetration ( even in inflamed eyes)

Question 3

Hyperosmotic agents: Contra-indications

Answer 3

• diabetes (glycerol)
• cardiovascular disease
• kidney disease
• pulmonary disease
• dehydration
• hypersensitivity (isosorbide)

Question 4

Hyperosmotic agents: Systemic side-effects

Answer 4

All Drugs
* nausea &/or vomiting
* dehydration
* headache
* confusion/disorientation
* lethargy
IV Drugs (mannitol)
* arm/chest pain
* chills
* rapid diuresis (urea)
* raised BP?

Question 5

Neovascular glaucoma & off-label Avastin (bevacizumab)

Answer 5

Treatment protocol: intracameral & intravitreal injections of avastin (125 mg in 0.05ml)

Question 6

The future of medical therapy for glaucoma

Answer 6

• Pharmacogenomics
• Neuroprotection
• Improved formulations
• Application gene therapy technology
• New drug applications
• New drug developments
• New anterior segment surgeries (e.g., stent)