OCULAR TOXICITY Flashcards
Where can systemic drugs accumulate in the eye?
- melanin of the uveal tract
- cornea
- lens
Some drugs have a high affinity for…
melanin
Name an example of a drug that has a high affinity for melanin?
Chloroquine
What is problematic about chloroquine with regards to its high affinity for melanin?
It has a high affinity for melanin in the RPE, and then it is released very slowly, so it can persist for a long time
What is the adverse effect of the chloroquine-melanin complex?
renal toxicity
How do drugs bind to melanin?
-via vanderwaals forces or cation exchange
What is released when a drug-melanin complex is formed?
free radicals which cause renal toxicity
In what conditions does chloroquine cause toxicity?
- Taking the drug for more than 1 year
- Total dose greater that 100g
Define photosensitising agent?
An agent that makes another substance sensitive to light
What do photosensitising agents bind to in the cornea, lens and retina?
Macromolecules
Name some examples of photosensitising agents:
- Amiodarone
- Phenothiazines
- Psoralens
What dose of steroids correlated well with cataract formation?
Daily dose of steroids e.g. Prednisoone 15mg
What dose of steroids correlated well with cataract formation?
Daily dose of steroids e.g. Prednisoone 15mg
Which method of application of steroids causes glaucoma?
Topical
How does topical application of steroids cause glaucoma?
It decreases aqueous outflow.