Lec.12: Medical Management of Glaucoma 3 Flashcards
what happens to the osmotic gradient if drugs penetrate the eye?
decreases
when will the osmotic pressure be greater?
when there is less drug in the eye
how is mannitol distributed and what effect does it have on blood osmolality?
restricted to extracellular fluid space. this has a greater effect on blood osmolality
what is the result of increased blood osmolality?
loss of water from eye (due to hyperosmotic plasma)
what is the effect on blood osmolality if a patient ingests fluids after taking an osmotic drug.
decreases blood osmolality
which method of administration allows for more rapid and greater osmotic gradient due to bypassing the GI tract?
Intravenous
what are the indications for osmotic drugs?
short term treatment of acute and marked elevation of IOP, angle-closure glaucoma, aqueous misdirection syndrome and secondary glaucoma
what is aqueous misdirection syndrome?
aqueous humor gets pushed toward the vitreous. even if the anterior chamber appears normal the pressure will be high
in what cases are osmotic drugs contraindicated?
anuria, severe dehydration, pulmonary edema, cardiac deompensation, renal/hepatic disease and hypervolemia (excess fluid in blood)
what is the treatment regimen for isosorbide?
45% wt/vol solution, 1-2 g/kg of body weight and take 2-4 doses per day in the short term
what can happen if mannitol is stored below room temperature?
crystals can form and lead to formation of emboli
what affects does glycerol have on blood glucose?
cause rise in blood glucose levels (watch out for diabetics)
how are isosorbide and glycerol administered?
oral
what is the clinic use for osmotic drugs?
quickly lower IOP in event of angle closure glaucoma
(T/F) isosorbide may cause less nausea and vomiting than glycerol and not metoblize to glucose?
true
how many cal/g does glycerol produce?
4.34 cal/g
where is glycerol metabolized?
80% in the liver and 20% in kidney
what is the caloric load of isosorbide?
none
what is the calorie load of ethyl alcohol?
7 cal/gm
what induces hypotonic diuresis?
alcohol
what drugs are administered intravenously?
mannitol and urea
which IV drug experiences a greater rebound of IOP?
urea
how is pediatric glaucoma usually treated?
surgically
what is teratogenicity?
capability of producing fetal malformation
what is a class D drug?
clear risk
what is a class X drug?
known to cause birth defects and should never be used during pregnancy
what is a class B drug?
animal safety data but no human data to confirm
what is a class C drug?
either animal studies with adverse effects or no human or animal data
what FDA class do most glaucoma drugs fall under?
class C
what class does brimonidine belong too?
class B
lower levels of metabolic enzymes prolong half-life of medications in children by how much?
factor of 2 to 6
what concentration of timolol should be used on the young?
0.25%
what can cause growth retardation and metabolic acidosis in children?
oral CAI’s
which oral CAI is well tolerated by children in does of 5-15 mg/kg per day?
acetozolamide
