Ocular Pharm Flashcards
how to calculate eye drop measurements
- expressed as a % solution = parts per 100 i.e. 1% = 1g per 100cc
example problem: how many mg of atropine in 5cc of 1% solution?
(1g/100cc) x 5cc = 0.05g = 50mg
path of eye drops through the eye
nasolacrimal duct –> mucosa
- no first pass effect through GI or liver
when do you use anesthetic eye drops? examples of anesthetic drops?
- ONLY for diagnostic purposes – NEVER give to pts or allow access to pts
- w/ excessive use the eye will literally melt
- tetracaine and proparacaine (better tolerated)
epinephrine: uses, effects
- increases trabecular outflow w/ small increase in aqueous production
- causes vasoconstriction, mydriasis
- mostly alpha effects w/ slight beta
- has been used to tx glaucoma but not much anymore
phenylephrine
- dilates the eye but doesn’t change your vision much = not much blurring
- direct acting alpha agonist
- alpha-1 selective, little effect on beta
- no effect on ciliary muscle
apraclonidine
- alpha agonist (mostly alpha 2)
- lowers IOP by decreasing aqueous production
- does not cross BBB in adults; no effect on BP; almost no cardiac effect
- CAUSES SOMNOLENCE IN KIDS = don’t use for kids
what drugs do NOT decrease aqueous production?
prostaglandin analogs
brimonidine
- *can cause sedation by stimulating central alpha-2 receptors
- *can’t use in kids b/c of CNS suppression
- decreased aqueous production; increases uveoscleral outflow
- less allergy than apraclonidine
- no effect on heart rate or BP
timolol
- nonspecific beta blocker
- decreases aqueous production
- no change in vision, pupil or accommodation
- IOP decrease seen in 30-60 minutes
- less effect at night; taken BID
- s/e: masks hypoglycemic episodes
betaxolol
- BETA-1 SELECTIVE beta blocker
- decreases aqueous production by 32-47%
- no effect on outflow or pupil
- less potent than timolol but safer to use in lung disease
cholinergic meds
- direct acting = ACh, carbachol, pilocarpine
- indirect = physostigmine, echothiophate
- ACh & carbachol used in cataract surgery
- pilocarpine = increased chance of retinal detachment in contact wearers
methacholine
- 2.5% solution used to dx Adie’s tonic pupil
- more resistant to cholinesterase
- can be administered topically
pilocarpine
- can cause pupillary block in high concentrations = mechanism for acute angle glaucoma
- induces myopia, increases trabecular outflow and decreases uveoscleral outflow
- would not give if IOP is 40+ b/c of ciliary shutdown; you will make things worse
what kind of meds should you not use for sickle cell pts?
- carbonic anhydrase inhibitors (CAIs)
- they will increase the sickling of RBCs
1st line drugs for glaucoma? examples
- prostaglandin analogs
- increases uveoscleral outflow but not production
- lowers IOP by 33%
- latanoprost (xalatan), travoprost (travatan), bimotoprost (latisse); all similar efficacies
- latisse also causes increased eyelash growth; can get darkening around eyes/iris
s/e of prostaglandin analogs
- hyperemia
- darkening of irides and periorbital skin
- hypertrichosis/eyelash growth (only w/ bimatoprost [latisse])
- reversible CME (cystoid macular edema) = edema in the macula
what conditions would you tx w/ corticosteroids?
- uveitis
- corneal edema
- hyperemia
- conjunctivitis
- macular edema
contraindications for corticosteroids?
- acute epithelial HSV, fungal eye disease
- after removal of superficial corneal foreign body (prevents healing)
- acute, untreated eye infections = would need antibiotics before every using a steroid
example of med NOT to use for contact lens wearers?
- levocabastine
- blocks H1 receptor sites; works in minutes
fluoroquinolones
- increases pseudomonas coverage = use for contact lens wearers
macrolides
- erythromycin = most commonly used
- azithromycin and clarithromycin also could be used
- not effective v. pseudomonas = NOT for contact lens wearers
- good for tx of blepharitis and bacterial conjunctivitis
what would you use to treat endophthalmitis?
- INTRAVITREAL antibiotics
what would you see on the cornea to suggest an HSV infection
- dendritic lesion
- would tx w/ trifluridine
ocular s/e of systemic meds
- digitalis causes changes in visual perception
- amiodarone = accumulates in cornea; doesn’t affect vision; can cause optic neuropathy
- hydroxychloroquine = bulls eye maculopathy
s/e of topamax
- acute myopia
- b/l acute angle closure
- ciliary body swelling and choroidal effusions
s/e of sildenafil
- blue haze in vision
- light sensitivity
- pupil sparing CNIII palsy
