Ocular Pharm Flashcards
Cholinergic Receptors in the eye
Iris sphincter- M3
Lacrimal gland- M2 and M3
Ciliary muscle- M2 and M3
Adrenergic receptors in the eye
A1- Dilator muscle
A2- Ciliary body vasculature to reduce aqueous formation
B1 and B2- Non pigmented ciliary epithelium to increase aqueous formation.
B2- TM to increase outflow, ciliary muscle to oppose accommodation, NPCE to increase aqueous formation.
Pilocarpine
- What class
- How many drops per day
- MOA
- When to use
- Side effects
- Cholinergic agnost
- QID
- Stimulates longitudinal muscle of the ciliary body, which pulls on the scleral spur and opens up the TM
- After angle closure attack, before PI. To differentiate Aide’s or 3rd nerve palsy vs sphincter tear.
- Browaches, HA, myopia, RD
Indirect cholinergic agonists (anticholinesterase agents)
4
Endrophonium- dx MG (tensilon test)
Neostigmine- Tx MG
Pyridostigmine- Tx MG
Echothiophate- longest lasting, IRRIVERSIBLE. Dx and Tx of accommodative ET
What class of drugs can be used to tx accommodative ET?
Cholinergic agonists because they increase ACH at the receptor. The brain now sends less signals to converge.
Irreversible anti cholinesterase agents
Echothiophate and isofluorophate
-Many side effects
Pralidoxime MOA
Administered by IV. Reverse the effects of irreversible acetylcholinesterase inhibitors such as echothiophate and isofluorophate.
It binds to these drugs and releases the acetylcholinesterase, which can now break down Ach.
Can reverse systemic side effects of organophosphate poisoning.
Not effective against reversible acetylcholinesterase inhibitors like neostigmine.
Cholinergic antagonists (5)
Atropine Homatropine Scopolamine - penetrates BBB best and may cause hallucinations, confusion, restlessness. Tropicamide Cyclopentolate
Drug with the fastest onset and shortest duration of MYDRIATIC effects
Tropicamide
Max mydriatic effect of tropicamide is in __ minutes
25
Atropine onset and duration
- When to use
- Avoid in
60-180 minutes
7-12 days
-Amblyopia Tx (drop the good eye, penalization)
-Downsyndrome, under 3, elderly
Special caution when using atropine in what demographics
**Down syndrome
Under 3 years old
Elderly
Atropine toxicity
Dry mouth, dry flushed skin, rapid pulse, disorientation, fever. Due to CNS effects
Fastest onset and shortest duration of CYCLOPLEGIC effects
Cyclopentolate.
Wait 45 minutes
Standard for treating anterior uveitis
Homatropine because it dilates the pupil, but keeps it mobile so the iris cannot become syneched in miotic or dilated stages.
BID!
- Keeps iris mobile
- Reduces pain by paralyzing ciliary muscles and sphincter muscles.
- Causes vasoconstriction –> stabilizing blood aqueous barrier.
MOA of botox
Somatic drug that blocks the release of Ach at the NMJ, inhibiting muscle contraction. Can be used for blepharospasm, strab, and wrinkles.
What receptors do NE and Epi act on
Epi- Alpha 1, alpha 2, beta 1, beta 2
NE- Alpha 1, alpha 2, beta 1
Alpha 1 agonist
Phenylephrine
Clinical uses of 2.5% phenylephrine
Dilation without cyclo- only acts to increase action of dilator muscle, does not prevent sphincter muscle.
Palpebral widening- acts on mullers (sympathetic)
Differentiates scleritis from episclertisi due to blanching. (sympathetic drugs cause peripheral vasoconstriction)
10% breaks PS, but contraindicated in patients with Graves, taking MAOIs, tricyclic antidepressants, and atropine.
Horners Dx
Contraindications for phenyl 10%
Taking MAOIs, tricyclic antidepressants, atropine
Or patients with Graves disease.
May result in adverse cardiovascular effects such as HTN crisis and cardiac arrhythmias.
Topical ocular decongestants
Naphazoline and Tetrahydrozoline (Visine)
Considered an adrenergic alpha agonist, but also has some beta effects.
Naphcon is a combo of which 2 drugs
Naphazoline (adrenergic agonist, alpha > beta = vasoconstriction) and antihistamine
Adrenergic alpha2 agonists used for glaucoma therapy
Brimonidine (alphagan 0.20%–> Alphagan P 0.1% )
Apraclonidine (Iopidine)
-Both can cause dry mouth
Brimonidine
Alphagan 0.2% –> Alphagan P 0.1%
- Highly selective alpha 2 agonist
- Neuroprotective properties
- Alphagan 0.2% may cause follicular conjunctivitis, which is why they switched to Alphagan P 0.1%
- Causes miosis
- Contra in pt’s taking MAOIs.
Why does brimonidine (alphagan P 0.1%) cause miosis and apraclonidine (iopidine) cause mydriasis?
Both act on the alpha adrenergic receptors.
Brimonidine has 30x more effect on Alpha 2 than apraclonidine.
Alpha 2 decreases sympathetic activity
AKA brimonidine decreases sympathetic activity more –> constricted pupil.
When to use apraclonidine (iopidine)
Acute angle closure because fast acting (within 1 hour) and decreases IOP by 30-40%
NOT effective in chronic therapy because tachyphylaxis and at risk of allergic response.
Can be used for dx of Horner’s Syndrome
What 2 signs need to be present for you to dx Horner’s without pharm testing
- Dilation lag of affected pupil in darkness. When you turn light off, abnormal pupil will not dilate because there is a sympathetic problem. Aniso will be greater in darkness.
- Ptosis
Horner’s Dx with pharm
Apraclonidine- Horner’s pupil will dilate.
Cocaine- Horner’s pupil will stay the same.
Horner’s syndrome Dx location of lesion
Hydroxyamphetamine
Phenylephrine- Will dilate if lesion is pre ganglionic,
How much does Timolol reduce IOP
25%
Which class of drugs has a crossover effect (can drop OD, get effects OS)
BB
Cosopt
Timolol 0.5% and Trusopt (Dorzolamide) 2%
Combigan
Timolol 0.5% and alphagan (brimonidine) 0.2%