Eyedocs pharmacology Flashcards
What are the actions of the parasympathetic pathway? (4)
- Ciliary muscle contaction –> accomodation
- Sphincter muscle constriction –> dilation
What are the actions of the sympathetic pathway?
- Ciliary muscle relaxation
- Sphincter pupillae action –> pupil miosis
- Upper lid retraction (Dalrymple sign)
What neurotransmitter is secreted in the sympathetic pathway?
Acetylcholine
What are the mechanism of pilocarpine? (6)
sympathetic agonist - acts on muscarinic / Ach receptor
- Iris sphincter contraction - pupil miosis
- Ciliary muscle contraction - accomodative spasm (can treat accomodative esotropia by reducing drive for convergence)
- Ciliary muscle contraction –> lens thickening and move forward –> iris moving forward –> narrow anterior chamber angle –> COAG
- Ciliary muscle contraction –> increases tension on scleral spur –> opening of trabecular meshwork (conventional route) –> reduce IOP
- Ciliary muscle contraction –> myopia
6 –> increased vascular permeability (should be avoided in uveitis)
Which drugs can reverse atropine mydriasis?
Which drugs can reverse phenylephrine mydriasis?
- Pilocarpine
- Pilocarpine, thymoxamine (more effective)
Which HIV drugs are reverse transcriptase inhibitors?
Which HIV drugs are protease inhibitors?
Didanosine, Zidovudine, Zalcitabine
Ritonavir
What are the main side effects of carbonic anhydrase inhibitors (6)
- Paraesthesia
- Malaise complex (fatigue, weight loss)
- GI complex: diarrhoea, nausea, cramps
- Renal stone formation (calcium oxalate/phosphate)
- Steven-Johnson’s
- Bone marrow suppression/aplastic anaemia
- use in caution in patients with corneal endothelial dysfunction - affects endothelial pump mechanism
What type of beta blocker is betoxalol? What is its protective effect?
Cardioselective (greater effect on B1 on myocardium vbs B2 on respiratory/ocular system)
Protective effect on VF preservation due to effects on microperfusion of optic disc
What are the effects of betoxalol? (2)
- Less oculohypotensive effect than timolol
- Greater effect on visual field preservation due to effects on microperfusion of optic disc
Which immunosuppressant has an enhanced effect with allopurinol?
azathioprine –> patients need reduced dose on this
What is the mechanism of action of botox?
inhibition of release of ACh from presynaptic nerve terminals
What is the mechanism of action of apraclonidine?
alpha-2-adrenergic agonist (partial) –> potent systemic anti-hypertensive –> causes mydriasis
Acts on the presynaptic nerve endings and are inhibitory –> prevent further release of neurotransmitter
Has very little alpha-1 activity
What are the effects of apraclonidine? (3)
- Mydriasis
- Eyelid retraction
- Conjunctival blanching
What are the optic side effects of vigabatrin? (3)
- Optic Nerve Pallor
- RNFL atrophy
- Concentric peripheral field loss (binasal field defect with macula sparing)
What is the mechanism of action of dorzolamide or brinzolamide?
- Transient bitter taste
What compounds are most likely to penetrate the cornea to reach the anterior chamber (ie biphasic - both hydrophilic and hydrophobic) (3)
- Acetate (most)
- Alcohol
- Phosphate (least)
Which class of IOP lowering agents is most chemically similar to sulphonamides?
Carbonic anhydrase inhibitors
What drugs can cause corneal verticillata / vortex keratopathy? (5 + 1)
- Chloroquine
- Hydroxychloroquine
- Amiodarone
- Indomethacin
- Phenothiazines
- Fabry’s disease
What is the mechanism of action of prostaglandins?
Increase uveoscleral outflow –> increased aqueous outflow.
Which beta blocker will induce less bradycardia and postural hypotension than the others?
Carteolol - has intrinsic sympathetic activity.
What are the main complications of overtreatment with topical antivirals for HSK? (3)
- Follicular conjunctivitis
- Punctate keratitis with photophobia
- Sterile corneal ulceration
What is the main ocular side effects of brimonidine / apraclonidine?
After 1 year - allergic conjunctivitis, follicular conjunctivitis
What are the main side effects of topical prostaglandin analogues? (7)
- Increased iris pigmentation
- Iris cyst formation
- Increased peri-ocular skin pigmentation
- Peri-orbital fat atrophy
- Eyelash hypertrichosis
- Iritis
- CMO
What is the mechanism of action of quinolones?
ciprofloxacin
Blocks DNA synthesis by inhibiting DNA gyrase
Which antibiotics inhibit bacterial cell wall synthesis? (3)
Penicillins, cephalosporins (ceftriaxone), vancomycin
Where are Beta-2 receptors found? (3)
Lungs, GI tract, vascular smooth muscle
What is the systemic effect of leukotrienes? (3)
- Bronchoconstriction
- Vasoconstriction
- Increase vascular permeability
–> involved in allergic reactions and inflammation
What drugs can induce optic neuropathy? (14)
Anti-Tb: Isoniazid, Ethambutol
Antibiotic: erythromycin, streptomycin, quinine, linezolid, dapsone (sulphonamide), chloramphenicol
Anti-retrovirals
Others: Amiodarine, Clioquinol, Infliximab, Pheniprazine, Suramin
Systemically, what can chloramphenicol cause?
aplastic anaemia
What are the ocular side effects of pilocarpine? (7)
- Miosis
- Induced myopia (myopic shift)
- Conjunctival vascular congstion
- Punctal stenosis
- Cataract formation
- Retinal detachment
- Headaches/brow ache
Which drugs should be avoided in myaesthenia gravis? (9)
- Aminoglycosides (gentamicin)
- Fluoroquinolones (ciprofloxacin, levofloxacin)
- Macrolides (erythromycin, azithromycin)
- Beta blockers
- Chlorpromazine
- Procainamide
- Penicillamine
- Respiratory supplements
Which topical steroid is least likely to induce intraocular pressure elevation?
Loteprednol etabonate
Which antibiotics inhibit protein synthesis? (5)
Which antibiotics inhibit 30S subunit
Which antibiotics inhibit 50S subunit
30S: tetracycline, aminoglycosides (messenger RNA)
50S: Macrolides, Lincosamides, Chloramphenicol
What antibiotics inhibit cell wall synthesis?
Beta lactam antibiotics - penicillin, cephalosporins
What antibiotics inhibit folic acid synthesis?
Sulphonamides
Trimethoprim
What antibiotics inhibit DNA gyrase and transcription?
Fluoroquinolones