Sulaimani Polytechnique University

College of Health and Medical Technology

Nursing Department
Clinical Pharmacology
2024-2025

Ocular Pharmacology

Practice- 9
22-4-2025
 pharmacodynamic
Biological and therapeutic effect of the drug: Mechanism of action
❑ Most drugs act by binding to regulatory macromolecules,
usually neurotransmitters or hormone receptors or enzymes
❑ If the drug is working at the receptor level, it can be agonist
or antagonist
❑ If the drug is working at the enzyme level, it can be activator
or inhibitor.
 Pharmacokinetic
➢ Absorption, distribution, metabolism, and excretion of the drug
➢ A drug can be delivered to ocular tissue as:

❑ Locally:
▪ Eye drop
▪ Ointment
▪ Periocular injection
▪ Intraocular injection
❑ Systemically:
▪ Orally
▪ IV
 Ocular Pharmaco-therapeutics
Cholinergic agonists
❑ Directly acting agonists:
▪ E.g. pilocarpine, acetylcholine (miochol), carbachol (miostat)
▪ Uses: miosis, glaucoma
❑ Mechanisms:
▪ Miosis by contraction of the iris sphincter muscle
▪ increases aqueous outflow through the trabecular meshwork by longitudinal
ciliary muscle contraction
▪ Accommodation by circular ciliary muscle contraction
❑ Side effects:
▪ Local: diminished vision (myopia), headache, cataract, miotic cysts, and
rarely retinal detachment
▪ systemic side effects: lacrimation, salivation, perspiration, bronchial spasm,
urinary urgency, nausea, vomiting, and diarrhea
Cholinergic agonists
❑ Indirectly acting (anti-cholinesterases) :
▪ More potent with longer duration of action
▪ Reversible inhibitors
▪ e.g. physostigmine
❑ used in glaucoma and lice infestation of
lashes
❑ can cause CNS side effects
 Cholinergic agonists

▪ Indirectly acting (anticholinesterases):

▪ Irreversible:
▪ e.g. phospholine iodide Esotropia
▪ Uses: in accommodative esotropia

▪ side effects: iris cyst and anterior subcapsular

cataract Cataract
▪ C/I in angle closure glaucoma, asthma,
Parkinsonism

▪ causes apnea if used with succinylcholine or procaine

Cholinergic antagonists
▪ E.g. tropicamide, cyclopentolate, homatropine, scopolamine,
atropine
▪ Cause mydriasis(by paralyzing the sphincter muscle) with
cycloplegia
(by paralyzing the ciliary muscle)
▪ Uses: fundoscopy, cycloplegic refraction, anterior uveitis
▪ Side effects:
▪ local: allergic reaction, blurred vision
▪ Systemic: nausea, vomiting, pallor, vasomotor collapse,
constipation, urinary
retention, and confusion
▪ specially in children they might cause flushing, fever, tachycardia, or
delerium
▪ Treatment by DC or physostigmine
Adrenergic Agonists
❑Alpha-1 agonists
▪ E.g. phenylepherine
❑Uses: mydriasis (without cycloplegia), decongestant
❑Adverse effect:
▪ Can cause significant increase in blood pressure specially in infant
and susceptible adults
▪ Rebound congestion
▪ precipitation of acute angle-closure glaucoma in patients with
narrow angles(glaucoma and IOP )
Adrenergic agonists
❑ Alpha-2 agonists
▪ E.g. brimonidine, apraclonidine
❑ Uses: glaucoma treatment, prophylaxis against IOP spiking after
glaucoma laser procedures
▪ Mechanism: decrease aqueous production, and increase uveoscleral
outflow
❑ Side effects:
▪ local: allergic reaction, mydriasis, lid retraction, conjunctival
blanching
▪ systemic: oral dryness, headache, orthostatic , hypotension, vasovagal
attacks.
▪ Contraindications: infants, MAO inhibitors users
Beta-adrenergic blockers
❑non-selective: timolol, levobunolol
❑ selective: betaxolol (beta 1 “cardioselective”)
❑ Uses: glaucoma
▪ Mechanism: reduce the formation of aqueous humor by the
ciliary body
❑Side effects: bronchospasm (less with
betaxolol), cardiac impairment
Carbonic Anhydrase Inhibitors
❑▪E.g. acetazolamide, methazolamide, dorzolamide, brinzolamide.
▪ Uses: glaucoma, cystoid macular edema, pseudo-tumour cerebri
▪ Mechanism: aqueous suppression
❑Side effects: myopia, GI upset, headache,
altered taste and smell, Na and K depletion, metabolic
acidosis, renal stone, bone marrow suppression “aplastic anemia”
❑Contraindication: sulpha allergy, digitalis users, pregnancy
Osmotic agents
▪ Dehydrate vitreous body which reduce IOP significantly
➢ E.G.
▪ Glycerol 50% syrup (cause nausea, hyperglycemia)
▪ Mannitol 20% IV (cause fluid overload and not used in
heart failure)

Prostaglandin Analogues
❑ E.g. latanoprost, bimatoprost, travoprost
▪ Uses: glaucoma
▪ Mechanism: increase uveoscleral aqueous outflow
❑▪ Side effects: darkening of the iris (heterochromia iridis),
lengthening and thickening of eyelashes, intraocular inflammation,
macular edema(happens when blood vessels leak into a part of the
retina)
 Anti-inflammatory

Corticosteroid NSAID

Corticosteroids
❑▪ Topical
▪ E.g. fluorometholone, prednisolone, dexamethasone, hydrocortisone
▪ Mechanism: inhibition of arachidonic acid release from phospholipids
by inhibiting phospholipase A2
▪ Uses: postoperatively, anterior uveitis, severe allergic conjunctivitis,
vernal keratoconjunctivitis, prevention and suppression of corneal
graft rejection, episcleritis, scleritis
❑▪ Side effects: susceptibility to infections, glaucoma, cataract, scleral
melting, skin atrophy
Corticosteroids
❑ Systemic:
▪ E.g. prednisolone, methylprednisolone
▪ Uses: posterior uveitis, optic neuritis, temporal
arteritis with anterior ischemic optic neuropathy
❑ Side effects:
▪ Local: posterior subcapsular cataract, glaucoma, central
serous retinopathy
▪ Systemic: suppression of pituitary-adrenal axis,
hyperglycemia, osteoporosis, peptic ulcer, psychosis

NSAIDs
❑ E.g. ketorolac, diclofenac, nepafenac
▪ Mechanism: inactivation of cyclo-oxygenase
▪ Uses: post-operatively, mild uveitis,
cystoid macular edema, preoperatively to prevent miosis
during surgery
❑ Side effects: stinging and burning.
Anti-allergy
▪ Avoidance of allergens, cold compress, lubrications
▪ Antihistamines (e.g.pheniramine, levocabastine)
▪ Decongestants (e.g. naphazoline, phenylepherine,
tetrahydrozaline)
▪ Mast cell stabilizers (e.g. cromolyn, nedocromil, olopatadine)
▪ NSAID (e.g. ketorolac)
▪ Steroids (e.g. fluorometholone, prednisolone)
▪ Drug combinations
Antibiotics
▪ Penicillins ▪ Cephalosporins ▪ Sulfonamides ▪ Tetracyclines ▪ Chloramphenicol
▪ Aminoglycosides ▪ Fluoroquinolones ▪ Vancomycin ▪ Macrolides

Antibiotics
▪ Used topically in prophylaxis - Eye drops or ointment containing an antibiotic
medication are placed in a newborn's eyes after birth(preand postoperatively) and
treatment of ocular bacterial infections.
▪ Used orally for the treatment of preseptal cellulitis
▪ e.g. amoxycillin with clavulonate , cefaclor
▪ Used intravenously for the treatment of orbital cellulitis
▪ e.g. gentamicin, cephalosporin,
vancomycin, flagyl
▪ Can be injected intravitrally for the treatment of endophthalmitis
Antibiotics
▪ Trachoma can be treated by topical and systemic tetracycline or erythromycin, or systemic
azithromycin.
▪ Bacterial keratitis (bacterial corneal ulcers) can be
treated by topical fortified penicillins, cephalosporins, aminoglycosides, vancomycin or
fluoroquinolones.
▪ Bacterial conjunctivitis is usually self limited but topical
erythromycin, aminoglycosides, fluoroquinolones, or chloramphenicol can be used

Antifungals
▪ Uses: fungal keratitis, fungal endophthalmitis
▪ Polyenes
▪ damage cell membrane of susceptible fungi
▪ e.g. amphotericin B, natamycin
▪ side effect: nephrotoxicity
▪ Imidazoles
▪ increase fungal cell membrane permeability
▪ e.g. miconazole, ketoconazole
▪ Flucytocine
▪ act by inhibiting DNA synthesis
Antivirals Ocular diagnostic drugs
▪ Acyclovir ▪ Fluorescein dye
▪ Available as drops or strips
Interact with viral thymidine kinase ▪ Uses: stain corneal abrasions,
(selective) applanation tonometry, detecting wound
Used in herpetic keratitis leak, NLD obstruction, fluorescein
angiography
▪ Trifluridine ▪ Caution:
More corneal penetration ▪ stains soft contact lens
Can treat herpetic iritis
Ocular diagnostic drugs
▪ Rose bengal stain
▪ Stains devitalized epithelium
▪ Uses: severe dry eye, herpetic keratitis

Local Anesthetics Local Anesthetics

▪ Topical ▪ Orbital infiltration
▪ E.g. propacaine, tetracaine
▪ peribulbar or retrobulbar
▪ Uses: applanation tonometry, goniscopy,
removal of corneal ▪ cause anesthesia and
foreign bodies, removal of sutures, examination akinesia
of patients who for intraocular surgery
cannot open eyes because of pain ▪ e.g. lidocaine, bupivacaine
▪ Adverse effects: toxic to corneal epithelium,
allergic reaction rarely
Complications of Topical Administration
▪ Mechanical injury from the bottle e.g. corneal abrasion
▪ Pigmentation: epinephrine-adrenochrome
▪ Ocular damage: e.g. topical anesthetics, benzalkonium
preservative
▪ Hypersensitivity: e.g. atropine, neomycin, gentamicin
▪ Systemic effect: topical phenylephrine can increase BP
Digitalis
• A cardiac failure drug
• Causes chromatopsia (objects appear yellow) with overdose

Chloroquines
▪ E.g. chloroquine, hydroxychloroquine
▪ Used in malaria, rheumatoid arthritis & SLE
▪ Cause vortex keratopathy (corneal verticillata) which is usually
asymptomatic but can present with glare and photophobia
▪ Also cause retinopathy (bull’s eye maculopathy)
Chlorpromazine
▪ A psychiatric drug
▪ Causes corneal punctate epithelial opacities, lens
surface opacities. Reversible with drug discontinuation
▪ Pigmentary retinopathy in high doses

Thioridazine
▪ A psychiatric drug
▪ Causes a pigmentary retinopathy after high dosage
Phenytoin
▪ An epilepsy drug
▪ Causes dosage-related cerebellar-vestibular effects:
▪ Horizontal nystagmus in lateral gaze
▪ Diplopia, ophthalmoplegia
▪ Vertigo, ataxia
▪ Reversible with the discontinuation of the drug