Ocular Pharmacology

Beta-adrenergic and Muscarinic (M)

Which autonomic receptor subtypes are present on the corneal epithelium?

Beta-adrenergic

Which autonomic receptor subtype is present on the corneal endothelium?

Alpha-1 adrenergic

Which autonomic receptor subtype on the iris radial dilator muscle mediates mydriasis?

Muscarinic (M)

Which autonomic receptor subtype on the iris sphincter muscle mediates miosis?

Beta-adrenergic

Which receptor subtype on the trabecular meshwork modulates aqueous outflow dynamics?

Alpha-2 and Beta-2 adrenergic

Which autonomic receptor subtypes are present on the ciliary epithelium?

75% to 90%

What percentage of adrenergic receptors on the ciliary epithelium belong to the Beta-2 subtype?

cAMP-PKA pathway

Which intracellular pathway mediates aqueous humor production in the ciliary epithelium?

Muscarinic M3

Which receptor subtype on the ciliary muscle mediates accommodation and pulls on the scleral spur?

Topical (Drops/Ointment)

Which administration route is convenient, economical, and safe for anterior segment diseases but limited by lacrimal wash-out?

Subconjunctival / Sub-Tenon's

Which injection route provides prompt to sustained release for posterior uveitis and cystoid macular edema?

Intracameral (Anterior Chamber)

Which administration route delivers an immediate local effect during anterior segment surgery?

Intravitreal Injection / Implant

Which route places drug directly into the posterior segment, circumventing the blood-retinal barrier?

Nasolacrimal mucosa

Through which mucosal site does systemic absorption of topically applied eye drops primarily occur?

Local tissue injury, globe perforation, optic nerve trauma, CRAO/CRVO, and muscle trauma

What are four major risks associated with sub-Tenon's or subconjunctival injections?

Corneal endothelial toxicity and intraocular toxicity

What are two major risks associated with intracameral injections?

Retinal detachment, endophthalmitis, elevated IOP, and intraocular hemorrhage

What are four major risks associated with intravitreal injections?

Latanoprost

Which PGF2alpha prodrug analogue is hydrolyzed by corneal esterases and acts as a first-line glaucoma medication?

-prost

What is the characteristic drug name suffix for prostaglandin analogues?

FP receptor

Which cell-surface prostanoid receptor subtype is targeted by latanoprost and travoprost?

Gq/11-PLC-IP3-Ca2+ pathway

Which intracellular signaling pathway is activated upon FP receptor binding by latanoprost?

Matrix metalloproteinases (MMPs)

Induction of which enzymes by latanoprost degrades ciliary muscle extracellular matrix to increase uveoscleral outflow?

Open-Angle Glaucoma (OAG) and Ocular Hypertension (OHT)

What are the primary clinical indications for latanoprost?

Active intraocular inflammation and risk of cystoid macular edema

What are two primary contraindications or cautions for latanoprost?

Hypertrichosis, permanent iris hyperpigmentation, orbital fat atrophy, and conjunctival hyperemia

What are four characteristic local ocular side effects of prostaglandin analogues?

Once-daily night dosing

What is the standard dosing frequency and time of day for latanoprost?

Travoprost

Which PGF2alpha analogue increases uveoscleral outflow and is available in fixed combination with timolol?

Bimatoprost

Which synthetic prostamide analogue enhances both uveoscleral and conventional trabecular outflow?

Hypotrichosis of eyelashes

What non-glaucoma indication is approved for bimatoprost?

10 μg intracameral implant

In what sustained-release formulation is bimatoprost available for intraocular delivery?

Tafluprost

Which fluorinated PGF2alpha analogue is supplied in preservative-free single-dose droperettes?

Latanoprostene Bunod

Which dual-action prodrug releases nitric oxide to relax the trabecular meshwork alongside a latanoprost moiety?

Latanoprost + Netarsudil and Latanoprost + Timolol

What are two fixed drug combinations that contain latanoprost?

Travoprost + Timolol

What fixed drug combination contains travoprost?

Bimatoprost + Timolol

What fixed drug combination contains bimatoprost?

Timolol

Which non-selective beta-adrenergic antagonist is the prototypical topical beta-blocker for glaucoma?

-olol

What is the standard drug suffix for beta-adrenergic antagonists?

Non-pigmented Ciliary Body Epithelium

What is the target anatomical location of timolol?

Blunting adrenergic activation of the cAMP-PKA pathway to reduce aqueous production

What is the primary mechanism of action of timolol?

Asthma, severe COPD, sinus bradycardia, 2nd/3rd-degree AV block, and overt heart failure

What are five systemic contraindications to non-selective topical beta-blockers?

Bronchospasm, bradycardia, hypotension, depression, impotence, and fatigue

What are six systemic side effects of timolol?

Timolol + Dorzolamide, Timolol + Brimonidine, and Timolol + Latanoprost

What are three common fixed drug combinations containing timolol?

Betaxolol

Which cardioselective beta-1 adrenergic antagonist is safer for glaucoma patients with mild pulmonary disease?

Beta-1 receptors

Which receptor subtype is selectively blocked by betaxolol?

Lower incidence of pulmonary adverse effects

What is the primary clinical advantage of betaxolol over timolol?

Carteolol

Which non-selective beta-blocker possesses intrinsic sympathomimetic activity (ISA)?

Levobunolol

Which long-acting non-selective beta-blocker is administered once or twice daily for glaucoma?

Apraclonidine

Which ionized clonidine derivative is used short-term for post-surgical IOP spikes and to diagnose Horner's syndrome?

-nidine

What is the characteristic drug suffix for selective alpha-2 adrenergic agonists?

Presynaptic Gi-mediated reduction in cAMP

By what presynaptic mechanism does apraclonidine decrease aqueous production?

Reverses anisocoria due to denervation supersensitivity

How does apraclonidine aid in the diagnosis of Horner's syndrome?

Allergic follicular conjunctivitis, dry mouth, ocular blanching, and lethargy

What are four side effects of apraclonidine?

Brimonidine

Which lipophilic selective alpha-2 agonist easily penetrates the cornea to lower IOP?

Neonates and infants under 2 years of age

In which patient group is brimonidine strictly contraindicated?

CNS depression, apnea, and bradycardia

What life-threatening systemic side effects can brimonidine cause in infants?

Decreases aqueous synthesis and increases uveoscleral outflow

What is the dual outflow and production mechanism of brimonidine?

Brimonidine + Timolol and Brimonidine + Brinzolamide

What are two fixed drug combinations containing brimonidine?

Dorzolamide

Which topical carbonic anhydrase inhibitor inhibits Carbonic Anhydrase Isoform II?

-zolamide

What is the drug suffix for carbonic anhydrase inhibitors?

Non-pigmented ciliary body epithelium

Where is Carbonic Anhydrase Isoform II located in the eye?

Reduces HCO3- formation and active fluid transport into the anterior chamber

How do carbonic anhydrase inhibitors decrease aqueous production?

Known sulfonamide hypersensitivity and severe renal impairment

What are two contraindications for dorzolamide?

Ocular burning, stinging, bitter/metallic taste, and punctate keratitis

What are four side effects of topical dorzolamide?

Dorzolamide + Timolol

What fixed drug combination contains dorzolamide?

Brinzolamide

Which topical carbonic anhydrase inhibitor is formulated as a neutral pH suspension for better comfort?

Brinzolamide + Brimonidine

What fixed drug combination contains brinzolamide?

Acetazolamide

Which systemic (oral/IV) carbonic anhydrase inhibitor is used for acute angle-closure glaucoma crises?

Acute Angle-Closure Glaucoma crisis, pre-op IOP spike, and Pseudotumor Cerebri

What are three primary indications for acetazolamide?

Paresthesias, malaise, hypokalemia, kidney stones, and rare aplastic anemia

What are five systemic side effects of oral acetazolamide?

Methazolamide

Which oral carbonic anhydrase inhibitor has lower protein binding and a longer half-life than acetazolamide?

Netarsudil

Which Rho kinase inhibitor lowers trabecular outflow resistance by relaxing actin stress fibers?

-sudil

What is the drug suffix for Rho kinase (ROCK) inhibitors?

Trabecular Meshwork & Schlemm's Canal

What is the target anatomical location of netarsudil?

Relaxes actin stress fibers in trabecular meshwork

How does netarsudil alter the trabecular meshwork cytoskeleton?

Conjunctival hyperemia, subconjunctival hemorrhage, and cornea verticillata

What are three side effects of netarsudil?

Ripasudil

Which selective Rho kinase inhibitor is approved in Japan and used in Fuchs' dystrophy after Descemet stripping?

Netarsudil + Latanoprost

What fixed drug combination contains netarsudil?

Pilocarpine

Which direct-acting muscarinic agonist contracts the ciliary muscle to pull on the scleral spur?

-carpines

What is the drug suffix for direct-acting pilocarpine derivatives?

Opens trabecular meshwork spaces via ciliary muscle traction on scleral spur

How does pilocarpine increase aqueous outflow?

Ciliary spasm/brow ache, induced myopia, dark visual field, and retinal detachment

What are four ocular side effects of pilocarpine?

Diluted 0.05%–0.1% solution

What concentration of pilocarpine is used to diagnose Adie's tonic pupil?

Carbachol

Which dual direct muscarinic agonist and weak anticholinesterase causes intense miosis intraoperatively?

Echothiophate

Which irreversible organophosphate anticholinesterase is used in accommodative esotropia?

Positively charged quaternary ammonium

What chemical structure prevents echothiophate from easily penetrating systemic membranes?

Iris cysts and cataract formation

What are two characteristic ocular side effects of long-term echothiophate therapy?

Atropine

Which non-selective muscarinic antagonist produces prolonged mydriasis and cycloplegia for 7–14 days?

Competitively blocks muscarinic cholinergic receptors on iris sphincter and ciliary muscle

What is the mechanism of action of atropine?

Primary angle-closure glaucoma or narrow angles

What is a primary ocular contraindication for atropine?

Marked photophobia, blurred vision, prolonged cycloplegia, dry mouth, and flushing

What are five side effects of atropine?

Low-dose (0.01%) atropine

Which atropine regimen is used off-label to slow pediatric myopia progression?

Atropine + Phenylephrine

What fixed drug combination contains atropine?

Cyclopentolate

Which antimuscarinic agent is the standard pediatric cycloplegic with an onset of 25–75 minutes?

-olate

What is the drug suffix for cyclopentolate?

Transient stinging, photophobia, and CNS toxicity/hallucinations in children

What are three side effects of cyclopentolate?

Cyclopentolate + Phenylephrine

What fixed drug combination contains cyclopentolate?

Tropicamide

Which short-acting antimuscarinic is the standard office mydriatic with recovery in ~6 hours?

-amide

What is the drug suffix for tropicamide?

Tropicamide + Phenylephrine and Tropicamide + Hydroxyamphetamine

What are two fixed drug combinations containing tropicamide?

Phenylephrine

Which selective alpha-1 adrenergic agonist dilates the pupil without paralyzing accommodation?