Pharmacology of Drugs Used For Glaucoma Flashcards
What drugs may be administered systemically to treat acute glaucoma?
CA inhibitors - Acetazolamide, Methazolamide (note suffix -zolamide)
What is the first-line drug for treatment of acute, closed-angle glaucoma?
Acetazolamide (CA inhibitor). If pressure remains high after one hour, an osmotic agent may be administered
What is the MOA of muscarinic agonists to treat glaucoma?
Increase outflow via the conventional/trabecular pathway by contracting the ciliary muscles to induce miosis (pupil constriction)
What carbonic anhydrase inhibitors are topically given to treat glaucoma?
Dorzolamide, Brinzolamine (note suffix -zolamide)
Why is apraclonidine only used for acute treatment?
Patients develop tachyphylaxis. This is similar to drug tolerance, but occurs more quickly. Patients between unresponsive to therapy.
What parasympathomimetic drugs may be used to treat glaucoma?
Pilocarpine, Carbachol
What are the osmotic agents used to treat glaucoma?
Mannitol, Glycerin, Isosorbide, Urea
What are the clinical indications for osmotic agents in treating glaucoma?
Acute, closed-angle glaucoma and malignant glaucoma
Through what two methods can aqueous humor flow out of the eye?
Conventional and unconventional pathways.
Describe the inflow of aqueous humor.
Produced by ciliary processes in the posterior chamber, flows around the lens and pupil into the anterior chamber
What ADRs are associated with pilocarpine and carbachol?
These are muscarinic agonists associated with ocular irritation, dimness of vision, myopia (nearsightedness), headache, retinal detachment
Through what processes can glaucoma treatment be targeted?
Decrease inflow or increase outflow through the conventional/unconventional pathways
True/False. Beta-blockers have no known ADRs when used for glaucoma treatment.
False. Beta-blockers have no local ADRs, but may cause depression, confusion, dry mouth, impotence, and fatigue.
What classes of drugs may be used to reduce aqueous humor inflow?
Beta-blockers, alpha agonists, carbonic anhydrase inhibitors
What is the only class of drugs that may be administered systemically to treat glaucoma?
Carbonic Anhydrase Inhibitors
In this outflow pathway, aqueous humor is reabsorbed by ciliary muscles.
Unconventional (Uveoscleral) Pathway
What are the contraindications for the use of beta-blockers in treating patients with glaucoma?
Asthma, COPD, bradycardia, heart failure. Blocking B2 receptors will cause bronchoconstriction and decreased HR
Metallic taste, paresthesias, hypokalemia, and metabolic acidosis are associated with what drug class used to treat glaucoma?
Carbonic Anhydrase Inhibitors
How does open-angle glaucoma differ from closed-angle?
Open-angle glaucoma is a chronic process due to issues with aqueous humor outflow. In open-angle glaucoma, the Iridocorneal angle is normal.
What alpha2 agonists are used to treat glaucoma?
Apraclonidine, Brimonidine. Note the suffix -nidine
What is the MOA of osmotic agents in treating glaucoma?
Make plasma hypertonic to draw water from vitreous humor, decrease aqueous humor production, and decrease intraocular pressure
What are the contraindications for Brimonidine?
Children under 2yo due to CNS depression
Where is aqueous humor produced?
By epithelium of ciliary processes in the eye
True/False. Carbachol is more effective than pilocarpine in treating glaucome.
False. Pilocarpine is more effective than Carbachol, but neither are first-line agents.
These drugs are first-line for treatment of glaucoma, with minimal systemic side effects.
Prostaglandin analogs
Bimatoprost, latanoprost, tafluprost are all what type of drug?
Prostaglandin analogs - all have the work “prost” in the name
Allergic reactions, blurry vision, bradycardia, decreased BP, and insomnia are ADRs associated with what medications used to treat glaucoma?
Alpha2 agonists - Apraclonidine, Brimonidine
Describe the conventional pathway of aqueous humor outflow.
Into the trabecular meshwork, through Schlemm’s canal, and into the venous system
What is the MOA of prostaglandins to treat glaucoma?
Increase outflow via the nonconventional/uveosclearal pathway
What ADRs are associated with prostaglandin analogs?
Conjunctival hyperemia, hyperpigmentation of skin, eyelash growth, darkening of the iris
True/False. Closed-angle glaucoma is an acute process that is considered a medical emergency.
True. Close-angle glaucoma results from pupillary or non-pupillary block.
This Beta Blocker is the most ineffective in treating glaucoma due to its selectivity for B1 receptors.
Betaxolol
What symptoms characterize glaucoma?
Retina ganglion cell death, vision problems and blindness, increased cup/disc ratio, increased intraocular pressure (not always)
