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Questions and Answers
How does latanoprost lower intraocular pressure (IOP)?
What is the most noticeable side effect of latanoprost on the iris?
Which of the following prostaglandins can increase eyelash length, darkness, and thickness?
What is a common adverse effect associated with brimonidine?
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Why is apraclonidine used only for short-term therapy?
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How do α2 agonists like brimonidine protect retinal neurons from death?
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Which medication does not cross the blood-brain barrier and does not promote hypotension?
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What is the main concern associated with long-term use of cholinesterase inhibitors like echothiophate?
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How does pilocarpine lower intraocular pressure in patients with open-angle glaucoma?
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Which medication is considered a second-line drug for open-angle glaucoma and can be used for emergency treatment of acute angle-closure glaucoma?
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What are the major side effects associated with pilocarpine use?
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Why is echothiophate reserved for patients who have responded poorly to preferred medications for glaucoma?
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How does dorzolamide (Trusopt) reduce intraocular pressure (IOP)?
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What distinguishes brinzolamide (Azopt) from dorzolamide in terms of side effects?
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What is the primary reason why oral carbonic anhydrase inhibitors are not the first choice for glaucoma treatment?
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In what way do carbonic anhydrase inhibitors primarily lower IOP?
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How does Netarsudil (Rhopressa) decrease IOP?
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What is a primary symptom of Allergic Conjunctivitis (AC)?
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Which class of drugs is considered a first-line choice for the treatment of glaucoma, along with β blockers?
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What is the primary method by which prostaglandin analogs lower intraocular pressure?
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Which procedure is used to promote unimpeded outflow of aqueous humor in cases where drugs are unable to reduce intraocular pressure adequately?
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Which condition results from the iris covering the trabecular meshwork, leading to a rapid increase in intraocular pressure?
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What is the primary mechanism of action of β blockers in lowering intraocular pressure?
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Why should nonselective β blockers be avoided in patients with asthma or COPD?
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What is the leading cause of preventable blindness in the United States?
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Which type of glaucoma is characterized by progressive optic nerve damage with eventual impairment of vision?
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What happens if the outflow from the anterior chamber is impeded?
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Where in the eye does aqueous humor circulate after being secreted?
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Which form of glaucoma may have normal intraocular pressure (IOP)?
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What is characteristic of primary open-angle glaucoma (POAG) in terms of symptoms?
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Which type of drugs prevent the release of inflammatory mediators like histamine from mast cells?
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How do histamine-1 (H1)-receptor antagonists provide relief to allergy symptoms?
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What is the mechanism of action of ocular decongestants like naphazoline and phenylephrine?
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Which drugs inhibit production of prostaglandins, leukotrienes, and thromboxane, making them highly effective?
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What is the primary function of mast cell stabilizers such as cromolyn and lodoxamide?
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Why are mast cell stabilizers like cromolyn and lodoxamide considered beneficial for allergies?
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In contrast to histamine-1 (H1)-receptor antagonists, what distinguishes the mechanism of action of nonsteroidal anti-inflammatory drugs (NSAIDs)?
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What distinguishes the effect of glucocorticoids like loteprednol from ocular decongestants like naphazoline on allergy symptoms?
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What is the primary function of topical cyclosporine ophthalmic emulsion (Restasis)?
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What is a common adverse effect associated with the use of ocular decongestants?
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Why are artificial tears considered safe for long-term use?
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What is the main purpose of using ocular decongestants?
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Which agent is primarily responsible for promoting the resumption of tear production in dry eyes due to inflammation?
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What distinguishes ocular decongestants from artificial tears in terms of their effects?
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What is the adverse effect commonly experienced with topical cyclosporine ophthalmic emulsion?
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What is a potential consequence of prolonged glucocorticoid therapy for eye disorders?
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Why is it important to consult with an ophthalmologist before prescribing glucocorticoids for eye disorders?
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What is a characteristic symptom of bacterial eye infections in terms of contagiousness?
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How does topical fluorescein help in assessing eye health?
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What is a potential adverse effect of intravenous administration of fluorescein for eye exams?
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Why should patients avoid using contact lenses when they have an eye infection?
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What is the main purpose of administering antiviral drugs like trifluridine and ganciclovir for eye infections?
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Why do patients need to be informed that bacterial and viral eye infections are contagious?
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Study Notes
Latanoprost and Intraocular Pressure
- Latanoprost reduces intraocular pressure (IOP) by increasing uveoscleral outflow of aqueous humor.
- The most noticeable side effect of latanoprost on the iris is increased pigmentation, leading to darker iris coloration.
- Prostaglandins that can increase eyelash length, darkness, and thickness include latanoprost and bimatoprost.
Brimonidine and Therapy Considerations
- Common adverse effect associated with brimonidine includes dry mouth and fatigue.
- Apraclonidine is used only for short-term therapy due to the rapid development of tolerance and side effects with prolonged use.
- α2 agonists like brimonidine protect retinal neurons by reducing intracellular cAMP levels, which lowers excitotoxicity.
Medications and Safety Profiles
- Timolol does not cross the blood-brain barrier and does not promote hypotension.
- Long-term use of cholinesterase inhibitors like echothiophate raises concerns about potential cataract formation.
Mechanisms of Other Glaucoma Treatments
- Pilocarpine lowers IOP by causing miosis (pupil constriction), facilitating aqueous humor outflow.
- Acetazolamide is considered a second-line drug for open-angle glaucoma and can be used in emergencies for acute angle-closure glaucoma.
- Major side effects associated with pilocarpine use include brow ache and paradoxical increase in IOP under certain conditions.
- Echothiophate is reserved for poorly responding glaucoma patients due to risk of serious adverse effects and systemic absorption.
Carbonic Anhydrase Inhibitors
- Dorzolamide (Trusopt) reduces IOP by inhibiting carbonic anhydrase, decreasing bicarbonate production, and thus aqueous humor secretion.
- Brinzolamide (Azopt) is less likely to cause local irritation compared to dorzolamide.
- Oral carbonic anhydrase inhibitors are not first-choice for glaucoma treatment due to systemic side effects.
- Carbonic anhydrase inhibitors primarily lower IOP by decreasing aqueous humor production.
Other IOP-Decreasing Mechanisms
- Netarsudil (Rhopressa) decreases IOP by enhancing aqueous humor outflow through multiple pathways.
- Allergic conjunctivitis (AC) commonly presents with itching and redness of the eyes.
- Prostaglandin analogs and beta-blockers are first-line treatments for glaucoma, working primarily by increasing trabecular outflow and reducing aqueous humor production, respectively.
Glaucoma Considerations
- Angle-closure glaucoma occurs when the iris obstructs the trabecular meshwork, leading to sudden IOP spikes.
- Nonselective β-blockers should be avoided in patients with asthma or COPD due to potential bronchoconstriction.
- Primary open-angle glaucoma (POAG) is characterized by a gradual loss of vision with often asymptomatic initial stages.
Ocular Medications and Mechanisms
- Antihistamines prevent the release of inflammatory mediators like histamine from mast cells.
- H1-receptor antagonists alleviate allergy symptoms through competitive inhibition at H1 receptors.
- Ocular decongestants like naphazoline and phenylephrine work as vasoconstrictors to reduce redness.
Mast Cell Stabilizers and NSAIDs
- Mast cell stabilizers such as cromolyn and lodoxamide prevent degranulation of mast cells, thus controlling allergy symptoms.
- Nonsteroidal anti-inflammatory drugs (NSAIDs) exert their effect by inhibiting cyclooxygenase enzymes, reducing pain and inflammation.
Glucocorticoids and Inflammation
- Glucocorticoids like loteprednol act by suppressing inflammation and immune response, unlike topical vasoconstrictors.
- Topical cyclosporine ophthalmic emulsion (Restasis) functions to increase tear production in dry eyes caused by inflammation.
- Common adverse effect of ocular decongestants includes rebound congestion with overuse.
Clinical Considerations and Eye Health
- Artificial tears are safe for long-term use since they do not contain preservatives that could harm the eye.
- Ocular decongestants primarily aim to alleviate redness and diminish blood vessel dilation.
- Topical cyclosporine can cause ocular burning or stinging upon application.
- Prolonged glucocorticoid therapy may lead to increased intraocular pressure, cataract formation, or other ocular complications.
Eye Infection Considerations
- Bacterial eye infections typically present with purulent discharge and can be highly contagious.
- Topical fluorescein is used to evaluate corneal injuries and health by highlighting damaged areas.
- Intravenous fluorescein administration may cause nausea and skin flushing as adverse effects.
- Contact lens use is contraindicated during eye infections due to the risk of complications and further irritation.
- Antiviral medications like trifluridine and ganciclovir target viral replication in eye infections.
- Patients must be warned about the contagious nature of bacterial and viral eye infections to prevent spread.
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Description
Test your knowledge on medications used in ophthalmology for conditions like glaucoma and ocular hypertension. Learn about the side effects and benefits of drugs such as apraclonidine, brimonidine, and timolol.
