Exam 6: Chapter 43- Drugs used to treat glaucoma and other eye disorders

Drug Class: Adrenergic Agents: table 43-4

-Actions: Cause pupil dilation, increased outflow of aqueous humor, vasoconstriction, relaxation of ciliary muscle -Uses: Lower IOP in open-angle glaucoma -Common adverse effects: Sensitivity to bright lights, conjunctival irritation, lacrimation -Serious adverse effects: Tachycardia, hypertension, diaphoresis, trembling, fainting; Block inner canthus for 3-5 minutes to prevent absorption via tear duct -CAUTION: w/clients with hypertension, DM, hyperthyroidism, CVD, arteriosclerosis and asthma

Drug Class: see table 43-5Beta-Adrenergic Blocking Agents

-Actions: Exact mechanism unknown; thought to reduce production of aqueous humor -Uses: Reduce IOP with chronic open-angle glaucoma There is no blurred vision/night blindness effects from these meds -Common adverse effects: Conjunctival irritation, lacrimation -Serious adverse effects: Bradycardia, hypotension, fainting, bronchospasm

Drug Class: Prostaglandin Agonists; see table 43-6

-Actions: Increase the outflow of aqueous humor -Uses: Reduce IOP in patients with chronic open-angle glaucoma not responding to other agents -Common and serious adverse effects: Conjunctival irritation, lacrimation, burning and stinging, eye pigment changes, increased eyelash growth -Wait 5 minutes after applying drops to wear contact lenses

Drug Class: Carbonic Anhydrase Inhibitors; table 43-2

-Actions: Inhibit the enzyme carbonic anhydrase, decreasing the production of aqueous humor -Uses: In conjunction with other medications to control IOP -Serious adverse effects: Electrolyte imbalance; dehydration; dermatologic, hematologic, neurologic reactions; confusion; drowsiness

Drug Class: Cholinergic Agents

-Actions: Produce strong contractions of the iris and ciliary body -Uses: Lower IOP by widening the angle to allow outflow of aqueous humor -Common adverse effects: Reduced visual acuity, conjunctival irritation, erythema, headache, pain, discomfort -Serious adverse effects: Diaphoresis, sweating, diarrhea, hypotension, bradycardia, bronchospasm, tremors -Other uses include counteracting the effects of mydriatic and cycloplegic agents after surgery or eye examinations.

Drugs Class: Osmotic Agents; TABLE 43-1

-Actions: Reduce volume of intraocular fluid -Uses: Reduce IOP in patients with acute narrow-angle glaucoma -Serious adverse effects: Thirst, nausea, dehydration, electrolyte imbalance, headache, circulatory overload -IV use: Do not administer if crystals present -Can be given IV, PO or topically -Mannitol used for reduction of IOP.

Which is a common adverse effect of cholinergic ophthalmic agents? A) Muscle tremors B) Reduced visual acuity C) Diarrhea D) Salivation

Answer: B Rationale: Reduced visual acuity is common with cholinergic agents, especially in the first 1 to 2 hours after instillation. Cholinergic agents often cause difficulty in adjusting quickly to changes in light intensity.

Which situation increases pressure within the eye? A) Pupil constriction B) Pupil dilation C) Administration of a miotic agent D) Dehydration

Answer: B Rationale: Pupil dilation causes the iris to push against the trabecular network, which decreases the normal flow of fluid around the eye, thus causing pressure to build up. Miotic agents act to contract the iris sphincter muscle, which causes the pupil to narrow. This causes a decrease in intraocular pressure. A decrease in fluid volumes in dehydration will decrease the amount of fluid in the eye and thus decrease intraocular pressure.

After placing ophthalmic drops, what is the correct procedure for administering a second ophthalmic medication at the same time? A) Immediately administer the second medication. B) Wait 1 hour to administer the second medication. C) Wait 2 hours to administer the second medication. D) Wait 5 minutes to administer the second medication.

Answer: D Rationale: If more than one ophthalmic drug is to be administered at about the same time, the administration of the different medicines should be separated by at least 5 minutes. This ensures that the first medicine is not washed away by the second, or that the second medication is not diluted by the first.

A family member reports that the patient has taken adrenergic agents more frequently than recommended. The nurse should observe for which systemic effect? A) Hypotension B) Drowsiness C) Excessive tears D) Tachycardia

Answer: D Rationale: Tachycardia is a systemic effect of this medication.

Drug Class: Diagnostic Agent

Drug: Fluorescein -Uses: diagnostic aid in identifying foreign bodies in the eye and abraded or ulcerated areas of the cornea, evaluates retinal vasculature for abnormal circulation -Stains pathologic tissues -Available in topical solution and strips, and in solution for injection into aqueous humor

Drug Class: Anticholinergic Agentssee table 43-7

-Actions: Relax smooth muscle of the ciliary body and iris to produce mydriasis and cycloplegia -Uses: To examine the interior of the eye, measure refraction, and rest the eye in inflammatory conditions -Common adverse effects: Sensitivity to bright light, conjunctival irritation, lacrimation, increase in IOP -Serious adverse effects: Increased IOP, dry mouth, blurred vision, tachycardia, urinary retention, flushed skin -These agents will cause an increase in IOP.

The eyeball has three layers of tissue:

-Corneoscleral coat—protective coat -Choroid—nutritive middle vascular layer -Retina—light-sensitive inner layer

Eye medications

-Cycloplegic and mydriatic medications dilate the eye before eye exams and surgery -Miotic medications constrict the eye -Use aseptic technique, prevent transfer of infection from one eye to another -Prevent corneal damage in comatose patients, and during anesthesia -Postoperatively, position the patient according to orders

Major Types of Glaucoma

-Glaucoma characterized by elevated intraocular pressure (IOP); caused by an increased production of aqueous humor or an outflow obstruction -Primary: -Closed-angle glaucoma: occurs when there is a sudden increase in IOP caused by mechanical obstruction in the iridocorneal angle in patients with narrow anterior chamber angles -Open-angle glaucoma: develops slowly over years as pathologic changes occur Secondary:results from previous eye injury or disease or cataract surgery

The cornea

-Outermost part of the eyeball -Transparent, allows light to enter -Lacks blood vessels -Diffused air provides oxygen to the cornea -Resistance to infections -Contains sensory fibers that transmit pain if damaged -Corneal abrasions are highly susceptible to infection. -Injury to corneal tissue is replaced by scar tissue -The eye receives nutrition from the aqueous humor.

Flow of Aqueous Humor

-Produced by the ciliary body, it bathes and feeds the lens -Flows between the lens and the iris into the anterior chamber of the eye -Drains through channels located near the cornea and the sclera -Drains into a meshwork that leads into Schlemm's canal and into the venous system of the eye -Abnormalities of the drainage system can lead to glaucoma. -Open-angle and closed-angle glaucoma—increased or decreased flow exists.

General Considerations for Topical Ophthalmic Drug Therapy

-Topical application -Safety and color-coding -Check which eye is being medicated -Proper administration -Wash hands, tilt patient's head back slightly -Administer near inner portion of eye -Have patient close eye for a minute after administration -Minimize systemic absorption of ophthalmic drops by compressing the lacrimal sac for 3-5 minutes after instillation -Wait 5 minutes if administering different drops -After teaching patient, ask for return demonstration -If more than one drug is to be administered at about the same time, separate the administration of the different medicines by at least 5 minutes.

Drug Class: Antibacterials

-Treat superficial eye infections -Prophylaxis against ophthalmia neonatorum -Frequent use should be avoided because of possibility of development of resistant organisms

Eye Medications (cont.)

-Use eye patches and shields properly -Prevent an increase in IOP by instructing patient to avoid heavy lifting, straining on defecation, coughing, or bending the head -Patient with both eyes patched will experience sensory deprivation -Speak before touching person with impaired vision -Provide emotional support

Drug Class: Cholinesterase Inhibitors

Drug: echothiophate iodide (Phospholine Iodide) -Actions: Prevents metabolism of acetylcholine resulting in increased cholinergic activity which decreases IOP -Uses: Treat open-angle glaucoma --RESERVED for use in pt who do not respond to cholinergic agents -Common adverse effects: Reduced visual acuity, conjunctival irritation, erythema, headache, lacrimation -Serious adverse effects: Diaphoresis, salivation, diarrhea, hypotension, bradycardia, tremors. Antidote: atropine

Drug Class: Antifungal Agents

Drug: natamycin (Natacyn) -Actions: Alters the cell wall of fungus causing death of the fungus -Give @1-2 hour intervals the first 3-4 days, then 1 drop every 3-4 hours; use 14-21 days -Uses: Effective against Candida, Aspergillus, and Fusarium infections -Common adverse effects: Sensitivity to bright light, blurred vision, lacrimation, redness -Serious adverse effects: Eye pain, worsening of symptoms -Given at 1- to 2-hour intervals for first 3 to 4 days, then one drop every 3 to 4 hours. Therapy continued for 14 to 21 days to treat fungal keratitis.

Drug Class: Antiviral Agents

Drugs: ganciclovir (Vitrasert), trifluridine (Viroptic) -Actions: Inhibit viral replication -Uses: Treat herpes simplex keratitis, treat recurrent infections -Common adverse effects: Visual haze, lacrimation, redness, burning, sensitivity to bright light -Serious adverse effects: Allergic reactions

Mydriasis

is the contraction of the dilator muscle and relaxation of the sphincter muscle, which causes the pupil to dilate.