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56 Cards in this Set
- Front
- Back
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Production of aqueous humor is regulated by what system and receptor?
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SYMPATHETIC - beta receptor
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SYMPATHETIC nervous system uses which NT and receptors
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NE - alpha and beta
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PARASYMPATHETIC nervous system uses which NT and receptors
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Ach - muscarinic (and nicotinic)
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Radial muscle is innervated by _ and _ receptor
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Sympathetic - alpha receptor
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Sphincter (ciliary muscle) is innervated by _ and _ receptor
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Parasympathetic - M3 receptor
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Dilation of the pupil is called _
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MIDRIASIS
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Constriction of pupil is called _
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MIOSIS
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Relaxation of ciliary muscle is innervated by _ and _ receptor
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Sympathetic - beta receptor
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MYDRIASIS (pupillary dilation) can be achieved by stimulating _ receptor and inhibiting _ receptor
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Alpha 1
M3 |
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Relaxation/paralysis of ciliary muscle with loss of ability to accomodate for near vision is called _
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CYCLOPLEGIA
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How do you obtain cycloplegia?
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Inhibiting M3 receptor
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What are the indications for production of MYDRIASIS
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- Fundoscopic exam
- Treatment of uveitis - preventing formation of synechiae - Dilating pupil before intraocular surgery - Red eye - available OTC - Diagnosis of errors of refraction (used with cycloplegic) - Other diagnostic procedures - angle block, retinoscopy |
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Adhesions between iris and lens are called _
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Synechiae
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Infection of iris, choroid and lens is called _
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Uveitis
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Which drug is alpha 1 agonist used to produce mydriasis
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PHENYLEPHRINE
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PHENYLEPHRINE CONTRAINDICATIONS
1. Phenylephrine is contraindicated in _ 2. Phenylephrine should be taken with caution in people with _ |
1. Infants, aneurysms and narrow angle glaucoma (increase IOP)
2. Diabetes, hypertension, CV disease, hyperthyroidism (reports of fatal ventricular arrhythmias and MI in elderly patients with preexisting cardiac disease) |
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All muscarinic antagonists are used for both _ when both effects are indicated
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Mydriasis and cycloplegia
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Name topical ophthalmic muscarinic antagonists
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Atropine
Scopolamine Tropicamide |
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Which muscarinic antagonist has longest duration of action - 7-10 days
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ATROPINE
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Which muscarinic antagonist has shortest duration of action - 6 hours
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TROPICAMIDE
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Which drugs are not used for mydriasis unless cycloplegia is also indicated
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Muscarinic antagonists
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Where does atropine come from ?
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Natural alkaloid found in Solanaceae plants
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What are the adverse effects of atropine?
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Dry mouth
Dry eyes Blurred vision Tachycardia - blocking vagal effect - unopposed sympathetic activation Constipation Anhidrosis Increased intraocular pressure |
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Patients who are experiencing adverse effects of atropine run risk of _
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Hyperthermia (because of anhidrosis)
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Atropine is contraindicated in patients with _ and should be used with caution in patients _
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GLAUCOMA - increases intraocular pressure
Patients predisposed to developing glaucoma (patients over 40) |
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Atropine causes _ CNS effects at therapeutic doses however causes _ at toxic doses and _ at extremely high doses
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Mild excitatory - therapeutic doses
Hallucinations + delirium - toxic doses Coma, respiratory arrest, death at extremely high doses |
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Atropine poisoning causes _
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Marked excitement, irritability, hyperactivity and increase in body temperature (all CNS effects), coupled with anhidrosis - "ATROPINE FEVER" - potentially fatal
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ATROPINE has additive adverse effects if combined with other antimuscarinic drugs - such as _
Also has additive CNS effects with _ |
Antihistamines
Phenothiazines Tricyclic antidepressants Amantadine MAOI's ALCOHOL |
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What kind of glaucoma is a medical emergency initially treated with drugs but eventually requiring surgical correction
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Acute/angle closure glaucoma
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Which type of glaucoma is most common type caused by lack of outflow of aqueous humor
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Chronic/open angle glaucoma
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Primary open angle glaucoma occurs due to degenerative changes in _
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Trabecular meshwork and connective tissue of Schlemms canal
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Primary angle closure glaucoma occurs due to anatomic or physiologic abnormalities of _ that predispose to _ often in patients with _ . Increased _ pressure also bows iris forward and occludes _
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1. Tissue and anterior chamber
2. Blockage of outflow channel by iris root 3. Hyperopia 4. Posterior chamber 5. Trabecular meshwork |
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Which drugs considered first line treatment for glaucoma?
What is the mechanism of action |
Beta blockers
Lower IOP by decreasing production of aqueous humor |
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Can beta blockers cause toxicity?
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Can be absorbed in amounts sufficient to cause systemic effects (most important on heart and lungs)
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Which topical beta blocker is used most for treatment of glaucoma
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TIMOLOL
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Epinephrine and Dipivefrin are indicated for treatment of _
What is the mechanism of action? Which receptor mediates this? Those drugs can be coupled with _ |
1. Open angle glaucoma
2. Decrease IOP by increasing drainage of aqueous humor 3. Alpha 4. Beta blocker |
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Prodrug form of EPI is called _
Is it often used? It is highly _ soluble and readily penetrates cornea |
DIPIVEFRIN
RARELY used Lipid |
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Name two direct acting alpha 2 agonists
Mechanism of action? What are they used for? What are the side effects? |
Apraclonidine
Brimonidine 2. Mechanism of action unclear 3. Short term treatment of refractory open angle glaucoma 4. Side effects - dry mouth, dry nose, headaches, others |
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MUSCARINIC AGONISTS IN GLAUCOMA TREATMENT
1. Cause _ by contracting iris sphincter muscles - decrease IOP, increase iris/cornea angle 2. Cause _ by contraction of ciliary muscle - decrease IOP - allow access of aqueous humor to canal of Schlemm |
1. MIOSIS
2.ACCOMODATION for near vision |
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Which drug has been largely replaced by beta blockers in treatment of open angle glaucoma
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PILOCARPINE
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PILOCARPINE is indicated for _
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Emergency treatment of acute narrow angle (angle-closure) glaucoma
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MOA of PILOCARPINE
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Produces miosis and ciliary muscle contraction - decrease IOP
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Name two Ach esterase inhibitors
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Physostigmine (reversible) and Ecothiophate (irreversible)
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AchE inhibitors are indicated for treatment of _
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Acute glaucoma
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Are AchE inhibitor drug of choice for acute glaucoma
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NOT drug of choice
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Mechanism of action of AchE inhibitors in treatment of glaucoma?
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Increase Ach --> cause miosis and ciliary muscle contraction --> decreases IOP
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Adverse effects of AchE inhibitors
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Cataracts with chronic use, at high doses causes CNS stimulation can lead to convulsions followed by respiratory and CV depression
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In intial treatment of acute glaucoma combination of which drugs should be given?
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Pilocarpine + Physostigmine
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Name Ach agonists
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Ach
Carbachol Pilocarpine |
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CARBACHOL
1. What is it used for? 2. Is it selective towards muscarinic receptors? |
1. Produces miosis for surgery (iridectomy)
2. NON selective - stimulates both muscarinic and nicotinic receptors |
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ACH
1. What is it used for? 2. Is it selective towards muscarinic receptors |
- LIMITED USE to achieve miosis for ophthalmic surgery only - rapidly destroyed by cholinesterases
- NON SELECTIVE - stimulates both muscarinic and nicotinic receptors |
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Which drug is used in transdermal patch worn behind ear to prevent motion sickness
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SCOPOLAMINE - gradual continuous release of drug within 3 days
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1. What is the mechanism of action of SCOPOLAMINE
2. What are the side effects? |
1. Possibly vomitting center in medulla or peripherally on vestibular apparatus
2. Significant SEDATION and dry mouth, potential withdrawal symptoms when removed especially if used for more then 3 days |
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HORNERS SYNDROME - typically unilateral interruption of _ and causes _
2. Nerve lesions cause nerve degeneration _ and leave _ intact |
1. Sympathetic innervation of face - causes miosis, ptosis, anhidrosis on affected side
2. Distally - postganglionic intact |
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_ and _ (indirect sympathetic agonists) block reuptake of NE thus enhancing sympathetic effects
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Cocaine and tricyclic antidepressants
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In HORNERS SYNDROME if indirect sympathomimetics will not dilate abnormally constricted pupil but phenylephrine does this lesion is _
If lesion responds to both dilation by phenylephrinea and cocaine the lesion is _ |
POSTGANGLIONIC
PREGANGLIONIC - postganglionic fibers and their catecholamine stores are intact |
