The goal in treatment of AACG is to reduce IOP. Medical management is the first step. A prompt reduction in IOP using topical and systemic medication decreases the duration of elevated IOP and the potential for visual field loss. IOP reduction is accomplished via suppression of aqueous humor production, eliminating pupillary block, and reversing inflammation. As with any medical intervention, intimate knowledge of the drugs, their indications, contraindications, and potential side effects can aid the physician in providing the best treatment and a favorable outcome.
Drug Category: Carbonic anhydrase inhibitors
These are first-line agents that should be used immediately during the initial intervention. They reduce bicarbonate production in the ciliary epithelium and therefore decrease aqueous formation.
| Drug Name | Acetazolamide (Diamox) |
|---|---|
| Description | Reduces rate of aqueous humor formation by direct inhibition of enzyme carbonic anhydrase (CA) on secretory ciliary epithelium, causing, in turn, a reduction in IOP. More than 90% of CA must be inhibited before IOP reduction can occur. May reduce IOP by 40-60%. Effects are seen in about an hour, they peak in 4 h, and trough in about 12 h. Derived chemically from sulfa drugs. If one form is not well tolerated, another form may be better or lower dose of the drug may better tolerated. IV administration of this medication may be used for rapid relief of increased IOP. A beneficial effect occurs when used with miotics or mydriatics. |
| Adult Dose | 500 mg IV stat, followed by 500 mg PO |
| Pediatric Dose | 5-10 mg/kg/dose IV/IM, then 0-15 mg/kg/d PO divided q6-8h |
| Contraindications | Documented hypersensitivity; hepatic disease; severe renal disease; adrenocortical insufficiency; severe pulmonary obstruction |
| Interactions | Can decrease therapeutic levels of lithium and alter excretion of drugs (amphetamines, quinidine, phenobarbital, salicylates) by alkalinizing urine |
| Pregnancy | C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus |
| Precautions | Patients with impaired hepatic function may go into coma; may cause substantial increase in blood glucose level in some diabetic patients |
| Drug Name | Methazolamide (Neptazane) |
|---|---|
| Description | Reduces aqueous humor formation by inhibiting enzyme carbonic anhydrase, which results in decreased IOP. |
| Adult Dose | 50-100 mg PO bid/tid |
| Pediatric Dose | Not established |
| Contraindications | Documented hypersensitivity; renal impairment |
| Interactions | May increase toxicity of salicylate, digoxin; coadministration with other diuretics may induce hypokalemia; decreases effects of lithium and alter excretion of other drugs by alkalinizing urine |
| Pregnancy | C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus |
| Precautions | Caution in respiratory acidosis and diabetes mellitus; impairs mental alertness and/or physical coordination; hematuria, glycosuria, polyuria, hepatic insufficiency, bone marrow suppression, thrombocytopenia/purpura, agranulocytosis, urticaria, pruritus, and rash may occur |
Drug Category: Beta-adrenergic blockers
These agents may lower IOP via their suppression of aqueous humor production and probably not through any affects on the pupil.
| Drug Name | Timolol (Timoptic, Timoptic XE) |
|---|---|
| Description | Reduces elevated and normal IOP by reducing aqueous humor production or possibly the outflow. |
| Adult Dose | 1 gtt of 0.25% or 0.5% solution in affected eye(s) bid; if IOP is maintained at satisfactory levels, reduce dosage to 1 gtt qd in affected eye(s) |
| Pediatric Dose | Not established |
| Contraindications | Documented hypersensitivity; bronchial asthma; sinus bradycardia; second- and third-degree AV block; severe chronic obstructive pulmonary disease; overt cardiac failure; cardiogenic shock |
| Interactions | May cause bradycardia and asystole when used in combination with systemic beta-blockers (may cause additive effects) |
| Pregnancy | C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus |
| Precautions | Product may have sulfites, which may cause allergic-type reactions in susceptible patients; may exacerbate or precipitate heart block, asthma, chronic obstructive pulmonary disease, mental changes (especially in the elderly persons) |
| Drug Name | Carteolol (Ocupress) |
|---|---|
| Description | Nonselective beta-adrenergic receptor. Blocks beta1- and beta2-receptors and has mild intrinsic sympathomimetic activity (ISA), with possibly fewer cardiac and lipid profile adverse effects. Precise mechanism by which carteolol decreases IOP is thought to be through reduction of aqueous formation. |
| Adult Dose | 1 gtt in affected eye(s) bid |
| Pediatric Dose | Not established |
| Contraindications | Documented hypersensitivity; congestive heart failure; asthma; cardiac conduction defects; breastfeeding |
| Interactions | May cause bradycardia and asystole when used in combination with systemic beta-blockers (may cause additive effects) |
| Pregnancy | C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus |
| Precautions | Product may have sulfites, which may cause allergic-type reactions in certain susceptible persons |
| Drug Name | Levobetaxolol (Betaxon) |
|---|---|
| Description | Selectively blocks beta1-adrenergic receptors with little or no effect on beta2-receptors. Reduces IOP by reducing production of aqueous humor. |
| Adult Dose | 1 gtt in affected eye(s) bid |
| Pediatric Dose | Not established |
| Contraindications | Documented hypersensitivity; bronchial asthma; severe chronic obstructive pulmonary disease; sinus bradycardia; second- and third-degree AV block; overt cardiac failure; cardiogenic shock |
| Interactions | May have additive systemic effects if patient is already on systemic beta-blockers |
| Pregnancy | C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus |
| Precautions | Beta-blockade may potentiate muscle weakness consistent with myasthenic symptoms; product may have sulfites, which may cause hypersensitivity reactions in susceptible persons |
| Drug Name | Levobunolol (AKBeta, Betagan) |
|---|---|
| Description | Nonselective beta-adrenergic blocking agent that lowers IOP by reducing aqueous humor production and may increase outflow of aqueous humor. Dosages of more than 1 gtt of 0.5% levobunolol twice daily have not been shown to be more effective. If IOP not at satisfactory level on this regimen, concomitant therapy can be instituted. However, do not administer 2 or more topical ophthalmic beta-adrenergic blocking agents simultaneously. |
| Adult Dose | 0.5% solution: 1-2 gtt in affected eye(s) qd 0.25% solution: 1-2 gtt in affected eye(s) bid Severe or uncontrolled glaucoma: 0.5% solution bid; closely monitor patient >1 gtt (0.5% levobunolol) bid not shown to be more effective; if IOP not at satisfactory level on this regimen, concomitant therapy can be instituted; do not administer 2 or more topical ophthalmic beta-adrenergic blocking agents simultaneously |
| Pediatric Dose | Not established |
| Contraindications | Documented hypersensitivity; bronchial asthma; severe chronic obstructive pulmonary disease; sinus bradycardia; second- and third-degree AV block; overt cardiac failure; cardiogenic shock |
| Interactions | May cause bradycardia and asystole when used in combination with systemic beta-blockers (may cause additive effects) |
| Pregnancy | C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus |
| Precautions | Beta-blockade may potentiate muscle weakness that is consistent with certain myasthenic symptoms (eg, diplopia, ptosis, generalized weakness); product may have sulfites, which may cause allergic-type reactions in certain susceptible persons |
Drug Category: Alpha-adrenergic agonists
These agents are used as adjunct agents to further decrease IOP secondary to their affect on aqueous humor production.
| Drug Name | Apraclonidine (Iopidine) |
|---|---|
| Description | Potent alpha-adrenergic agent selective for alpha2-receptors with minimal cross-reactivity to alpha1-receptors. Suppresses aqueous production. Reduces elevated, as well as normal, IOP whether or not accompanied by glaucoma. Apraclonidine is relatively selective alpha-adrenergic agonist that does not have significant local anesthetic activity. Has minimal cardiovascular effects. |
| Adult Dose | 1 gtt of 0.5% or 1% in affected eye(s) tid |
| Pediatric Dose | Not established |
| Contraindications | Documented hypersensitivity; patients on MAO inhibitors or have taken them in the past 14 d |
| Interactions | Monitor pulse and BP frequently when giving cardiovascular drugs; not for use concurrently with MAO inhibitors |
| Pregnancy | C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus |
| Precautions | May exacerbate or precipitate ocular irritation, topical sensitivity, vasovagal attack and optic nerve ischemia in patients with advanced glaucomatous optic neuropathy |
| Drug Name | Brimonidine (Alphagan, Alphagan-P) |
|---|---|
| Description | Selective alpha2 receptor that may reduce aqueous humor formation, may decrease inflow, or may increase uveoscleral outflow. |
| Adult Dose | 1 gtt in affected eye tid |
| Pediatric Dose | Not established |
| Contraindications | Documented hypersensitivity; patients receiving MAO inhibitor therapy |
| Interactions | Coadministration with topical beta-blockers may further decrease IOP; tricyclic antidepressants may decrease effects of brimonidine; CNS depressants such as barbiturates, opiates, and sedatives may potentiate effects of brimonidine |
| Pregnancy | B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals |
| Precautions | May exacerbate or precipitate ocular irritation, topical sensitivity, vasovagal attack and optic nerve ischemia in patients with advanced glaucomatous optic neuropathy |
Drug Category: Corticosteroids
These agents reduce ocular inflammation thereby providing symptomatic relief and augmenting the affects of other medications.
| Drug Name | Prednisolone (AK-Pred, Econopred) |
|---|---|
| Description | Used in treatment of acute inflammations following eye surgery or other insults to the eye. In cases of bacterial infections, concomitant use of anti-infective agents is mandatory. If signs and symptoms do not improve after 2 d, reevaluate the patient. Dosing may be reduced, but advise patients not to discontinue therapy prematurely. |
| Adult Dose | Solution: 1-2 gtt of solution into conjunctival sac up to q1h during day and q2h at night prn When a favorable response observed, reduce dosage to 1 gtt q4h; further reduction in dosage to 1 gtt tid/qid may suffice to control symptoms Susp: Shake well before using; 1-2 gtt into conjunctival sac bid/qid; during initial 24-48 h, dosing frequency may be increased prn |
| Pediatric Dose | Not established |
| Contraindications | Documented hypersensitivity; viral, fungal, or tubercular skin lesions |
| Interactions | Decreases effects of salicylates and toxoids (for immunizations); phenytoin, carbamazepine, barbiturates, and rifampin decrease effects of corticosteroids |
| Pregnancy | C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus |
| Precautions | Caution in hyperthyroidism, osteoporosis, cirrhosis, nonspecific ulcerative colitis, peptic ulcer, diabetes, and myasthenia gravis |
Drug Category: Ophthalmic agents, miotic
These agents pull the peripheral iris tissue away from the trabecular meshwork helping to eliminate obstructed aqueous humor flow. They are ineffective during the initial period due to the ischemic paralysis of the iris. Miotics should be used after the immediate management and initial reduction of IOP.
| Drug Name | Pilocarpine (Pilagan, Pilocar, Pilostat) |
|---|---|
| Description | Patients may be maintained on pilocarpine as long as IOP is controlled and no deterioration in visual fields is present. May be used alone or in combination with other miotics, beta-adrenergic blocking agents, epinephrine, carbonic anhydrase inhibitors, or hyperosmotic agents to decrease IOP. Frequency of instillation and concentration are determined by patient's response. Individuals with heavily pigmented irides may require higher strengths. |
| Adult Dose | Solution: 1-2 gtt tid/qid Gel: Apply 0.5-inch ribbon in the lower conjunctival sac of affected eye(s) hs If another glaucoma medication being used hs, use gtt at least 5 min before gel |
| Pediatric Dose | Not established |
| Contraindications | Documented hypersensitivity; acute inflammatory disease of anterior chamber |
| Interactions | May be ineffective when used concomitantly with nonsteroidal anti-inflammatory agents |
| Pregnancy | C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus |
| Precautions | Caution in acute cardiac failure, peptic ulcer, hyperthyroidism, GI spasm, bronchial asthma, Parkinson disease, recent MI, urinary tract obstruction, and hypertension or hypotension |
Drug Category: Hyperosmotics
Hyperosmotic agents increase serum osmolarity and cause a fluid shift from the eye into the vascular space. The subsequent osmotic diuresis reduces IOP.
| Drug Name | Glycerin (Osmoglyn) |
|---|---|
| Description | Used in glaucoma to interrupt acute attacks. Reduces IOP through its diuretic effects. Adds to tonicity of blood until metabolized and eliminated by kidneys. Maximal reduction of IOP occurs 1 h after glycerin administration. The effect lasts approximately 5 h. |
| Adult Dose | 1-2 g/kg PO and repeat q5h prn; alternatively, 1 mL/kg PO as a 50% solution in juice |
| Pediatric Dose | Administer as in adults |
| Contraindications | Documented hypersensitivity; frank or impending acute pulmonary edema, anuria, severe dehydration, and severe cardiac decompensation |
| Interactions | None reported |
| Pregnancy | C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus |
| Precautions | Administer orally, never parenterally; for oral use only; avoid in acute urinary retention in preoperative period; continued use may result in weight gain; caution in hypervolemia, diabetes, severely dehydrated individuals, confused mental states, congestive heart disease, and cardiac, renal, or hepatic disease |
| Drug Name | Isosorbide (Ismotic) |
|---|---|
| Description | In the eyes, creates an osmotic gradient between plasma and ocular fluids. Induces diuresis by elevating osmolarity of glomerular filtrate, thereby hindering tubular reabsorption of water. May be used to interrupt an acute attack of glaucoma. Use when less risk of nausea and vomiting, compared with other oral hyperosmotic agents, is needed. |
| Adult Dose | 1.5 g/kg PO initially, followed by 1-3 g/kg PO bid/qid prn |
| Pediatric Dose | Not established |
| Contraindications | Documented hypersensitivity; anuria, severe dehydration, frank or impending acute pulmonary edema, and severe cardiac decompensation |
| Interactions | None reported |
| Pregnancy | C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus |
| Precautions | Use repetitive doses with caution, particularly in patients with diseases associated with salt retention |
| Drug Name | Mannitol (Osmitrol) |
|---|---|
| Description | Reduces elevated IOP when pressure cannot be lowered by other means. Initially assess for adequate renal function in adults by administering a test dose of 200 mg/kg IV over 3-5 min. Should produce a urine flow of at least 30-50 mL/h of urine over 2-3 h. In children, assess for adequate renal function by administering a test dose of 200 mg/kg IV over 3-5 min. Should produce a urine flow of at least 1 mL/h over 1-3 h. |
| Adult Dose | 1.5-2 g/kg IV as 20% solution (7.5-10 mL/kg) or as 15% solution (10-13 mL/kg) over a period as short as 30 min |
| Pediatric Dose | Not established |
| Contraindications | Documented hypersensitivity; anuria, severe pulmonary congestion, progressive renal damage, severe dehydration, active intracranial bleeding, and progressive heart failure |
| Interactions | May decrease serum lithium levels |
| Pregnancy | C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus |
| Precautions | Carefully evaluate cardiovascular status before rapid administration of mannitol since a sudden increase in extracellular fluid may lead to fulminating CHF; avoid pseudoagglutination, when blood given simultaneously, add at least 20 mEq of sodium chloride to each liter of mannitol solution; do not give electrolyte-free mannitol solutions with blood |
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