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Action/Kinetics:
Exerts both beta-1- and beta-2-adrenergic blocking activity. Has minimal sympathomimetic effects, direct myocardial depressant effects, or local anesthetic action. Does not cause pupillary constriction or night blindness. The mechanism of the protective effect in MI is not known.
Peak plasma levels: 1-2 hr.
t
1/2: 4 hr. Metabolized in the liver. Metabolites and unchanged drug excreted through the kidney.
Also reduces both elevated and normal IOP, whether or not glaucoma is present; thought to act by reducing aqueous humor formation and/or by slightly increasing outflow of aqueous humor. Does not affect pupil size or visual acuity. For use in eye:
Onset: 30 min.
Maximum effect: 1-2 hr.
Duration: 24 hr.
Uses:
Tablets: Hypertension (alone or in combination with other antihypertensives such as thiazide diuretics). Within 1-4 weeks of MI to reduce risk of reinfarction. Prophylaxis of migraine.
Investigational: Ventricular arrhythmias and tachycardias, essential tremors.
Ophthalmic solution (Timoptic): Lower IOP in chronic open-angle glaucoma, selected cases of secondary glaucoma, ocular hypertension, aphakic (no lens) clients with glaucoma.
Ophthalmic gel forming solution: Reduce elevated IOP in open-angle glaucoma or ocular hypertension.
Contraindications:
Hypersensitivity to drug. Bronchial asthma or bronchospasm including severe COPD.
Special Concerns:
Use ophthalmic preparation with caution in clients for whom systemic beta-adrenergic blocking agents are contraindicated. Safe use in children not established.
Side Effects:
Systemic following use of tablets: See
Beta-Adrenergic Blocking Agents.
Following use of ophthalmic product: Few. Occasionally, ocular irritation, local hypersensitivity reactions, slight decrease in resting HR.
Laboratory Test Alterations:
BUN, serum potassium, and uric acid.
H&H.;
Drug Interactions:
When used ophthalmically, possible potentiation with systemically administered beta-adrenergic blocking agents.
How Supplied:
Gel forming solution: 0.25%, 0.5%;
Ophthalmic solution: 0.25%, 0.5%;
Tablet: 5 mg, 10 mg, 20 mg
Dosage
?Tablets
Hypertension.
Initial: 10 mg b.i.d. alone or with a diuretic;
maintenance: 20-40 mg/day (up to 80 mg/day in two doses may be required), depending on BP and HR. If dosage increase is necessary, wait 7 days.
MI prophylaxis in clients who have survived the acute phase.
10 mg b.i.d.
Migraine prophylaxis.
Initially: 10 mg b.i.d.
Maintenance: 20 mg/day given as a single dose; total daily dose may be increased to 30 mg in divided doses or decreased to 10 mg, depending on the response and client tolerance. If a satisfactory response for migraine prophylaxis is not obtained within 6-8 weeks using the maximum daily dose, discontinue the drug.
Essential tremor.
10 mg/day.
?Ophthalmic Solution (Timoptic 0.25% or 0.5%)
Glaucoma.
1 gtt of 0.25%-0.50% solution in each eye b.i.d. If the decrease in intraocular pressure is maintained, reduce dose to 1 gtt once a day.
?Ophthalmic Gel-Forming Solution (Timoptic-XE 0.25% or 0.5%)
Glaucoma.
1 gtt once daily.
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