Drug Guide
Timolol
Classification
Therapeutic: Antiglaucoma agent, Beta-blocker
Pharmacological: Beta-adrenergic receptor blocker
FDA Approved Indications
- Glaucoma (Open-angle glaucoma and ocular hypertension)
Mechanism of Action
Timolol decreases intraocular pressure by reducing aqueous humor formation via non-selective beta-adrenergic blockade in the ciliary body.
Dosage and Administration
Adult: Typically one drop in affected eye(s) twice daily. Adjust based on response and tolerance.
Pediatric: Use is not generally recommended for pediatric patients; consult specific pediatric guidelines.
Geriatric: Use with caution; start at lower doses due to potential cardiovascular and respiratory sensitivities.
Renal Impairment: No specific adjustment recommended, but monitor closely.
Hepatic Impairment: No specific adjustment; use with caution.
Pharmacokinetics
Absorption: Absorbed through conjunctiva; systemic absorption can occur.
Distribution: Widely distributed, crosses the blood-brain barrier.
Metabolism: Minimal hepatic metabolism.
Excretion: Renal excretion of unchanged drug.
Half Life: Approximately 4-5 hours.
Contraindications
- Hypersensitivity to timolol or other beta-blockers
- Reactive airway disease (e.g., asthma, COPD)
- Second- or third-degree AV block
- Sinus bradycardia
- Uncompensated heart failure
Precautions
- Use cautiously in patients with cardiac or pulmonary issues, diabetes (may mask hypoglycemia symptoms), or peripheral vascular disease.
Adverse Reactions - Common
- Transient burning and stinging in the eyes (Common)
- Blurred vision (Common)
- Ocular itching or redness (Common)
Adverse Reactions - Serious
- Bradycardia, hypotension (Rare)
- Bronchospasm and wheezing in susceptible individuals (Rare)
- Systemic effects such as fatigue, dizziness, or dizziness (Rare)
Drug-Drug Interactions
- Calcium channel blockers (e.g., verapamil, diltiazem) may enhance cardiovascular effects.
Drug-Food Interactions
N/ADrug-Herb Interactions
N/ANursing Implications
Assessment: Monitor ocular condition, intraocular pressure, and systemic cardiac and respiratory status.
Diagnoses:
- Risk for systemic systemic effects related to systemic absorption.
- Impaired comfort related to ocular irritation.
Implementation: Administer eye drops as prescribed, ensuring correct technique; instruct patients to avoid touching the dropper tip to the eye.
Evaluation: Assess intraocular pressure response and monitor for systemic adverse effects.
Patient/Family Teaching
- Do not touch the tip of the dropper to the eye or surrounding structures.
- Use only as prescribed.
- Report signs of systemic effects such as worsening breathing or heart rate issues.
- Use regular follow-up appointments to monitor eye pressure.
Special Considerations
Black Box Warnings:
- Potential for systemic absorption leading to severe bradycardia, hypotension, or bronchospasm.
Genetic Factors: N/A
Lab Test Interference: N/A
Overdose Management
Signs/Symptoms: Bradycardia, hypotension, bronchospasm, dizziness, fatigue.
Treatment: Supportive; administer atropine for bradycardia, medications for blood pressure support, and bronchodilators if bronchospasm occurs.
Storage and Handling
Storage: Store at room temperature, away from light and moisture.
Stability: Stable up to expiration date if properly stored.