Bimatoprost + Timolol
Allopathic
Medicines List
All Medicine
Indications
- Primary Indication:
- Treatment of elevated intraocular pressure (IOP) in patients with open-angle glaucoma or ocular hypertension who require additional lowering of IOP when monotherapy is insufficient.
- Additional Clinical Uses:
- May be used in patients inadequately controlled with either bimatoprost or timolol alone.
- Not indicated for acute angle-closure glaucoma.
Dosage & Administration
- Route: Topical ophthalmic solution (eye drops).
- Adult Dose:
- Instill 1 drop once daily in the affected eye(s), preferably in the evening.
- Do not exceed once daily dosing; twice daily or more frequent use may reduce efficacy.
- Pediatrics:
- Safety and efficacy in patients under 18 years have not been established.
- Elderly:
- No dose adjustment necessary.
- Renal/Hepatic Impairment:
- No dosage adjustment necessary; systemic exposure minimal.
- Administration Instructions:
- Remove contact lenses prior to administration; wait at least 15 minutes before reinsertion.
- Avoid contamination of the dropper tip.
- Wash hands before and after use.
Mechanism of Action (MOA)
- Bimatoprost: A synthetic prostamide analog that lowers IOP by increasing aqueous humor outflow via the uveoscleral and trabecular meshwork pathways through activation of prostaglandin FP and prostamide-sensitive receptors. It remodels the extracellular matrix, facilitating fluid drainage.
- Timolol: A non-selective beta-adrenergic receptor blocker that reduces aqueous humor production by the ciliary body, lowering intraocular pressure.
- Combined Effect: The combination provides additive IOP-lowering by both increasing outflow (bimatoprost) and decreasing production (timolol), resulting in more effective pressure reduction than either agent alone.
Pharmacokinetics
- Absorption: Minimal systemic absorption after ocular administration; systemic plasma levels generally low.
- Distribution: Localized primarily in ocular tissues; systemic exposure is limited.
- Metabolism:
- Bimatoprost metabolized locally to inactive metabolites; minimal systemic metabolism.
- Timolol undergoes hepatic metabolism primarily via CYP2D6.
- Elimination:
- Bimatoprost metabolites excreted renally.
- Timolol and metabolites excreted via urine and feces.
- Half-life:
- Bimatoprost systemic half-life ~45 minutes.
- Timolol plasma half-life approximately 4–5 hours.
Pregnancy Category & Lactation
- Pregnancy: Category C — Animal studies have shown adverse fetal effects; use only if benefits outweigh risks.
- Lactation: Unknown if excreted in breast milk; caution advised. Consider discontinuation of drug or breastfeeding.
Therapeutic Class
- Primary Class: Antiglaucoma combination agent
- Subclass: Prostaglandin analog + Non-selective beta-blocker
Contraindications
- Hypersensitivity to bimatoprost, timolol, or any component of the formulation.
- Patients with bronchial asthma, severe chronic obstructive pulmonary disease (COPD), or sinus bradycardia, second- or third-degree atrioventricular block, overt cardiac failure, or cardiogenic shock (due to beta-blocker effects).
- Use contraindicated in acute cardiac failure or severe pulmonary disease.
Warnings & Precautions
- Respiratory: Use caution in patients with pulmonary disease (asthma, COPD).
- Cardiovascular: Monitor patients with cardiac conduction disorders or heart failure.
- Ocular: Possible iris pigmentation changes, eyelash changes, ocular inflammation.
- Hypersensitivity: Discontinue if signs of hypersensitivity or severe ocular inflammation occur.
- Masking Hypoglycemia: Timolol may mask signs of hypoglycemia in diabetic patients.
- Systemic Absorption: Minimal but possible; monitor for systemic beta-blocker effects.
- Avoid abrupt withdrawal in patients with coronary artery disease.
Side Effects
- Common:
- Ocular hyperemia (redness)
- Eye irritation or discomfort
- Blurred vision
- Eyelash growth and darkening
- Dry eyes
- Cardiovascular:
- Bradycardia, hypotension (rare)
- Respiratory:
- Bronchospasm in susceptible patients
- Rare:
- Iris pigmentation changes (usually permanent)
- Eyelid skin pigmentation changes
- Headache
- Allergic reactions including rash, angioedema
Drug Interactions
- Concomitant use with other beta-blockers or calcium channel blockers may potentiate cardiovascular effects (e.g., bradycardia, hypotension).
- Caution when coadministered with CYP2D6 inhibitors (may increase timolol plasma levels).
- Avoid use with other prostaglandin analogs to prevent additive ocular effects.
- Beta-blockers may interact with insulin or oral hypoglycemics, masking hypoglycemia signs.
Recent Updates or Guidelines
- Guidelines emphasize fixed-combination therapy like bimatoprost + timolol for patients inadequately controlled on monotherapy to improve compliance and reduce preservative exposure.
- No major changes to indications or dosing.
- Recent formulations with preservative-free options developed to reduce ocular surface irritation.
Storage Conditions
- Store at 20°C to 25°C (68°F to 77°F).
- Protect from freezing and light exposure.
- Keep bottle tightly closed.
- Discard open bottles after 4 weeks.
- Keep out of reach of children.