Carteolol is a long-acting, non-selective β-adrenergic antagonist (beta-blocker) that also possesses intrinsic sympathomimetic activity, meaning it can partially stimulate β-receptors while blocking them. By inhibiting both β₁ and β₂ adrenergic receptors, it is effective in reducing intraocular pressure (IOP), making it useful in the treatment of glaucoma, as well as in managing cardiovascular conditions such as hypertension. Carteolol was first patented in 1972 during the expansion of beta-blocker research aimed at developing safer and more efficient therapeutic agents, and it was later approved for medical use in 1980 after demonstrating clinical efficacy and tolerability; since then, it has been widely used due to its balanced pharmacological action, which provides therapeutic benefits while minimizing the risk of excessive cardiac suppression compared to purely antagonistic beta-blockers.
BRAND NAMES
Cartrol
Ocupress
Mikelan
Arteolol
MECHANISM OF ACTION
Carteolol is a non-selective beta-blocker that lowers intraocular pressure by blocking beta-adrenergic receptors in the eye’s ciliary body, reducing the production of aqueous humor
PHARMACOKINETICS
Absorption
Carteolol eye drops are partially absorbed through the cornea and conjunctiva, with peak effects within 1–2 hours and minimal systemic absorption.
Distribution
Carteolol is approximately 50–60% bound to plasma proteins and distributes mainly to the eye after topical administration, with low systemic levels.
Metabolism
Carteolol is partially metabolized in the liver by oxidative pathways, producing inactive metabolites. A significant portion of the drug remains unchanged and is excreted via the kidneys.
Excretion
Carteolol is mainly excreted unchanged in the urine, with a small portion eliminated as metabolites. Its renal clearance helps maintain low systemic levels after topical eye use.
PHARMACODYNAMICS
Carteolol lowers intraocular pressure by blocking beta receptors in the eye, reducing fluid production, with mild receptor activity to limit systemic effects.
ADMINISTRATION
Carteolol is usually given as eye drops, typically 1–2 drops in the affected eye(s) once or twice daily. Proper technique includes washing hands, avoiding contact with the eye, and gently closing the eyelid to reduce systemic absorption.
DOSAGE AND STRENGTH
Strength: 1% or 2% ophthalmic solution
Dosage: 1–2 drops in the affected eye(s) once or twice daily, depending on the patient’s intraocular pressure and response.
FOOD INTERACTIONS
Carteolol, when used as eye drops, has no known significant food interactions. Its effectiveness and absorption are not affected by meals or dietary intake.
DRUG INTERACTIONS
Other beta-blockers – Can increase additive effects, causing excessive lowering of heart rate or blood pressure.
Calcium channel blockers (e.g., verapamil, diltiazem) – May enhance bradycardia or heart block.
Antiarrhythmics – Increased risk of slow heart rate or conduction problems.
CONTRAINDICATIONS
Asthma or severe chronic obstructive pulmonary disease (COPD) – risk of bronchospasm
Sinus bradycardia, heart block, or cardiac failure – may worsen cardiac conditions
Hypersensitivity to carteolol or other beta-blockers
SIDE EFFECTS
Common side effects include:
Eye irritation, burning, or stinging
Blurred vision
Dry eyes
Tearing or redness
OVERDOSE
Excessive use may cause slow heart rate, low blood pressure, dizziness, or breathing difficulties. Immediate medical attention is required, with supportive care as needed.
TOXICITY
Toxicity is rare with eye drops but can occur if excessively absorbed systemically. It may lead to severe bradycardia, hypotension, heart block, or bronchospasm, especially in sensitive individuals or those with heart or lung conditions.
