timolol ophthalmic

Action and Spectrum

Actions and spectrum: 

Actions: 

• Reduction of Aqueous Humor Production: timolol ophthalmic works by reducing the aqueous humor production. By inhibiting the action of beta-adrenergic receptors in the ciliary body, timolol decreases the formation of aqueous humor, which helps to lower intraocular pressure. 
• Decreased Resistance to Aqueous Humor Outflow: timolol may also enhance the outflow of aqueous humor by reducing resistance in the trabecular meshwork, a drainage system in the eye. This facilitates the drainage of fluid and further aids in the reduction of intraocular pressure. 

Spectrum:  

• timolol ophthalmic is primarily used for the treatment of glaucoma and ocular hypertension, conditions characterized by elevated intraocular pressure. It is effective in lowering intraocular pressure in both open-angle glaucoma and closed-angle glaucoma. 

Drug Interaction

Adverse Reaction

Frequency defined 

>1% 

Cataract (4-10%) 

visual acuity Decreased (4-10%) 

Hypertension (4-10%) 

Itching (4-10%) 

Blurred vision (4-10%) 

Conjunctivitis (4-10%) 

Headache (4-10%) 

Infection (4-10%) 

>10% 

Stinging or Burning (38%) 

Frequency not defined 

Blepharitis 

Ocular pain 

Foreign body sensation 

Eyelid erythema 

Decreased corneal sensitivity 

Cystoid macular edema 

Choroidal detachment 

Photophobia 

Corneal fluorescein staining 

Ptosis 

Ocular irritation 

Keratitis 

Discharge (e.g., crusting) 

Dry eyes 

Blepharoptosis 

Diplopia 

Pseudopemphigoid 

Epiphora 

Conjunctival injection 

Retinal vascular disorder 

Black Box Warning

Black Box Warning: 

timolol ophthalmic does not have a black box warning. 

Contraindication / Caution

Contraindication/Caution: 

Contraindication: 

• Hypersensitivity: timolol ophthalmic is contraindicated in individuals who have a known hypersensitivity or allergy to timolol or any other component of the medication. Allergic reactions from mild to severe and may include symptoms such as rash, itching, swelling, or difficulty breathing. 
• Bronchial Asthma: timolol is contraindicated in patients with bronchial asthma, as beta-blockers can potentially induce bronchospasm and worsen respiratory symptoms in susceptible individuals. 
• Severe Chronic Obstructive Pulmonary Disease (COPD): timolol ophthalmic is contraindicated in patients with severe chronic obstructive pulmonary disease (COPD), as it may exacerbate respiratory symptoms and decrease lung function. 
• Sinus Bradycardia, Heart Block, or Cardiogenic Shock: timolol ophthalmic should be avoided in individuals with sinus bradycardia (slow heart rate), heart block, or cardiogenic shock, as beta-blockers can further decrease heart rate or worsen cardiovascular conditions. 
• Decompensated Cardiac Failure: timolol ophthalmic is contraindicated in patients with decompensated cardiac failure. Beta-blockers can exacerbate heart failure symptoms and may be harmful in this population. 
• Ophthalmic Infections: timolol ophthalmic should not be used in cases of untreated ophthalmic infections, as it can mask the signs and symptoms of the infection and potentially worsen the condition.

Caution: 

• Cardiovascular Conditions: timolol ophthalmic should be used with caution in patients with cardiovascular conditions such as hypertension, angina, or a history of myocardial infarction. Beta-blockers can affect heart rate and blood pressure, so close monitoring is necessary in these individuals. 
• Respiratory Conditions: Patients with mild to moderate chronic obstructive pulmonary disease (COPD) should use timolol ophthalmic with caution, as it can potentially worsen respiratory symptoms. Regular monitoring of lung function is important in such cases. 
• Diabetes: timolol ophthalmic may mask certain signs of low blood sugar levels, such as increased heart rate. Diabetic patients should carefully monitor their blood sugar levels while using timolol and inform their healthcare provider about any changes. 
• Thyroid Disorders: timolol ophthalmic can mask signs and symptoms of hyperthyroidism. Close monitoring of thyroid function is recommended in patients with known or suspected thyroid disorders. 
• Surgery: If you are scheduled for any surgery, including eye surgery, inform your healthcare provider about the use of timolol ophthalmic. timolol can interact with certain medications used during anesthesia and may cause adverse effects. 
• Contact Lens Use: timolol ophthalmic contains a preservative (benzalkonium chloride) which is absorbed by soft contact lenses. 
• Pediatric and Geriatric Use: The safety and efficacy of timolol ophthalmic in children and elderly patients have not been fully established.

Comorbidities: 

• Cardiovascular Conditions: Caution is needed in patients with cardiovascular conditions such as hypertension, angina, or a history of myocardial infarction. timolol can affect heart rate and blood pressure, so close monitoring is necessary. 
• Respiratory Conditions: timolol should be used with caution in mild to moderate COPD due to the potential for worsening respiratory symptoms. 
• Diabetes: Diabetic patients should monitor their blood sugar levels closely while using timolol, as it may mask certain signs of low blood sugar levels. 
• Thyroid Disorders: Close monitoring of thyroid function is recommended in patients with known or suspected thyroid disorders, as timolol can mask signs and symptoms of an overactive thyroid. 
• Surgery: Patients scheduled for surgery, including eye surgery, should inform their healthcare provider about the use of timolol. timolol can interact with certain anesthesia medications and may cause adverse effects. 

Pregnancy / Lactation

Pregnancy consideration: N/A 

Lactation: N/A  

Pregnancy category: 

• Category A: well-controlled and Satisfactory studies show no risk to the fetus in the first or later trimester. 
• Category B: there was no evidence of risk to the fetus in animal studies, and there were not enough studies on pregnant women.   
• Category C: there was evidence of risk of adverse effects in animal reproduction studies, and no adequate evidence in human studies must take care of potential risks in pregnant women.     
• Category D: adequate data with sufficient evidence of human fetal risk from various platforms, but despite the potential risk, and used only in emergency cases for potential benefits.   
• Category X: Drugs listed in this category outweigh the risks over benefits. Hence these categories of drugs need to be avoided by pregnant women.   
• Category N: There is no data available for the drug under this category. 

Pharmacology

Pharmacology: 

timolol ophthalmic belongs to the class of drugs known as non-selective beta-adrenergic receptor blockers. timolol ophthalmic works by blocking beta-adrenergic receptors in the eye. It primarily targets the beta-1 and beta-2 receptors, although it has some affinity for beta-3 receptors as well. By blocking these receptors, timolol reduces the effects of sympathetic stimulation on the eye, leading to decreased production of aqueous humor and lowered intraocular pressure.  

Pharmacodynamics: 

• Inhibition of Aqueous Humor Production: timolol blocks the beta-adrenergic receptors in the ciliary body of the eye, which reduces the production of aqueous humor. Aqueous humor is a fluid that nourishes the eye and maintains intraocular pressure. By inhibiting its production, timolol helps to lower intraocular pressure. 
• Increased Uveoscleral Outflow: timolol may enhance the outflow of aqueous humor through the uveoscleral pathway, which is an alternative drainage route for fluid leaving the eye. By facilitating this outflow, timolol further contributes to the reduction of intraocular pressure. 
• Reduction of Ocular Blood Flow: timolol can cause a decrease in ocular blood flow, primarily due to its beta-blocking activity. This effect may be beneficial in certain conditions where excessive ocular blood flow contributes to elevated intraocular pressure. 
• Stabilization of Intraocular Pressure: timolol helps to stabilize intraocular pressure by reducing fluctuations and maintaining a consistent level over time. This is particularly important in managing glaucoma and ocular hypertension, where elevated and unstable intraocular pressure can damage the optic nerve and thereby vision loss.

Pharmacokinetics: 

Absorption 

When applied topically as eye drops, timolol is absorbed through the cornea into the anterior chamber of the eye. It can also be systemically absorbed into the bloodstream, although the systemic exposure is significantly lower compared to oral administration 

Distribution 

timolol is distributed throughout the body, including systemic circulation, but its concentration in ocular tissues is higher due to local absorption. 

Metabolism 

timolol undergoes metabolism primarily in the liver, by the enzyme cytochrome P450 2D6 (CYP2D6). The metabolites formed have minimal beta-blocking activity. 

Elimination and excretion 

timolol and its metabolites are eliminated through renal excretion. The half-life of timolol ophthalmic is short, ranging from about 4 to 6 hours. 

Adminstartion

Administration: 

• Wash your hands thoroughly before handling the eye drops. 
• Tilt your head and look up towards the ceiling. 
• Hold the dropper close to the eye, but without touching it. 
• Squeeze the prescribed no. of drops into the pocket formed by the lower eyelid. Usually, one to two drops are used in the affected eye(s). 
• Close eyes for a few seconds to allow the medication to spread evenly across the eye surface. 
• Avoid blinking or squeezing the eye while the drops are being instilled. 
• Replace the cap on the drop bottle and store it according to the manufacturer’s instructions. 

Patient Information Leaflet

Patient information leaflet 

Generic Name: timolol ophthalmic 

Pronounced: (tye-moh-lol off-thal-mik)  

Why do we use timolol ophthalmic? 

• Open-angle Glaucoma: timolol is commonly prescribed as a first-line treatment for open-angle glaucoma, which is the most common form of glaucoma. It helps to lower intraocular pressure by reducing aqueous humor production and increasing its outflow. 
• Closed-angle Glaucoma: In some cases of closed-angle glaucoma, timolol may be used in combination with other medications or procedures to manage intraocular pressure.  
• Ocular Hypertension: Ocular hypertension refers to elevated intraocular pressure without optic nerve damage or vision loss. timolol may be prescribed to individuals with ocular hypertension to prevent the development of glaucoma. 
• Combination Therapy: timolol ophthalmic can be used in combination with other eye drops, such as prostaglandin analogs or carbonic anhydrase inhibitors, to achieve better control of intraocular pressure.