bimatoprost / timolol

Action and Spectrum

Actions and spectrum: 

bimatoprost: 

• Action: bimatoprost is a prostaglandin analog that mimics the action of prostaglandin, a naturally occurring substance in the body. It primarily works by increasing the outflow of aqueous humor, the fluid inside the eye. By enhancing the drainage of fluid, bimatoprost helps to lower intraocular pressure (IOP), which is crucial in managing conditions like glaucoma. 
• Spectrum: bimatoprost is effective in reducing elevated intraocular pressure and is commonly used in the treatment of ocular hypertension and open-angle glaucoma. 

timolol: 

• Action: timolol is a non-selective beta-adrenergic receptor blocker. It works by reducing production of aqueous humor in the eye, thereby decreasing intraocular pressure. timolol achieves this by blocking beta receptors in the ciliary body, which is responsible for producing the aqueous humor. 
• Spectrum: timolol is effective in lowering intraocular pressure and is commonly used as a first-line treatment for open-angle glaucoma and ocular hypertension. 

Drug Interaction

Adverse Reaction

Frequency not defined 

Abdominal pain 

Allergic conjunctivitis 

Alopecia 

Angioedema 

Asthenia 

Atrioventricular block 

Blepharitis 

Blurred vision 

Bronchospasm 

Cardiac arrest 

Cerebral ischaemia 

Chest pain 

Cold extremities 

Conjunctival hyperaemia 

Corneal erosion 

Cystoid macular oedema 

Depression 

Diplopia 

Dry eyes 

Dysgeusia 

Dyspnoea 

Erythema 

Asthma exacerbation 

Eyelid erythema 

Eyelid pain 

Eyelid retraction 

Fatigue 

Headache 

Hypertension 

Hypotension 

Insomnia 

Keratitis 

Myalgia 

Nightmares 

Ocular irritation 

Ocular pruritus 

Palpitations 

Pruritus 

Ptosis 

Raynaud’s phenomenon
Rhinitis 

Sexual dysfunction 

Syncope 

Urticaria 

Visual disturbances 

Black Box Warning

Black Box Warning: 

There may not be a specific black box warning for the combination of bimatoprost and timolol. 

Contraindication / Caution

Contraindication/Caution: 

Contraindication: 

• Hypersensitivity or Allergy: The combination should be avoided in individuals with a known hypersensitivity or allergy to bimatoprost, timolol, or any other component of the formulation. 
• Asthma or COPD: timolol, a beta-blocker, can cause bronchospasm and worsen respiratory conditions. Therefore, the combination is generally contraindicated in individuals with a history of asthma or severe COPD. 
• Corneal Endothelial Cell Dystrophy: The combination may be contraindicated in individuals with certain corneal disorders, such as corneal endothelial cell dystrophy. 
• Macular Edema: Individuals with macular edema may be at an increased risk, and caution is advised in using the combination in such cases. 

Caution: 

• Cardiovascular Conditions: Caution is advised in individuals with a history of cardiovascular disease, including heart failure, bradycardia, and conduction abnormalities. timolol, a beta-blocker, can affect heart rate and conduction, and careful monitoring is necessary in patients with pre-existing cardiovascular conditions. 
• Pulmonary Conditions: Timolol may cause bronchospasm, especially in individuals with asthma or COPD. Patients with respiratory conditions should be closely monitored, and the medication may need to be used with caution or avoided. 
• Hyperthyroidism: Caution is advised in individuals with hyperthyroidism. Beta-blockers can mask symptoms of hyperthyroidism, such as tachycardia. Monitoring thyroid function is important in these cases. 
• Contact Lens Wearers: bimatoprost can cause changes in the color of the iris and eyelashes. Contact lens wearers should be cautious as the medication may affect the appearance of colored contact lenses. 

Comorbidities: 

• Diabetes: Diabetes is a common comorbidity, and patients with both glaucoma and diabetes may be prescribed the combination cautiously. timolol, a beta-blocker, can mask symptoms of hypoglycemia, and blood glucose levels should be monitored in diabetic individuals. 
• Thyroid Disorders: Patients with thyroid disorders, particularly hyperthyroidism, may have comorbid glaucoma. Beta-blockers, such as timolol, should be used with caution in individuals with hyperthyroidism. 
• Liver Impairment: Patients with glaucoma and coexisting liver impairment may need careful consideration when using the combination, as both bimatoprost and timolol are metabolized in the liver. 
• Psychiatric Conditions: Individuals with glaucoma may have comorbid psychiatric conditions, and healthcare providers should consider the potential impact of beta-blockers on mental health. 

Pregnancy / Lactation

Pregnancy consideration: pregnancy category: not assigned 

Lactation: excreted into human milk: unknown  

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: 

The combination of bimatoprost and timolol is a pharmacological treatment designed to reduce intraocular pressure (IOP) in patients with glaucoma or ocular hypertension. bimatoprost, a prostaglandin analog, enhances the outflow of aqueous humor from the eye, lowering IOP. timolol, a non-selective beta-adrenergic receptor blocker, decreases the production of aqueous humor.

The dual mechanism of action provides a synergistic effect, leading to a more comprehensive reduction in IOP than either component alone. bimatoprost also contributes to increased uveoscleral outflow. The combination is administered as eye drops, and its pharmacology aims to address the underlying causes of elevated IOP, mitigating the risk of optic nerve damage associated with glaucoma. Regular monitoring is essential to ensure efficacy and manage any potential side effects.  

Pharmacodynamics: 

• Prostaglandin Analog: bimatoprost is a prostaglandin analog that primarily acts on the prostaglandin receptors in the eye. It increases the outflow of aqueous humor, the fluid that nourishes the eye, by enhancing the uveoscleral outflow pathway. This results in a reduction of IOP, which is crucial in managing conditions like glaucoma. 
• Beta-Adrenergic Receptor Blocker: timolol is a non-selective beta-adrenergic receptor blocker. It reduces IOP by decreasing the production of aqueous humor in the ciliary body. By blocking beta receptors, timolol inhibits the formation of aqueous humor, further contributing to the overall reduction in intraocular pressure. 
• Synergistic Effect: The combination of bimatoprost and timolol provides a dual mechanism of action. bimatoprost increases aqueous humor outflow, while timolol decreases its production. The synergistic effect of these two actions leads to a more significant and comprehensive reduction in IOP than what each component could achieve individually. 
• Efficacy in IOP Reduction: The combined action of bimatoprost and timolol helps maintain IOP within the target range, preventing damage to the optic nerve and preserving vision in patients with glaucoma or ocular hypertension. 

Pharmacokinetics: 

Absorption: 

• bimatoprost: After topical ocular administration, bimatoprost is absorbed through the cornea. It undergoes hydrolysis to its biologically active form. 
• timolol: timolol is also absorbed through the cornea after topical administration. It is a non-selective beta-blocker. 

Distribution: 

• bimatoprost: bimatoprost distributes to the target tissues in the eye, where it exerts its effects on the prostaglandin receptors. 
• timolol: timolol is distributed to the anterior chamber of the eye, exerting its action on beta receptors in the ciliary body. 

Metabolism: 

• bimatoprost: bimatoprost undergoes metabolism in the liver, primarily through fatty acid chain beta-oxidation and N-demethylation. 
• timolol: timolol undergoes extensive hepatic metabolism, primarily through oxidation and conjugation. 

Excretion and Elimination Half-Life: 

• bimatoprost: Metabolites of bimatoprost are excreted in urine and feces. The elimination half-life of bimatoprost is short, and the majority of the drug is eliminated within a few hours. 
• timolol: Metabolites of timolol are excreted in urine. timolol has a longer elimination half-life compared to bimatoprost, and the dosing frequency may be influenced by this characteristic. 

Adminstartion

Administration: 

• Wash Hands: Wash hands thoroughly before handling the eye drops to prevent contamination. 
• Prepare: Shake the medication well before using, following the instructions on the product packaging. 
• Position: Tilt the head backward or lie down and look upward. 
• Pull Lower Eyelid: Using a clean finger, gently pull-down lower eyelid to create a small pocket. 
• Instill Drops: Hold the dropper directly over the eye, without touching the eyelid or surrounding areas. Administer the prescribed number of drops into the lower conjunctival sac. Avoid contact between the dropper tip and the eye or any other surfaces. 
• Close Eyes: Close the eyes gently for a few minutes, avoiding blinking or squeezing the eyelids. This allows the medication to spread evenly over the eye’s surface. 
• Repeat for the Other Eye: If directed to use the drops in both eyes, repeat the process for the other eye. 
• Replace Cap: Immediately replace the cap on the bottle to prevent contamination. 

Patient Information Leaflet

Patient information leaflet 

Generic Name: bimatoprost / timolol 

Pronounced: (Bye-ma-TOE-prost / TIM-oh-lol)  

Why do we use bimatoprost and timolol? 

The primary indication for the combination of bimatoprost and timolol is the treatment of open-angle glaucoma, a chronic condition characterized by increased intraocular pressure. Elevated intraocular pressure may lead to optic nerve damage and vision loss. The combination is prescribed to lower IOP and mitigate the risk of progression. Ocular hypertension refers to elevated intraocular pressure without the signs of optic nerve damage or visual field loss characteristic of glaucoma.

The combination is used to manage ocular hypertension and prevent the development of glaucoma in individuals at risk. The combination of bimatoprost and timolol provides a synergistic effect due to their distinct mechanisms of action. bimatoprost increases aqueous humor outflow, while timolol decreases its production. Together, they achieve a more significant reduction in intraocular pressure than either component alone.