ketotifen, drug-eluting contact lens

Action and Spectrum

Actions and Spectrum: 

Actions: 

ketotifen blocks the effects of histamine, a chemical released during allergic reactions that causes itching, redness, and other allergy symptoms. By acting as an antihistamine, ketotifen helps to alleviate these allergic symptoms. 

The drug-eluting contact lens is designed to release ketotifen gradually over an extended period. This sustained drug release ensures a continuous therapeutic effect, providing long-lasting relief from allergy symptoms.  

Spectrum: 

ketotifen has a broad spectrum of action, making it effective against various allergens that can trigger allergic eye conditions. It can relieve allergens such as pollen, pet dander, dust mites, and mold spores.

Drug Interaction

Adverse Reaction

Frequency defined 

1-10% 

Eye irritation (≥1%) 

Instillation site irritation (≥1%) 

Eye pain (≥1%) 

Frequency Not Defined 

Corneal infections 

Corneal ulceration 

Black Box Warning

Black Box Warning: 

None 

Contraindication / Caution

Contraindication/Caution: 

Contraindication 

• Allergy 
• Methemoglobinemia 

Caution 

• Sensitivity & irritation 
• Eye contact 
• Pregnancy 
• Drug interactions 

Pregnancy / Lactation

Pregnancy consideration:  

No adequate data studies are performed on pregnant women. 

Breastfeeding warnings:  

Exercise caution while administering the drug to the nursing mother. 

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: 

ketotifen is an antihistamine that blocks the effects of histamine, a chemical mediator involved in allergic reactions. It selectively inhibits specific histamine receptors (H1 receptors) and stabilizes mast cells, thereby reducing the release of histamine and other inflammatory mediators.  

Pharmacodynamics 

ketotifen has been shown to stabilize mast cells involved in the allergic response. Stabilizing these cells prevents the release of histamine and other allergic mediators, thereby reducing the allergic response. The localized delivery of ketotifen through the drug-eluting contact lens helps alleviate the symptoms associated with allergic eye conditions, such as itching, redness, and watering. By blocking histamine and reducing inflammation, ketotifen provides relief from these symptoms.  

Pharmacokinetics 

Absorption 

The drug is directly absorbed through the conjunctiva and cornea into the ocular tissues, providing localized therapeutic effects. 

Distribution 

After absorption, ketotifen is distributed within the ocular tissues, where it exerts its pharmacological actions. The drug remains primarily localized to the eye, minimizing systemic exposure. 

Metabolism 

ketotifen undergoes hepatic metabolism, primarily through cytochrome P450 enzymes. However, since the drug-eluting contact lens provides localized delivery, the extent of systemic metabolism is expected to be minimal. 

Elimination and Excretion 

ketotifen and its metabolites are primarily eliminated through the bile and feces, with only a tiny portion excreted in the urine. The elimination half-life of ketotifen is approximately 12 hours in humans. 

Adminstartion

Administration: 

Maintain proper hygiene and care for the drug-eluting contact lens. Clean and disinfect the contact lens as instructed by your eye care professional or according to the specific product guidelines. 

Replacement Schedule: Follow the recommended replacement schedule for the drug-eluting contact lens. Dispose of the contact lens according to the recommended frequency to ensure continued efficacy and safety. 

Patient Information Leaflet

Patient information leaflet 

Generic Name: ketotifen, drug-eluting contact lens 

Why do we use ketotifen, a drug-eluting contact lens? 

Using ketotifen in a drug-eluting contact lens, such as Acuvue Theravision with ketotifen, offers several benefits for individuals with allergic eye conditions. 

ketotifen is an antihistamine that helps alleviate the symptoms associated with allergic eye conditions, such as itching, redness, and watering.