cysteamine ophthalmic

Action and Spectrum

Actions and Spectrum: 

cysteamine ophthalmic works by breaking down cystine, an amino acid that tends to accumulate in the cornea of cystinosis patients due to a cystine transport defect. cysteamine reacts with cystine, leading to the formation of cysteine and cysteine-cysteamine mixed disulfide. This conversion helps prevent cystine crystals accumulation in the corneal tissue.  

Spectrum of Activity:  

The spectrum of activity of cysteamine ophthalmic is limited to its effect on corneal cystine crystals in patients with cystinosis. It is specifically indicated for treating corneal cystine crystal deposits associated with cystinosis and is not intended for treating other eye conditions or diseases. 

cysteamine ophthalmic targets the pathophysiological process of cystine accumulation in the cornea, characteristic of cystinosis. Its activity is localized to the cornea and aims to reduce the progression of corneal damage caused by cystine crystals. 

Drug Interaction

Adverse Reaction

Frequency defined 

>10% 

Cystaran 

Redness 

Headache 

Sensitivity to light 

Eye pain/irritation 

Visual field defects 

Cystadrops 

Vision blurred 

Ocular hyperemia 

Eye pruritus 

Ocular deposits 

Eye pain 

Eye irritation 

Instillation site discomfort 

Lacrimation increased 

Black Box Warning

Black box warning: 

None 

Contraindication / Caution

Contraindications/caution: 

Contraindications: 

None 

Caution: 

• Allergic Reactions: Some individuals may be allergic or hypersensitive to cysteamine ophthalmic.  
• Eye Irritation: cysteamine ophthalmic can cause irritation, including redness, itching, burning, and stinging sensations.  
• Contact Lens Use: cysteamine ophthalmic should not be used while wearing contact lenses. If you wear contact lenses, it is recommended to remove them before applying the medication and wait at least 15 minutes before reinserting them. 

Pregnancy / Lactation

Pregnancy consideration: Insufficient data available 

Lactation: Excretion of the drug in human breast milk is 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: 

cysteamine works by reducing the buildup of cystine crystals in the cornea. It acts by breaking down cystine into cysteine and cysteine-cysteamine mixed disulfide. This conversion helps to prevent the accumulation of cystine crystals in the corneal tissue, thereby reducing the risk of corneal damage and preserving vision. 

Pharmacodynamics: 

• Reduction of Corneal Cystine Crystals: cysteamine ophthalmic acts locally in the eye to reduce the buildup of cystine crystals in the cornea. Cystinosis is characterized by a defect in cystine transport, leading to the accumulation of cystine crystals in various tissues, including the cornea. cysteamine helps break down cystine into cysteine and cysteine-cysteamine mixed disulfide. Reducing cystine concentration prevents the formation and deposition of cystine crystals in the cornea. This mechanism helps preserve corneal health and maintain visual function in patients with cystinosis. 
• Protection of Corneal Tissues: The reduction of cystine crystals in the cornea through cysteamine ophthalmic treatment helps protect corneal tissues from the damaging effects of crystal accumulation. Cystine crystals can lead to corneal erosions, opacities, and vision impairment. By preventing or reducing the buildup of these crystals, cysteamine ophthalmic helps maintain corneal transparency and visual acuity. 

Pharmacokinetics: 

Absorption 

cysteamine ophthalmic is applied topically as eye drops directly onto the ocular surface. It is expected to be absorbed through the cornea and reach the target tissues in the eye, including the cornea. 

Distribution 

The distribution of cysteamine ophthalmic in the body beyond the ocular tissues is limited since it is primarily intended for local action. It is expected to remain predominantly localized to the ocular surface and the cornea. 

Metabolism 

The metabolism of cysteamine ophthalmic needs to be extensively documented. However, cysteamine is believed to undergo enzymatic reactions within the ocular tissues, potentially involving cellular metabolism mechanisms. 

Elimination and Excretion 

The elimination pathway of cysteamine ophthalmic needs to be well-established in the literature. cysteamine and its metabolites are likely eliminated from the ocular tissues primarily through local mechanisms, such as tear turnover and drainage. 

Adminstartion

Administration: 

• Wash your hands thoroughly with soap and water before handling the eye drops. 
• Tilt your head back. 
• Using a clean finger, gently pull down your lower eyelid to create a small pocket. 
• Look up and allow the drop to fall into the space between the lower eyelid and the eye. 
• Be careful not to touch the dropper tip to the eyelids, surrounding areas, or any surface to avoid contamination of the solution. 

Patient Information Leaflet

Patient information leaflet 

Generic Name: cysteamine ophthalmic 

Why do we use cysteamine ophthalmic? 

cysteamine ophthalmic is primarily used to treat corneal cystine crystal deposits in patients with cystinosis, an inherited metabolic disorder. Here are the primary uses of cysteamine ophthalmic: 

• Cystinosis: cysteamine ophthalmic is specifically indicated for treating corneal cystine crystal accumulation in patients with cystinosis. Cystinosis is a rare genetic disorder characterized by the buildup of cystine crystals in various tissues, including the cornea. cysteamine ophthalmic helps reduce the accumulation of cystine crystals in the cornea, preserving corneal health and maintaining visual function.