Products
Eye drops containing the active ingredient N-acetylcysteine are no longer commercially available as finished drug products in many countries. They can be prepared in a pharmacy as an extemporaneous preparation.
Structure and properties
N-acetylcysteine (C5H9NO3, Mr = 163.2 g/mol) is -acetylated derivative of the amino acid cysteine with a free sulfhydryl group. It exists as a white crystalline powder or as colorless crystals and is readily soluble in water. Acetylcysteine smells of sulfur. This can be perceived when the vial is opened.
Effects
N-acetylcysteine has expectorant, cleansing and wound healing properties. It inhibits collagenase in the cornea, which is present in the ulcerated epithelium. This promotes scarring and wound healing.
Indications
N-acetylcysteine eye drops are used for corneal damage, inflammation, ulceration and disease, and dry eye. Corneal affections with increased collagenase activity:
- Ulcer serpens.
- Ulcus corneae in metaherpetic keratopathy.
- Alkali burn of the cornea.
- Keratitis neuroparalytica.
- Keratitis e lagophthalmo.
- Various recurrent, poorly healing erosions with incipient ulceration.
- Corneal affections in which a mucolytic effect is indicated.
- Keratitis filiformis in severe cases of dry-eye syndrome.
Dosage
According to the professional information and the doctor’s instructions. Two drops are usually given into the conjunctival sac 3 to 4 times a day. At the beginning of treatment, the drug may also be administered hourly. Solmucol eye drops (over-the-counter) were stored in the refrigerator after opening and had a shelf life of about two weeks after opening.
Contraindications
- Hypersensitivity
For complete precautions, see the drug label.
Interactions
Interactions are possible with antibiotics and antibiotic eye drops.
Adverse effects
Possible adverse effects include transient burning and irritation and allergic or pseudoallergic reactions.