Monograph: |
Chymotrypsin
Indications: Surgery, ophthalmic, adjunct
DESCRIPTION:
Chymotrypsin is a lyophilized form of crystalline chymotrypsin, a proteolytic enzyme obtained from the pancreas of the ox. The diluent is a sterile balanced salt solution to be used for reconstituting crystals. Package includes one vial chymotrypsin, 750 U.S.P. Units; and one 9 mL vial of diluent containing: Sodium Chloride 0.49%, Sodium Acetate 0.39%, Sodium
Citrate 0.17%, Potassium Chloride 0.075%, Calcium
Chloride 0.048%, Magnesium Chloride 0.03%,
Hydrochloric Acid and/or Sodium Hydroxide (to adjust pH), Water for Injection.
CLINICAL PHARMACOLOGY:
When instilled into the posterior chamber of the eye, its enzymatic action causes dissolution of zonular fibers attached to the lens.
INDICATIONS AND USAGE:
For enzymatic zonulysis in intracapsular lens extraction.
CONTRAINDICATIONS:
Contraindicated in significant anterior displacement of the lens iris diaphragm with impending vitreous loss or other conditions in which loss of vitreous is a significant problem (e.g., intracapsular extraction of congenital cataracts); and in those persons who have shown hypersensitivity to any component of this preparation.
WARNINGS:
Do not use the reconstituted solution if cloudy or if it contains a precipitate. Do not autoclave the powder or the reconstituted solution-excessive heat, alcohol, and other chemicals used for sterilization inactivate the enzyme. After the operation, discard any unused portion including the diluent. The solution contains no preservative and should not be used for more than one patient.
PRECAUTIONS:
Chymotrypsin may produce an acute rise in intraocular pressure following surgery. This is especially true in patients with poor facility of outflow.
Use of Chymotrypsin is not advised in patients under 20 years of age. Ensure that the synechiae are separated, since this enzyme will not lyse them.
ADVERSE REACTIONS:
Increases in intraocular pressure, moderate uveitis, corneal edema, and striation have been reported.
DOSAGE AND ADMINISTRATION:
Reconstitute immediately prior to the start of surgery. Utilize aseptic technique when inserting a syringe into the rubber stopper of the diluent bottle. It is recommended that the Chymotrypsin be reconstituted with 5mL of the diluent to provide the dilution of 150 units of chymotrypsin per mL which is comparable to a 1:5,000 dilution.
Following cataract section, irrigate the posterior chamber with the reconstituted Chymotrypsin using 0.25 to 0.5 mL (evenly distribute around circumference of the lens). Wait two to four minutes from time of irrigation with Chymotrypsin then irrigate the anterior chamber and the corneal wound edges with at least 2mL of the diluent or balanced salt solution.
NOTE: If zonules are still intact, irrigate with additional Chymotrypsin and wait an additional two minutes before flushing with diluent.
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