Alcaine

Uses

Higher concentrations of Benzalkonium chloride is used as an antiseptic and disinfectant. This is also widely used as a preservative in eye-drops.

Proparacaine is used for procedures in which a topical ophthalmic anesthetic is used for: corneal anesthesia of short duration, e.g. tonometry, gonioscopy, removal of corneal foreign bodies, and for short corneal and conjunctival procedures. It is also used for use prior to surgical operations such as cataract extraction.

Alcaine is also used to associated treatment for these conditions: Diaper Dermatitis, Dry Eye Syndrome (DES), Eye and eyelid infections, Gingivitis, Hemorrhoids, Infantile Eczema, Mouth irritation, Pruritus Ani, Tonsillitis, Throat inflammation, Antisepsis, Disinfection therapy, Eye disinfection, Eye lubrication, Hand Hygiene, Skin disinfection, Wound treatmentLocal anesthesia therapy

How Alcaine works

Although not entirely elucidated, the bactericidal action of benzalkonium chloride is believed to be due to the disruption of intermolecular interactions. Such disruption can cause the dissociation of cellular membrane lipid bilayers of bacteria, resulting in compromised cellular permeability control and the leakage of important cellular contents. Additionally, other important molecular complexes like enzymes which control the maintenance of a great range of respiratory and metabolic cellular activities, are also susceptible to such deactivation. Consequently, a variety of critical intermolecular interactions and tertiary structures in very highly specific biochemical systems that allow bacterial agents to function normally can be readily disrupted or deactivated by cationic surfactants like benzalkonium chloride. .

The exact mechanism whereby proparacaine and other local anesthetics influence the permeability of the cell membrane is unknown; however, several studies indicate that local anesthetics may limit sodium ion permeability through the lipid layer of the nerve cell membrane. Proparacaine may alter epithelial sodium channels through interaction with channel protein residues. This limitation prevents the fundamental change necessary for the generation of the action potential.

Dosage

Alcaine dosage

• Tincture of benzalkonium chloride 1:750 is used for the preoperative disinfection of unbroken skin or treatment of superficial injuries.
• For preoperative disinfection of mucous membranes and denuded skin, benzalkonium chloride solution in concentrations of 1:10000 to 1:2000 is used.
• For irrigation of the eye, a solution of 1:10000 to 1:5000 is used.
• For urinary bladder and urethral irrigation, a solution 1:5000 to 1:20000 is used.
• For vaginal douche and irrigation, benzalkonium chloride solution 1:5000 to 1:20000.

Deep anesthesia as in cataract extraction: Instill 1 drop to the eye every 5 to 10 minutes for 5 to 7 doses.

Removal of sutures: Instill 1 or 2 drops to the eye 2 or 3 minutes before removal of stitches.

Removal of foreign bodies: Instill 1 or 2 drops to the eye prior to operating.

Tonometry: Instill 1 or 2 drops to the eye immediately before measurement.

Side Effects

Repeated application may cause hypersensitivity reactions. May cause nausea and vomiting if ingested.

Occasional temporary stinging, burning and conjunctival redness may occur with the use of Proparacaine.

Toxicity

An oral dose of 100-400 mg/kg or a parenteral dose of 5-15 mg/kg is believed to be fatal in humans .

A potential concern for larger concentrations of benzalkonium chloride to possibly cause corneal damage when implemented as an excipient ingredient in aqueous eye products is an issue that should be discussed between potential patents and their health care providers . Since decreased regular blinking and tear generation in patients experiencing dry eyes due to any number of eye conditions can result in reduced dilution of applied eye drops containing the benzalkonium chloride preservative , alternative options including benzalkonium chloride-free products should be considered.

Additionally, benzalkonium chloride has been reported to cause punctate keratopathy and/or toxic ulcerative keratopathy. In addition, benzalkonium chloride may cause eye irritation and is known to discolour soft contact lenses . There may also be the possibility of benzalkonium chloride containing eye drops to cause some stinging and pain .

There is the possibility of ototoxicity occurring when benzalkonium chloride containing ear drops are applied to the ear .

Benzalkonium chloride used as a preservative in nebulised solutions of anti-asthma drugs has been reported to cause dose-related bronchoconstriction especially in asthmatic patients and has been associated with the precipitation of respiratory arrest .

Despite the fairly widespread cutaneous use of benzalkonium chloride, only limited human evidence of sensitization in relatively small populations of individuals have been reported . Nevertheless, the main adverse effect for topical formulations of benzalkonium chloride is usually the warning 'may cause local irritation' .

Precaution

Prolonged use of a topical ocular anesthetic is not recommended. It may produce permanent corneal opacification with accompanying visual loss.

Interaction

Disinfectants containing quaternary ammonium salts should not be used for skin preparation before injections of viscoelastic solutions. Hyaluronic acid will precipitate in the presence of these salts.

Volume of Distribution

When applied as a topical antibacterial, antiseptic, disinfectant, or sanitizer it is believed that molecules of benzalkonium chloride are poorly absorbed (perhaps due to their large, positively charged nature ), especially considering expectations for such topical applications to keep their biocidal agents available for action at the topical level and to not be absorbed significantly beyond it.

When benzalkonium chloride is implemented as an excipient preservative ingredient in various eye, nose, and ear aqueous products, such products will always have other active pharmacological agents whose volume of distribution will be of greater importance. In these cases the excipients will only ever be present at the minimal levels necessary to maintain the integrity of the product substance.

Moreover, Benzalkonium chloride is currently listed as a Category III ingredient by the United States Food and Drug Administration . Ingredients are listed in the FDA Category III when the data available about them are insufficient to classify as safe and effective, requiring further testing to determine more formal details about elements like human pharmacokinetic studies, and studies on the ingredients' absorption, distribution, metabolism, and excretion.

Elimination Route

Percutaneous absorption is considered to be insignificant .

In one study, benzalkonium chloride absorption was evaluated in women using tampons containing the agent. Venous blood samples were drawn 15 minutes before the tampon application and then again at 15 min, 1 h, 3 h, and 24 h after application. Benzalkonium chloride was not detected in any of the blood samples at any time tested.

Similarly, in another study, benzalkonium chloride absorption was tested in women using tampons containing the agent. Venous blood and breast milk samples were taken 15 minutes before application and 3 h and 24 h after tampon administration. Benzalkonium chloride was not found in any of the subjects' samples. .

Moreover, in a study where benzalkonium chloride solution was placed on the corneal surface of rabbit subjects, at various intervals after administration, the rabbits' eyes would be washed with 1 mL saline and the following tissues and fluids were removed: bulbar and palpebral conjunctiva, aqueous humour, corneal epithelium, endothelium and stroma, iris-ciliary body, lens, vitreous, retina, and choroid. Plasma samples were obtained with direct cardiac punctures. After administration of one drop, benzalkonium chloride was found in the corneal epithelium, endothelium, and stroma, and in the bulbar and palpebral conjunctivae. Benzalkonium chloride loss from ocular tissues was such that about one-third to two thirds of its concentration (depending on the tissue) at 30 min remained after 24 hr; measurable values existed for as long as 120 hr. The administration of multiple drops led to continued accumulation of benzalkonium chloride. .

Elimination Route

Administered benzalkonium chloride is likely eliminated largely in faeces, similar to other quaternary ammonium compounds .

Pregnancy & Breastfeeding use

Use in pregnancy: It is not known whether Proparacaine can cause fetal harm when administered to a pregnant woman or can affect reproduction capacity. Proparacaine should be administered to a pregnant woman only if clearly needed.

Use in lactation: It is not known whether this drug is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when Proparacaine is administered to a nursing mother.

Contraindication

Incompatible with soaps and other anionic surfactants, citrates, iodides, nitrates, permanganates, salicylates, silver salts, tartrates, and zinc oxide and sulfate.

Proparacaine eye drops should be considered contraindicated in patients with known hypersensitivity to any of the ingredients of Proparacaine Hydrochloride.

Special Warning

Pediatric Use: Safety and effectiveness of Proparacaine ophthalmic solution in pediatric patients have been established. Use of Proparacaine is supported by evidence from adequate and well-controlled studies in adults and children over the age of twelve, and safety information in neonates and other pediatric patients.

Geriatric Use: No overall clinical differences in safety or effectiveness have been observed between the elderly and other adult patients.

Storage Condition

Keep below 30°C temperature, away from light & moisture. Keep out of the reach of children.

Store bottles under refrigeration at 2° to 8° C & protect from light. It is desirable that the contents should not be used more than 4 weeks after first opening of the bottle. If solution shows more than a faint yellow color, it should not be used. Keep bottle tightly closed.

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