INTRODUCTION:

Chlorhexidine is a cationic biguanide antiseptic. Chlorhexidine digluconate is first introduced commercially in the United Kingdom as a disinfectant and topical antiseptic.^[1] It demonstrates its ability to inhibit the formation and development of plaque. The antiseptic is the most effective and safest anti-plaque agent to date, and is indicated for use in the general population and in high risk groups of patients.^[2]Chlorhexidine is added to a ventilator bundle with comprehensive oral care.

Uses:

Chlorhexidine is used in disinfectants (disinfection of the skin and hands), cosmetics (additive to creams, toothpaste, deodorants, and antiperspirants), and pharmaceutical products (preservative in eye drops, active substance in wound dressings and antiseptic mouthwashes). ^[3]

1. It is used to kill bacteria that cause infections.

2. It is found in many medicines that are applied directly to the affected area of the body.

3. It is an antiseptic treatment.

4. It is used to treat and prevent infections.

5. Chlorhexidine has also been applied to medical devices such as dental implants, vascular catheters, needleless connectors and antimicrobial dressings. Chlorhexidine, when applied to or impregnated in medical devices kills organisms and protects against microbial colonization and subsequently biofilm development.

Mode of action:

Antibacterial activity:

Chlorhexidine is a broad-spectrum biocide effective against Gram-positive bacteria, Gram-negative bacteria and fungi. The bactericidal effect is a result of the binding of this cationic molecule to negatively charged bacterial cell walls. At low concentrations of chlorhexidine, this results in a bacteriostatic effect, at high concentrations, membrane disruption results in cell death.^[4]Chlorhexidine inactivates microorganisms with a broader spectrum than other antimicrobials (e.g. antibiotics) and has a quicker kill rate than other antimicrobials (e.g. povidone-iodine).^[5] Chlorhexidine kills by disrupting the cell membrane.^[6] Chlorhexidine is a positively-charged molecule that binds to the negatively-charged sites on the cell wall; it destabilizes the cell wall and interferes with osmosis.^[7]

Antifungal activity:

The mechanism of action for fungi is very similar to bacteria. Candida species is the most common of the fungi present in both healthy and medically compromised individuals. ^[8] Fungi have occasionally been found in infected root canals that have not had any previous endodontic treatment.^[9] The fungus uptakes chlorhexidine in a short amount of time and impairs the integrity of the cell wall and the plasma membrane entering the cytoplasm resulting in leakage of cell contents and cell death.^[10]Studies with Candida exposed to chlorhexidine have shown the coagulation of nucleoprotein and alterations of the cell wall allowing the possible escape of cytoplasmic components to the plasmalemma.

Biofilms:

Biofilms are a complex aggregation of microorganisms that occur on organic (e.g. dental plaque) or inorganic surfaces. They are characterized by structural heterogeneity, genetic diversity, complex community interactions, and an extracellular matrix of polymeric substances. This matrix protects the cells within it and increases their resistance to antimicrobials. Many antimicrobial agents have a difficult time eliminating organisms in a biofilm. Chlorhexidine has shown the ability to help inhibit adherence of microorganisms to a surface thereby preventing growth and development of biofilms.

Dental uses:

^1.In oral applications, chlorhexidine binds to the mouth tissue, oral mucosa and teeth. It is then released over time to kill bacteria and fungi. ^[13]This helps to reduce the bacterial count and prevents dental plaque. It has become the gold standard in dentistry due to its ability to adhere to soft and hard tissue and maintain a potent sustained release.^[14]

^2.Rinsing with warm chlorhexidine solution reduced plaque vitality to a significantly greater degree than did cold chlorhexidine at the same concentration.^[15]

3. Wounds are usually protected by a standard periodontal dressing and their rate of healing, when assessed by exudates and bleeding tendency, is quicker when chlorhexidine is included in the dressing. Gingivectomy wounds heal adequately when subjected to chlorhexidine rinse. Chlorhexidine mouth rinse 0.2% has been shown markedly to reduce the bacterial load, which tends to increase during jaw immobilization, and to improve plaque control.

4. Chlorhexidine will help to control plaque accumulation in patients with drug- induced gingival overgrowth, although it has no effect in minimizing the enlargement^.(Russelland Bay 1978)

5. It has been shown that chlorhexidine mouth rinses and chlorhexidine gels reduce the incidence, duration and severity of recurrent minor aphthous ulceration.

6. 2% Chlorhexidine solution when used for root canal irrigation along with conventional root canal irrigation methods increases the success rate of the root canal treatment.

Chlorhexidine products:

· Mouth rises

· Gel

· Sprays

· Toothpaste

· Varnishes

Side effects:

In oral use as a mouth rinse chlorhexidine has been reported to have number of local side effects like

1. Brown discoloration of teeth.

2. Desquamative gingivitis, dysgeusia

3. Oral mucosa erosion

4. Unilateral and bilateral parotid swelling is an extremely rare occurrence

5. Contact dermatitis is a common adverse reaction. (Krautheim et al.2004)

CONCLUSION:

Chlorhexidine has a wide range of activity against both gram positive and gram negative bacteria. It is an effective antifungal agent especially against C.albicans. It is also used as a irrigant in root canal treatment. In rare cases chlorhexidine may cause allergic reactions.

REFERENCES:

1. Puig Silla M, Montiel Company JM, Almerich Silla JM. Use of chlorhexidine varnishes in preventing and treating periodontal disease: a review of the literature. Med Oral Patol Oral Cir Bucal 2008; 13:E257-60

2. Thomas Güthner et al. (2007), "Guanidine and Derivatives", Ullman's Encyclopedia of Industrial Chemistry (7th ed.), Wiley, p. 13

3. Leikin, Jerrold B.; Paloucek, Frank P., eds. (2008), "Chlorhexidine Gluconate", Poisoning and Toxicology Handbook (4th ed.), Informa, pp. 183–184

4. McDonnell, Gerald and A. Denver Russell. "Antiseptics and Disinfectants: Activity, Action and Resistance." Clinical Microbiology Reviews 12.1 (1999): 147-79

5. United States. CDC. Guideline for Prevention of Surgical Site Infection, 1999. By Alicia J. Mangram, Teresa C. Horan, Michele L. Pearson, Leah C. Silver, and William R. Jarvis. CDC, Apr. 1999. Web. 13 Aug. 2012.

6. Puig Silla M, Montiel Company JM, Almerich Silla JM. Use of chlorhexidine varnishes in preventing and treating periodontal disease: a review of the literature. Med Oral Patol Oral Cir Bucal 2008; 13:E257-60. Siqueira and Sen 2004

7. White RR. Hays GL, Janer LR (1997) Residual antimicrobial activity after canal irrigation with chlorhexidine. Journal of Endodontics 229-31

8. McDonnell, Gerald and A. Denver Russell. "Antiseptics and Disinfectants: Activity, Action and Resistance." Clinical Microbiology Reviews 12.1 (1999): 147-79.

9. Bobichon H, Bouchet P. Action of chlorhexidine on budding Candida albicans:screening and transmission electron microscope study. Mycopathologia. 1987; 100: 27-35.

10. Mohammadi,Z. and P.V. Abbott. “The Properties ans Applications of chlorhexidine in Endodontics.” International Endodontic Journal 42.4 (2009): 288-302.

11. Puig Silla M, Montiel Company JM, Almerich Silla JM. Use of chlorhexidine varnishes in preventing and treating periodontal disease: a review of the literature. Med Oral Patol Oral Cir Bucal 2008; 13:E257-60.

12. Mathur, Setu, Tanu Mathur, Rahul Srivastava, and Rohit Khatri. "Chlorhexidine: The Gold Standard in Chemical Plaque Control." National Journal of Physiology, Pharmacy and Pharmacology 1.2 (2011): 45-50. Print.

13. Konig J, Storcks V, Kocher T, Bossmann K, Plagmann HC. Anti-plaque effect of tempered 0.2% chlorhexidine rinse:an in vivo study. J Clin Periodontol 2002;29(3):207-210.

Received on 28.08.2014 Modified on 06.09.2014

Research J. Pharm. and Tech. 7(12): Dec. 2014; Page 1492-1493