Antiseptic

Author: Vanessa Ngan, Staff Writer, 2005.


What is an antiseptic?

An antiseptic is a chemical agent that slows or stops the growth of micro-organisms (germs) on external surfaces of the body and helps to prevent infections. Antiseptics should be distinguished from antibiotics that destroy micro-organisms inside the body, and from disinfectants, which destroy micro-organisms found on inanimate (non-living) objects. However, antiseptics are often referred to as skin disinfectants.

Most chemical agents can be used as both an antiseptic and a disinfectant. The purpose for which it is used is determined by its concentration. For example hydrogen peroxide 6% solution is used for cleansing wounds, while stronger solutions (> 30%) are used in industry as a bleach and oxidising agent.

Antiseptics

Types of antiseptic

Antiseptics can be classified according to their chemical structure. Commonly used antiseptic groups include alcohols, quaternary ammonium compounds, chlorhexidine and other diguanides, antibacterial dyes, chlorine and hypochlorites, inorganic iodine compounds, metals, peroxides and permanganates, halogenated phenol derivatives and quinolone derivatives. The following table lists some of the agents within these groups.

Alcohol

  • Ethyl alcohol 70% 
  • Isopropyl alcohol 70%
  • Used as skin disinfectant

Quaternary ammonium compound

  • Benzalkonium chloride 
  • Cetrimide 
  • Methylbenzethonium chloride 
  • Benzethonium chloride 
  • Cetalkonium chloride 
  • Cetylpyridinium chloride 
  • Dofanium chloride 
  • Domiphen bromide
  • Used as skin disinfectant, irrigation, and to preserve eye drops

Chlorhexidine and other diguanide

  • Chlorhexidine gluconate 
  • Chlorhexidine acetate
  • Used as pre-operative skin disinfectant, to treat wounds, and for bladder irrigation

Antibacterial dye

  • Proflavine hemisulphate 
  • Triphenylmethane 
  • Brilliant green 
  • Crystal violet 
  • Gentian violet
  • Used as skin disinfectant and to treat wound or burn

Peroxide and permanganate

Halogenated phenol derivative

  • Chlorocresol 
  • Chloroxylenol 
  • Chlorophene 
  • Hexachlorophane/hexachlorphene (no longer available)
  • Triclosan
  • Used as skin disinfectant and in medicated soap and solution

Quinolone derivative

  • Hydroxyquinoline sulphate 
  • Potassium hydroxyquinoline sulphate 
  • Chlorquinaldol 
  • Dequalinium chloride 
  • Di-iodohydroxyquinoline
  • Used to treat wounds, in throat lozenges and as a skin disinfectant

Miscellaneous

  • Burow's solution (aqueous solution of aluminium acetate) 
  • Bleach baths

Uses of antiseptic

Antiseptic is mainly used to reduce levels of microorganisms on the skin and mucous membranes. The skin and mucous membranes of the mouth, nose, and vagina are home to a large number of micro-organisms (which are normally harmless).

  • When the skin or mucous membranes are damaged or breached in surgery, antiseptic is used to disinfect the area and reduce the chances of infection.
  • People who are treating patients with wounds or burns should wash their hands with antiseptic solution to minimise the risk of cross infection.

Antiseptics are used for:

  • Handwashing – chlorhexidine gluconate and povidone iodine solutions are often used in hand scrubs and hand rubs in hospital settings.
  • Pre-operative skin disinfection – antiseptics applied to the operation site to reduce the resident skin flora. Caution should be used in facial use of solutions containing chlorhexidine, as these can injure the eye causing keratitis.
  • Mucous membrane disinfection – antiseptic irrigations may be instilled into the bladder, urethra or vagina to treat infections or cleanse the cavity prior to catheterisation.
  • Preventing and treating infected wounds and burns – antiseptic preparations are available over-the-counter from your pharmacist to treat minor cuts, abrasions and burns.
  • Treating mouth and throat infections – dequalinium chloride has both antibacterial and antifungal properties and is the active ingredient in antiseptic throat lozenges.

Precautions when using antiseptic

Strong antiseptic should be diluted before it is applied to the skin, as concentrated products including chlorhexidine may cause chemical burns or severe irritant contact dermatitis. Prolonged contact with diluted antiseptic can also cause erosive contact dermatitis, as described with chlorhexidine-impregnated dressings.

Antiseptic bought from the pharmacy should not be used for more than one week. Stop using the antiseptic and see a doctor if:

  • The affected area has not healed or improved.
  • There is a large wound, deep cut, large burn, or abrasion imbedded with particles that won’t wash away
  • Injury is due to human bite or animal bite 
  • An eye is injured. 

Do not use antiseptics to treat sunburn or deep skin infection. Remember that antiseptic only reduces microorganisms on the surface of the tissue and that antibiotics will be needed to treat infection within the tissues.

People with allergies of any kind should check with a doctor or pharmacist before using an over-the-counter antiseptic product. Some antiseptics can irritate the skin and cause allergic contact dermatitis. Chlorhexidine has been reported to rarely cause anaphylaxis.

What about antibacterial soap?

In September 2016, the US Food & Drug Administration (FDA) issued a final rule establishing that over-the-counter (OTC) consumer antiseptic wash products containing certain active ingredients can no longer be marketed. Nineteen of these are listed, including triclosan and triclocarban. Regulators in other countries may follow with similar rulings. Reasons include:

  • There is no scientific evidence that antibacterial wash is any better than soap and water in preventing the spread of germs
  • Household use of antibacterial ingredients may do more harm than good over the long-term, such as promoting bacterial resistance (see MRSA)

Hand sanitiser containing at least 60% alcohol can be used, if soap and water are not available.

New Zealand approved datasheets are the official source of information for these prescription medicines, including approved uses and risk information. Check the individual New Zealand datasheet on the Medsafe website.

 

Related Information

References

On DermNet NZ

Other websites

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