SMTL Dressings Datacard

Product Name: Metrotop
Classification Name: Dressing Metronidazole Gel
Manufacturer: Pharmacia and Upjohn Ltd


Metrotop is a colourless, transparent, hypromellose gel, containing 0.8%w/v Metronidazole BP and Benzalkonium Chloride Solution BP 0.02%v/v. The gel is used alone or as an adjunct to systemic therapy to combat infection in malodorous wounds. Although traditionally associated with the management of anaerobic infections, laboratory studies have shown that at the concentration used in Metrotop, metronidazole is also active against a range of aerobic bacteria. It is likely therefore, that the gel may be of value in combating odour caused by these organisms also. The moist environment produced by the gel may also help to promote wound debridement by facilitating autolysis of slough and necrotic tissue.


Metrotop has a product licence for use as a de-odouriser in the management of malodorous fungating tumours but it has also been used successfully in the treatment of other types of malodorous wounds such as pressure areas and leg ulcers, found on microbiological investigation to be clinically infected with organisms sensitive to metronidazole. However, the widespread and indiscriminate use of Metrotop for these applications is not recommended.


Metrotop should not be applied to individuals who are hypersensitive to metronidazole.

Method of use

Metrotop should be applied liberally to the surface of a previously cleansed wound and covered with a suitable secondary dressing, the choice of which will be governed by the nature of the wound. A simple absorbent pad will be adequate for heavily exuding wounds but for drier wounds the use of a more occlusive product is recommended to retain moisture and prevent both the wound and gel from drying out. A perforated plastic film dressing such as Melolin or Telfa may be suitable for this purpose.

Small cavity wounds may be partially filled with Metrotop, larger cavities may be lightly packed with ribbon gauze impregnated with the gel.

Frequency of Change

Metrotop is generally applied once or twice a day depending upon the location and condition of the wound.


The use of systemic metronidazole may produce a number of undesirable effects and although there is no evidence that significant amounts of the drug are absorbed following topical application, potential users should consult the literature for further information if large quantities of gel are to be applied over extended periods.

Because there is a theoretical possibility that metronidazole may be absorbed following topical application of Metrotop, the manufacturers recommend that the gel is not used during pregnancy or lactation unless considered essential by the medical officer in charge.


Metrotop is supplied in plastic tubes.


15 g tubes in boxes of 12

30 g tube

Legal Category

Prescription Only Medicine [POM]


1. Ashford R, et al., Double blind trial of metronidazole in malodorous ulcerating tumours, Lancet 1984, i, 874-5.

2. Jones PH, et al., Treatment of anaerobically infected pressure sores with topical metronidazole, Lancet, 1978, i, 214.

3. Thomas S, et al., The antimicrobial properties of two metronidazole medicated dressings used to treat malodorous wounds, Pharm. J., 1991, 246, 264-266.

4. Thomas S, Current practices in the management of fungating lesions and radiation damaged skin, Surgical Materials Testing Laboratory, Bridgend 1992,

5. Bower M, et al., A double-blind study of the efficacy of metronidazole gel in the treatment of malodorous fungating tumours, Eur. J. Cancer, 1992, 28a, 888-889

Revision Details

Revision AuthorDr S. Thomas
Revision No 1.4
Revision date1997/12/16

This datacard has been prepared from data provided by the manufacturer and/or from published literature.

All materials copyright © 1992-2007 by the Surgical Materials Testing Lab. unless otherwise stated.

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Last Modified: Thursday, 28-Mar-2002 10:22:39 GMT