Wellington, Sept 21 NZPA - The makers of pain killers have rejected claims their drugs may be linked to a three-fold increase in the "flesh-eating bug" in New Zealand hospitals since 1990.

In 2002, New Zealand doctors were told to be careful when using a common painkiller when treating children with chickenpox -- because of a link to necrotising fasciitis, sometimes referred to as a flesh eating disease.

Ibuprofen, sold under brand-names including Nurofen, is in a group of non-steroidal anti-inflammatory drugs (Nsaids) -- which includes Voltaren -- all of which have been linked to the disease.

Nsaids could increase the risk of the disease by impairing immune response, or by masking of the symptoms of secondary infection, leading to delayed diagnosis and treatment, said Starship children's hospital paediatrician Lesley Voss.

She urged doctors on the Ministry of Health website to be cautious when using ibuprofen in treating chickenpox.

But reports suggesting a link between Nsaids and necrotising fasciitis were incorrect, said the New Zealand Self-Medication Industry (NZSMI), the industry body representing non-prescription consumer healthcare products sector.

There was no scientific evidence for cause and effect link to Nsaids, including ibuprofen, said executive director Tim Roper.

"Nsaids are extremely effective for the relief of pain and inflammation and are used safely by millions of people worldwide.

"As with many medicines, Nsaids are continually monitored and there has been no association between necrotising fasciitis and these products," he said.

The products underwent a rigorous evaluation process before they are made available for use in New Zealand and Medsafe imposed strict labelling requirements to ensure consumers were able to use them correctly, he said.

The rare necrotising fasciitis infection occurs in the deeper layers of skin and is typically caused by many types of bacteria entering an open wound, especially after major surgery.

Patients usually complain of intense pain around the infection and as the disease spreads, skin will change to a violet colour before turning black when it dies.

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