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   Environmentally harmful drug product with a poor risk-benefit profile

Diclofenac belongs to the group of non-steroidal anti-inflammatory drugs. It contains an active pharmaceutical ingredient with anti-inflammatory, analgesic and antipyretic properties, and is available as a gel, injections, tablets or drops. The gel with the active ingredient diclofenac is one of the most commonly used painkillers in orthopaedics in Germany and is advertised worldwide. Applied to the skin at the site of pain, it has been proven to work with only minor systemic side effects. In dermatology, diclofenac is used to treat superficial skin tumours, so-called actinic keratoses, which can occur due to lifelong UV irradiation. The incidence is increasing. Diclofenac can be purchased over the counter in most countries and is relatively safe to use. In Germany, the total consumption of diclofenac is about 85 tonnes per year.

Diclofenac is harmful to animal life


Diclofenac is toxic to the kidneys of birds. In India and Pakistan, three native vulture species have been almost completely extirpated since the 1990s after ingesting diclofenac in the meat of dead cattle that had been treated for rheumatism. In fish, the liver, kidneys and gills are damaged by the introduction of diclofenac through sewage. To make matters worse, some species of psyllids convert diclofenac into diclofenac methyl ester, which is poorly soluble in water, is excreted less efficiently and therefore accumulates in living organisms. In addition, degradation in water bodies is hindered by chemical compounds such as carbonates and phosphates from detergents, which are found in large quantities in wastewater. Unlike ibuprofen, for example, diclofenac cannot be filtered out of the wastewater by sewage treatment plants with the possibilities that have existed up to now. The problem also affects other drugs such as neuroleptics or antibiotics, so that a 4th clarification stage is to be introduced in future.

The risk-benefit profile of diclofenac is questionable

Regardless of the need for a technical solution to the wastewater issue, the question of the usefulness of the application as well as the risk-benefit profile of diclofenac topicals must be raised.

Physicians and therapists should critically question their recommendation and prescription of topically applied diclofenac and consider alternatives if necessary. In particular, the following considerations should be borne in mind:

  • Diclofenac gel is poorly absorbed through the skin and 94-99% of the product goes directly into the waste water after the first wash at the latest,

  • The efficacy of the pain-relieving gel for joint diseases other than osteoarthritis of the knee joint and rheumatic inflammation of the finger joints has not been proven,

  • There are herbal or, if not otherwise possible, ibuprofen-based alternatives.

Last but not least, it is important to consider whether medicines such as diclofenac or even other ingredients such as triclosan should not be reserved strictly for medically prescribed indications, instead of finding worldwide distribution and being heavily advertised in conventional products and over-the-counter medicines on the market.

Water in adequate and clean quantities will become the problem of the future in a world that will be marked by global warming due to the climate crisis. Our health directly depends on the availability of drinking water and usable water for food production. The climate crisis threatens our health as the greatest therapeutic challenge of the 21st century. However, humans are responsible for conserving the earth's resources. Working sustainably therefore does not only mean economically and according to the indication, but above all includes informing patients about the ecological consequences of their therapy and possible alternatives.

© Dr. med. Gudula Keller, Orthopaedist, and Dr. med. Susanne Saha, Dermatologist, 07/2021

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