Surface water

Until now, little has been known about what types of psychotropic drugs are present in Dutch surface water. To gain more insight, the scientists combined data from the Water Quality Portal with data from the Medicines and Medical Aids Information Project run by the National Health Care Institute. The water authorities do not take measurements for all psychopharmaceuticals, and the effect the aquatic environment is not known for all medicines. To identify the main sources of psychotropic drugs in the surface water, the researchers used detailed data from a water treatment plant in the village of Winterswijk in the east of the Netherlands.

‘Our measurements show that substances such as carbamazepine, oxazepam and fluoxetine are regularly found in surface water,’ says researcher Caroline Moermond of RIVM. ‘The main source is the use by patients at home. Sewage treatment plants are only able to remove a part. As a result, in some places, carbamazepine and oxazepam pose a risk to aquatic organisms such as fish and small crustaceans. Psychotropic drugs influence the behaviour of these organisms, making them more aggressive or more passive. This can ultimately have an effect on multiple food chains.’

Psychopharmaceuticals

The prescription of antidepressants, antipsychotics, sleeping pills, tranquilizers and other psychotropic drugs is on the increase worldwide. Oxazepam, the drug found to appear frequently in Dutch surface water, has been one of the most commonly prescribed medicines in the Netherlands for many years. It helps to reduce feelings of anxiety and tension, but is also widely used to treat symptoms of stress or burnout. Carbamazepine is a drug that suppresses the symptoms of epilepsy and is also regularly prescribed for the treatment of patients with bipolar disorder.

UM researcher and psychiatrist Jurjen Luykx says that doctors should be much more alert to the amount of medicines they prescribe. ‘The way we prescribe medication also deserves attention. This includes the question of whether and how quickly we can start lowering the dose. We also need to provide more advice to patients on how best to deal with leftover medication, to prevent it from being flushed down the toilet. What’s more, on the basis of the results of this study, we can investigate cases in which other drugs that are as effective as oxazepam and carbamazepine could be given priority in treatment guidelines. It would be good if the guidelines took more account of the impact of treatments on the environment and climate in the future.’