When pharmaceuticals are consumed by patients, there may be some active ingredient that is not completely metabolised (biochemically altered and inactivated). The patient excretes the portion that is not metabolised. These small quantities of material are then transported to wastewater treatment systems where most of them are removed but some are discharged to receiving streams.

Historically, the presence of pharmaceuticals in environmental media has been estimated. Recently, as a result of advances in analytical techniques, pharmaceuticals can be measured in wastewater, surface water (rivers and streams) and drinking water.

Pharmaceuticals in the environment have been regulated in the USA since 1977 with the US Food and Drug Administration (FDA) taking responsibility under the auspices of the National Environmental Policy act of 1969. Regulation occurs through the environmental review process for New Drug Applications submitted to the FDA. In the late 1980s additional information was required from pharmaceutical companies by the FDA and more extensive information was provided in environmental risk assessments that accompanied New Drug Applications. An evaluation of the data submitted from the late 1980s through the mid-1990s led the FDA to revise the regulations in 1997 to minimise environmental risk assessment data required in New Drug Applications.

This issue has also received regulatory attention in Europe through the submission of Environmental Risk Assessments to accompany Marketing Authorisation Approval. In Canada, a requirement for environmental assessment is under consideration.

GSK has been actively involved in industry efforts to develop improved environmental risk assessment models. These models can then be used to identify potential risks of GSK pharmaceutical products entering the environment through patient use. Assessments using these models and currently available human and environmental effects data indicate that GSK pharmaceuticals in the environment do not present a risk to humans or the environment. As part of its product stewardship activities, GSK continues to monitor the latest scientific studies and findings to continually improve risk assessments in this area.