The T-value in the score for hazard refers to acute toxicity. Underlying data for P, B and T are from Fass.se, see below.
Concentrations of trimethoprim in Swedish wastewater treatment plants is likely to select for bacterial resistance.
Trimethoprim is included in the Stockholm County Council's table of pharmaceuticals with risk for negative environmental impact according to the environmental program, 2017–2021. Trimethoprim has been detected in treated wastewater, surface water and fish in Stockholm County in the last five years (2012–2016).
Studies have shown that even low concentrations of antibiotics in the environment may trigger antibiotic resistance and therefore measures should be taken to ensure that as little as possible ends up in our environment.
Is recommended in The Wise list. Environmental classification of pharmaceuticals is taken into consideration, sometimes with other environmental aspects, when selecting pharmaceuticals for the Wise list. When comparable pharmaceuticals are equivalent to medical effects, safety and pharmaceutical efficacy, environmental impact and price are considered.
Fass environmental information for Bactrim (sulfamethoxazole, trimethoprim) (downloaded 2013-07-03).
Persistence: "Based on several measurements, half-lives in the aquatic compartment are estimated at 20–100 (geometrical average ~45) days, >42 days and 5.7 days in a microcosm study, which qualifies Trimethoprim as nonpersistent to persistent."
Bioaccumulation: Log D of 0.76 at pH 7.
Acute toxicity: There are data for 3 trophic levels, lowest for algae (Rhodomonas salina, Cryptophyceae) 16 000 microg/L.
PEC/PNEC is based on sales data in Sweden in year 2009. PEC/PNEC = 0.008 which gives the risk insignificant, i.e. consideration has not been given to measured levels in the environment..
No recent environmental information on Fass.se has been found (2018-09-10). It is voluntary for manufacturers to provide information about environmental impact on fass.se.
Concrete proposals on how to work to reduce emissions of environmentally harmful pharmaceuticals on the list have been developed in close cooperation with the Stockholm Drug and Therapeutics Committee's expert advice. The action proposals were developed from an environmental perspective. The patient's best always goes first and several pharmaceuticals on the list are also included in the Wise list. However, for such pharmaceuticals, there may be measures that could reduce the environmental impact.
Concrete proposal for trimethoprim
Comparative assessment of environmental risk and risk of resistance selection in the environment using trimethoprim and pivmecillinam in Sweden.
From a resistance-selection-risk perspective in wastewater treatment plants, pivmecillinam appears to be a slightly better alternative than trimethoprim.
Author: Health and Medical Care Administration, Region Stockholm