The T-value in the score for hazard refers to chronic toxicity. Underlying data for P and T are from Fass.se, see below. Data for B is from the report Relative assessment of environmental risk when using angiotensin II antagonists irbesartan and losartan (Goodpoint 2018), see below.
Measured concentrations of irbesartan in surface water are estimated to accumulate in fish at therapeutic concentrations. However, measured concentrations found in single fish have been lower. Mechanism-based data is missing.
Irbesartan is included in the Stockholm County Council's table of pharmaceuticals with risk for negative environmental impact according to the environmental program 2017–2021. Irbesartan has been detected in treated wastewater and surface water in Stockholm County in the last five years (2012–2016).
Fass environmental information for Approvel (irbesartan) (downloaded 2018-07-09).
Persistence: "As DT50total system < 32 days with still more than 15% of the parent compounds remaining at the end of the study, the correct phrase is: “Irbesartan is slowly degraded in the environment”."
Bioaccumulation: Log Kow = 1.13 at pH 7 (OECD 107).
Chronic toxicityt: There is NOEC for 3 trophic levels, lowest NOEC for fish (Pimephales promelas) ("NOEC 28 days (growth)") 7 040 microg/L.
PEC/PNEC is based on sales data in Sweden in year 2016. PEC/PNEC = 0.000387 which gives the risk insignificant, i.e. consideration has not been given to measured levels in the environment.
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 irbesartan
Relative assessment of environmental risk when using angiotensin II antagonists irbesartan and losartan in Sweden (Report Goodpoint 2018)
Measurements of irbesartan in incoming and outgoing wastewater in three wastewater treatment plants in Stockholm since 2012 in SLL's internal measurement series, show levels of up to 373 ng/L and, in principle, irbesartan is not reduced in the wastewater treatment plants. Irbesartan is also not microbially readily degradable in laboratory studies.
According to Fass (Aprovel, Sanofi), irbesartan has a log P of 1.13 but Drugbank reports significantly higher predicted log P between 4.5 and 5.56. The fact that irbesartan is found in wild Swedish fish speaks strongly against a log P of 1.13.
Losartan, recommended in the Wise list, is better from an environmental point of view than irbesartan.
Author: The Pharmaceutical unit of Region Stockholm