Underlying information för B is from Fass. For the risk, see the report Goodpoint 2019.
Fass environmental information for Tavegyl (clemastine) from GlaxoSmithKline Consumer Healthcare (downloaded 2019-11-27).
Persistence: No data.
Bioaccumulation: "Log Pow is 6.4 calculated using a Novartis in-house program."
Toxicity: No data.
Risk of environmental impact of clemastine cannot be excluded, since no ecotoxicity data are available.
Clemastine has been found in purified wastewater within Region Stockholm during 2012–2016 but was not detected in measurements 2017 and 2018.
Comparative assessment of environmental risk when using the antihistamines desloratadine, cetirizine, loratadine, ebastine, clemastine and fexofenadine from a Swedish perspective (Report Goodpoint 2019).
Summary assessment based on (expected) water exposure in relation to toxicity and interaction with targets. Use of clemastine (Tavegyl) is considered to pose a risk of impact on aquatic organisms. It is supported by the fact that measured concentrations in the environment are in good agreement with predicted levels, these levels, although very low, are considered to be able to accumulate in fish to therapeutic concentrations given its high fat solubility (for which there is a reasonable consensus assessment), and finally have levels above Cmax been detected in wild fish. Studies on effects on aquatic organisms are lacking for clemastine, so the assessment is based entirely on the above. Thus, what kind of pharmacological effect can be expected from clemastine through its effect on the histamine receptors, and how severe these are, has not been investigated. The risk of impact is significantly lower, but not negligible, for fexofenadine. The other studied antihistamines pose a low risk based on expected exposure and the likelihood of accumulation in biota to near therapeutic concentrations, at the same time the assessment is uncertain due to insufficient efficacy data. An exchange of clemastine with one of the other studied antihistamines is recommended from an environmental point of view.
Author: Health and Medical Care Administration, Region Stockholm