The T-value in the score for hazard refers to chronic toxicity. Underlying data for P, B and T are from Fass. Risk see the report Goodpoint 2019.
The major metabolite – desloratadine (DL) – is pharmacologically active and is responsible for much of the clinical effect.
Fass environmental information for Clarityn (loratadine) from Bayer (downloaded 2019-11-28).
Persistence: "The biotic degradation half-life of 217 to 301 days justifies the phrase: Loratadine is potentially persistent, in accordance with the half-life criterion developed for the aquatic-sediment study OECD 308."
Bioaccumulation: "Log POW 2.38 (pH 5), 2.33 (pH 7), 2.0 (pH 9) (FDA TAD 3.02). Loratadine has a low potential for bioaccumulation."
Chronic toxicity: There are data for 3 trophic levels, most sensitive algae (Pseudokirchneriella subcapitata) NOEC 53 microg/L.
PEC/PNEC is based on sales data in Sweden in year 2017. PEC/PNEC = 0.016 which gives the risk insignificant.
Report Pharmaceutial residues in the Stockholm aquatic environment. Loratadine has been found in purified wastewater up to 3.7 ng/L and in sludge up to 0.014 mg/kg DM (dry mass).
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