Bilastine: an environmental risk assessment

Bilastine is a new oral selective, non-sedating histamine H1 antagonist for the symptomatic treatment of allergic rhinoconjunctivitis and urticaria. The European Medicines Agency requires an Environmental Risk Assessment (ERA) for all novel medicines for human use.

To calculate the bilastine predicted environmental concentration in surface water (PECsw; phase I ERA), and to determine the effects of bilastine on aquatic systems (phase II [tier A]).

Bilastine PECsw was calculated using the maximum daily dosage (20 mg), assuming that all administered bilastine was released into the aquatic environment. A persistence, bioaccumulation and toxicity assessment was conducted using the log Kow from the molecular structure. In phase II (tier A), a ready biodegradability test was performed, and bilastine's potential toxicity to various aquatic and sediment-dwelling micro-organisms was evaluated.

Bilastine PECSW was calculated as 0.1 μg L(-1), and the compound was not readily biodegradable. Bilastine had no significant effects on Chironomus riparius midges, or on the respiration rate of activated sludge. For green algae, the bilastine no observed effect concentration (NOEC) was 22 mg L(-1); bilastine had no effect on zebra fish development, or on the reproduction rate of daphnids.

Bilastine NOEC values against zebra fish, algae, daphnids, and aerobic organisms in activated sludge were at least 130 000-fold greater than the calculated PECSW value.

No environmental concerns exist from bilastine use in patients with allergic rhinoconjunctivitis or urticaria.