Increasing interest of society in natural products, disappointing and dissatisfying results of conventional therapy, as well as the “One Health” concept encouraged by authorities are only some of the causes of enhanced significance of phytotherapy in animals. Despite the long and well documented tradition of herbalism veterinary medicine, some pharmacological and toxicological aspects must be carefully analyzed while considering the application of a plant-derived product into treatment protocol.
In contrast to human medicine, veterinary medicine consists of various species with distinct differences in anatomy and physiology. Consequently, safe and efficient phytotherapy is a challenge for many veterinarians. Significant inter-species differences are reflected in diverse pharmacokinetics of phytomedicines. The complexity of gastrointestinal tract, various intensity of gut microorganisms’ activity and the activity of enzymatic systems, predominantly CYP450, are responsible for variable bioavailability of phytocompounds in animals of different species. In cats, special attention must be paid to drugs requiring conjugation with active glucuronic acid since these animals are unable to perform this reaction. Similarly, urine excretion is species-dependent due to various urine pH which may either facilitate or decrease elimination of plant-origin substances and their metabolites. Another animal specific aspect of veterinary phytotherapy includes doping issue. Some herbal constituents are not allowed in sport animals, some other may increase the concentration of concurrently applied drugs and cause a positive result of anti-doping testing. Herb–drug and herb-nutrients interactions, as well as unconscious use of counterfeit phytomedicines are other matters to discuss. Altogether, only rational phytotherapy guarantees the safety and effectiveness people expect.
