**1. Introduction**

Giardiasis is a parasitic disease, caused by a protozoan called *Giardia duodenalis*, which shares similar morphological characteristics with other species such as *G. lamblia* and *G. intestinal*, for which the same pathogen has been considered [1–3]; this protozoan affects many domestic and wild species [2]. In the canine and feline species, it is described as *G. intestinalis* [1, 2], previously described as *Giardia canis*; this protozoan affects not only animals but also man [4].

Epidemiology has been considered a cosmopolitan parasite, which causes malabsorption syndrome in the host, causing gastroenteritis in these patients [1, 4], due to the presence of giardia in intestinal mucosa, producing ulcerative lesions and hemorrhagic, it should be made clear that, not being an agent considered cosmopolitan, it does not affect the species of cattle such

as cattle, goats, sheep, and swine [1, 2, 4], it is a seriously pathogenic agent for animal species, that if it causes injuries that produce a consuming disease, considered as a zoonotic disease of global importance [2].

The prevalence is higher in areas with unhealthy conditions [3, 5], where the presence of excreta in the water, excreta management, overcrowding, and warm conditions has been described, favoring the presence of an agent [6]. Transmission is oro-fecal; humans, canines, and felines ingest the infecting cysts [2, 3], which hatch and develop into gastroenteritis later on. This route allows the outbreaks between dogs and humans frequently, especially in rural areas and shelter canines [7, 8].

It is important to introduce ourselves in the treatment, to comment on the typical clinical signs of the disease, these are due to gastroenteritis [2], due to damage of the villi of the intestine, leading to malabsorption syndrome [8–10], this type of gastroenteritis causes not only typical diarrhea with mucus, odor, and steatorrhea, but also abdominal discomfort, vomiting, nausea, regurgitation, and anorexia. This is why it is important to use drugs that are not only extremely effective (greater than 95% effectiveness) but also the least gastrolesive or irritant.

For the treatment of giardiasis, there are a number of drugs approved by the Food and Drug Administration (FDA), which are described in the Plumb and Papich therapeutic manuals [11, 12]. It is important that it is established which drugs have kinetic studies in animal species, because sometimes pharmacological products are used, which has few studies in domestic species and if we speak of a health picture, not only high morbidity but zoonotic, it should be clear that products can be formulated and what are their therapeutic indications, according to previous studies.

The drugs used for the curative treatment of *G. intestinalis* will be categorized into pharmacological groups, which will indicate their most relevant pharmacological characteristics, such as the mechanism by which the agent is eliminated, its kinetic behavior, contraindications to be taken into account when given, and the dose suggested by the effectiveness studies.

The prevalence of *G. intestinalis* in canines of Colombia is unknown, since the studies described for the canine species are pitifully isolated, whereas in other parts of world, it has been estimated that the prevalence is at 7% and for South America, the prevalence is 27.6%. In Colombia, Alarcón et al. (2015) reported a prevalence of 0.81% in a study with 122 samples of fecal matter in Bogotá, whereas Caraballo et al. (2007) in the center of veterinary medicine and zootechnics CES, Envigado, Colombia, reported a prevalence of 13.9%, compared with research in 22 canine refuges that Sierra-Cifuentes et al. (2015) conducted and a prevalence of 6.8 and 10.3% for the municipality of Medellín and Oriente Antioqueño, respectively.
