Treatment of Giardiasis

Abstract

Giardia lamblia is both the most common intestinal parasite in the United States and a frequent cause of diarrheal illness throughout the world. In spite of its recognition as an important human pathogen, there have been relatively few agents used in therapy. This paper discusses each class of drugs used in treatment, along with their mechanism of action, in vitro and clinical efficacy, and side effects and contraindications. Recommendations are made for the preferred treatment in different clinical situations. The greatest clinical experience is with the nitroimidazole drugs, i.e., metronidazole, tinidazole, and ornidazole, which are highly effective. A 5- to 7-day course of metronidazole can be expected to cure over 90% of individuals, and a single dose of tinidazole or ornidazole will cure a similar number. Quinacrine, which is no longer produced in the United States, has excellent efficacy but may be poorly tolerated, especially in children. Furazolidone is an effective alternative but must be administered four times a day for 7 to 10 days. Paromomycin may be used during early pregnancy, because it is not systematically absorbed, but it is not always effective. Patients who have resistant infection can usually be cured by a prolonged course of treatment with a combination of a nitroimidazole with quinacrine

Fatores associados à ocorrência de parasitoses intestinais em uma população de crianças e adolescentes

“…One of the control strategies usually adopted by the municipal authorities, already described for other regions in Brazil (25) , is the distribution of albendazol, which is also routinely bought by a large number of families in São João del-Rei directly from drugstores, which does not happen in the case of drugs to treat intestinal protozoan infections specifically due to cultural factors. The use of albendazol may be efficacious not only in the treatment of helminthic infections, but also to treat giardiasis (26,27) . The fact that G. lamblia was the least prevalent protozoan in this study supports the hypothesis that prophylactic treatments may have affected prevalence .…”

Additional antiprotozoal flavonol glycosides of the aerial parts of Helianthemum glomeratum

“…For decades the use of metronidazole has been noteworthy for its efficiency; however, potential carcinogenic, teratogenic, embryogenic effects and clinical and laboratory-generated drug-resistant isolates of G. lamblia and E. histolytica have been reported (Upcroft and Upcroft, 2001). Additionally, in prolonged treatment or high doses patients experience headache, vertigo, nausea, dry mouth, metallic taste and, in some cases, neurotoxic side effects (Harris et al, 2000;Gardner and Hill, 2001). In an effort to improve the therapy for giardiasis and amoebic dysentery, medicinal plants used to treat gastrointestinal diseases could be a source of new drugs with high activity and low toxicity.…”

Increased levothyroxine requirement in a woman with previously well-controlled hypothyroidism and intestinal giardiasis

“…Our patient presented a similar evolution: she had been euthyroid during 6 years with stable doses of L-T4 but presented TSH elevation and increased requirement of L-T4 coincident with the onset of abdominal symptoms suggestive of Giardia infection, as well as reduction of that requirement soon after antiparasitic treatment, at least in two separate occasions. Metronidazole (for a week), or single-dose secnidazole or tinidazole are the drugs of choice for giardiasis, with > 90% of cure; other options are albendazole, paromomycin, and nitazoxanide (17).…”