The cysts can stay infectious for up to three months in cold water.Many people with Giardia infections have no or few symptoms. They may, however, still spread the disease. Pathophysiology
The life cycle of Giardia consists of a cyst form and a trophozoite form. The cyst form is infectious and once it has found a host, transforms into the trophozoite form. This trophozoite attaches to the intestinal wall and replicates within the gut. As trophozoites continue along the gastrointestinal tract, they convert back to their cyst form which is then excreted with feces. Ingestion of only a few of these cysts is needed to generate infection in another host.Infection with Giardia results in decreased expression of brush border enzymes, morphological changes to the microvillus, increased intestinal permeability, and programmed cell death of small intestinal epithelial cells. Both trophozoites and cysts are contained within the gastrointestinal tract and do not invade beyond it.The attachment of trophozoites causes villous flattening and inhibition of enzymes that break down disaccharide sugars in the intestines. Ultimately, the community of microorganisms that lives in the intestine may overgrow and may be the cause of further symptoms, though this idea has not been fully investigated. The alteration of the villi leads to an inability of nutrient and water absorption from the intestine, resulting in diarrhea, one of the predominant symptoms. In the case of asymptomatic giardiasis, there can be malabsorption with or without histological changes to the small intestine.
In 2007, the Committee decided to keep orlistat as a Schedule 3 drug, but withdrew its authorization of direct-to-consumer Xenical advertising, stating this "increased pressure on pharmacists to provide orlistat to consumers...this in turn had the potential to result in inappropriate patterns of use". United States
On 23 January 2006, a U.S. Food and Drug Administration advisory panel voted 11 to 3 to recommend the approval of an OTC formulation of orlistat, to be sold under the brand name Alli by GlaxoSmithKline. Approval was granted on 7 February 2007, and Alli became the first weight loss drug officially sanctioned by the U.S. government for over-the-counter use. Consumer advocacy organization Public Citizen opposed over-the-counter approval for orlistat.Alli became available in the U.S. in June 2007. It is sold as 60 mg capsules—half the dosage of prescription orlistat. European Union and Switzerland
On 21 January 2009, the European Medicines Agency granted approval for the sale of orlistat without a prescription.At least since September 2017, tablets with 60 mg orlistat can be freely sold in Swiss drugstores. Formulations with 120 mg per tablet require a prescription, but can be sold without one in pharmacies under an exemption rule, which is based on a list of easily diagnosable diseases. Generic formulations
U.S. patent protection for Xenical, originally to end on 18 June 2004, was extended by five years (until 2009) by the U.S. Patent and Trademark Office.