The Food and Drug Administration (FDA) of the United States has approved on Thursday the emergency use of the antiviral pill of the pharmaceutical company Merck to treat patients with coronavirus, a day after doing the same with that of the company Pfizer.The drug developed by Merck has been authorized for use in adults at risk of presenting severe symptoms of the disease due to its clinical picture, although treatment should be given when they are mild or moderate. Unlike Pfizer’s, it cannot be prescribed in children up to twelve years of age. Molnupiravir is available by prescription only and should be started as soon as possible after COVID-19 diagnosis and within five days of symptom onset. The director of the FDA’s Center for Evaluation and Research, Dr. Patrizia Cavazzoni, has stressed that Merck’s drug use will be exclusively intended for those cases in which other treatments are “inaccessible” or “clinically inappropriate.” As new variants of the virus continue to emerge, it is crucial to expand the arsenal of COVID-19 therapies using emergency use authorization, while continuing to collect additional data on their safety and effectiveness,” said Dr. Cavazzoni.Merck trials show that the treatment has reduced the risk of hospitalization and death by up to 30 percent among those most likely to have severe symptoms of Unlike Pfizer,” Merck’s drug was the subject of a previous study last November by a committee of independent FDA experts, which narrowly decided to recommend its use to the agency. The administration of President Joe Biden has sealed a deal with Merck valued at $2.2 billion in exchange for a first batch of about 3.1 million doses, as confirmed this week by white House pandemic response coordinator Jeff Zients, which could be ready as early as January. Each full course of treatment has forty pills, with two batches of four pills of 200 grams every 24 hours for five days. Patients should start the procedure within five days of symptom onset. The FDA, however, has recommended that future patients of this drug use contraceptives while they are under treatment and until at least four days after ingesting the last dose. Possible side effects are diarrhea, nausea and dizziness. In turn, the agency has ruled out its use in children under 18 years of age because of the possibility of affecting their bone growth.