Contraindications
The co-packaged medication is not authorized for the pre-exposure prophylaxis or post-exposure prophylaxis of COVID-19 nor for treatment in those requiring hospitalization due to severe or critical COVID-19, nor for use for longer than 5 consecutive days. The drug is contraindicated in those with hypersensitivity to the two main components, and in those with severely reduced kidney or liver function. During pregnancy
The co-packaged medication is not recommended during pregnancy and in women who can become pregnant and who are not using contraception. Breastfeeding should be interrupted during treatment. These recommendations are because laboratory studies in animals suggest that high doses of the co-packaged medication may affect the growth of the fetus.There are no human data on the use of nirmatrelvir during pregnancy related to the risk of birth defects, spontaneous abortions (miscarriage), or adverse outcomes. There are also no human data on the presence of nirmatrelvir in human milk, its effects on milk production or the infant. In pregnant rabbits, a reduction in fetal body weight was observed with systemic exposure ten times higher than the authorized human dose of the co-packaged medication. A temporary reduction in body weight was observed in the offspring of nursing rats. Interactions and side effects
Co-administration with certain drugs may have serious effects and may sometimes be fatal.
Nirmatrelvir, the novel portion of the co-packaged medication, was first developed in the United States and was initially manufactured in small amounts in Groton, Connecticut, to support clinical trials, but the Freiburg facility in Germany was responsible for figuring out how to mass-produce the co-packaged medication on an industrial scale. Pfizer selected another factory in Ascoli Piceno, Italy, to assist the Freiburg factory with packaging tablets into blister packs. History
The primary data supporting the US Food and Drug Administration (FDA) emergency use authorization for nirmatrelvir/ritonavir are from EPIC-HR, a randomized, double-blind, placebo-controlled clinical trial studying nirmatrelvir/ritonavir for the treatment of non-hospitalized symptomatic adults with a laboratory confirmed diagnosis of SARS-CoV-2 infection. Participants were adults 18 years of age and older with a prespecified risk factor for progression to severe disease or were 60 years and older regardless of prespecified chronic medical conditions. All participants had not received a COVID-19 vaccine and had not been previously infected with COVID-19. The main outcome measured in the trial was the proportion of people who were hospitalized due to COVID-19 or died due to any cause during 28 days of follow-up. Nirmatrelvir/ritonavir significantly reduced the proportion of people with COVID-19 related hospitalization or death from any cause by 88% compared to placebo among participants treated within five days of symptom onset and who did not receive COVID-19 therapeutic monoclonal antibody treatment.