[11] The most common side effects of baloxavir marboxil include diarrhea, bronchitis, nausea, sinusitis, and headache.

[13] Baloxavir marboxil is an influenza medication, an antiviral,[14][4] for individuals who are twelve years of age or older,[5][14] that have presented symptoms of this infection for no more than 48 hours.

[18][19][20] Baloxavir marboxil should not be co-administered with dairy products, calcium-fortified beverages, or laxatives, antacids, or oral supplements containing calcium, iron, magnesium, selenium, aluminum or zinc.

[22] Baloxavir marboxil is a substituted pyridone derivative of a polycyclic family, whose chemical synthesis has been reported in a number of ways by the company discovering it, Shionogi and Co. of Japan (as well as others); the Shionogi reports have appeared several times in the Japanese patent literature between 2016 and 2019, providing insight into possible industrial synthetic routes that may be in use.

[17][verification needed] Baloxavir marboxil was developed for the market by Shionogi Co., a Japanese pharmaceutical company, and Switzerland-based Roche AG.

[37][better source needed] In October 2018, the FDA approved it for the treatment of acute uncomplicated influenza in people twelve years of age and older who have been symptomatic for no more than 48 hours.

[7][8] Specifically, the FDA approved the use of baloxavir marboxil for people at high risk of developing influenza-related complications.

[1] The safety and efficacy of baloxavir marboxil, an antiviral drug taken as a single oral dose, was demonstrated in two randomized controlled clinical trials of 1,832 subjects where participants were assigned to receive either baloxavir marboxil, a placebo, or another antiviral flu treatment within 48 hours of experiencing flu symptoms.

[7] The safety and efficacy of baloxavir marboxil for post-flu exposure prevention is supported by one randomized, double-blind, controlled trial in which 607 subjects, twelve years of age and older who were exposed to a person with influenza in their household, received either a single dose of baloxavir marboxil or a single dose of a placebo.