CYP3A4 and COVID-19: An interval of at least 2 hours between the intake of ampicillin and chloroquine is recommended.28 Hydroxychloroquine has a remarkably long half-life of 40–50 days.29 Multiple drugs being used for the treatment of COVID-19 are CYP3A4 inhibitors which can significantly increase serum chloroquine and hydroxychloroquine (Figure 1).