Optimal Timing of Ketamine Initiation for SCD Pain

The goal of this clinical trial is to learn if the use of early ketamine decreases the chance of admission to the hospital in patients with sickle cell disease presenting with pain. The main questions this study aims to answer are: * Does ketamine given within 1 hour of acute care presentation decrease the chance of hospital admission? * If admitted, does continuing ketamine in the first few hours of admission decrease opioid use or length of stay compared to those who start it later in the admission? Researchers will compare the study arm to patients with sickle cell disease who receive placebo within 1 hour of presentation for the first aim. Participants will be given ketamine/placebo by mouth without 1 hour of presentation. If admitted, all participants will be able to start open label IV ketamine upon admission to the floor based on their clinical needs. Participants who end up starting ketamine will be reviewed to determine if early start to ketamine is helpful in reducing opioid use and length of stay.