| Abbreviation | Definition |
|---|---|
| RTM | Recall Team Member |
| RTR | Recall Termination Recommendation |
| RU-486 | Roussel Uclaf drug number 486 |
| RUG | resource utilization group |
| RUO | Research Use Only |
| RVIS | Residue Violation Information System |
| RVU | Relative Value Unit |
| Rx | Prescription |
| S&E | Safety and Effectiveness |
| S&I | Standards and Interoperability |
| S/C | Servings per Container |
| S/L | sick leave |
| S/NDS | Supplemental / New Drug Submission |
| SA | Sustained Action |
| SAB | Science Advisory Board |
| SACD | Special Assistant to the Center Director |
| SACS | Scientific Advisors and Consultants Staff |
| SACX | Secretary's Advisory Committee on Xenotransplantation |
| SAD | Single Ascending Dose |
| SADR | Suspected Adverse Drug Reaction |