Formularies are lists of antibiotics that are suggested for certain healthcare settings. In developing a recommended formulary, countries should consider the needs of patients and facilities where they receive care. For example, clinicians in rural or primary health centers may need wide access to first-line antibiotics (e.g., penicillin, ampicillin, TMP-SMX), but last resort antibiotics such as carbapenems or colistin might be limited to tertiary care hospitals. Efforts to create antibiotic formularies may be linked to efforts within countries to create or update essential medicine lists (EML).