If the casualty is not in shock and can swallow oral medications, they should be given a 400 mg tablet of moxifloxacin.
If the casualty is in shock or unconscious, or cannot swallow oral medications, they should be given one gram of ertapenem.
The logistical issues associated with carrying, reconstituting, and then injecting or infusing parenteral medications makes use of oral antibiotics the preferred route, when oral administration is possible.
Antibiotics must be given as soon as possible after injury to maximize their ability to prevent wound infections.