Indications for prophylactic antibiotics

Indications for prophylactic antibiotics include:

• patients at risk of subacute bacterial endocarditis, for example with mitral valve disease or prosthetic valves
• patients undergoing prosthetic joint or vascular components
• operations which involve contamination to some extent, for example colon or oesophageal resection
• patients who have some other type of indwelling prosthesis, for example total hip replacement

As a general rule prophylactic antibiotics should be given in the perioperative period and then discontinued. It is best if the first dose can be given on induction of anaesthesia. Prolonged administration of antibiotics is accompanied by undesirable side effects, such as the emergence of antibiotic resistant organisms, or the development of pseudomembranous colitis; it is for this reason that a duration of therapy should be stated.