Prevention of Complications from Antibiotics
Antibiotics either are cleared by the kidney or detoxified by the liver for elimination by the kidney. Because of this, certain antibiotics should be used with caution in those with either kidney or liver disease, or both. To prevent too low a concentration or, more likely, too high a concentration of antibiotics which can lead to severe side effects, modifying the dosing regime is necessary in these individuals.
Prevention of Anaphylaxis
Those who have experienced an allergic reaction in the past to a specific antibiotic (which would intuitively include other members of its antibiotic family) should never be exposed to that antibiotic family again. Such re-exposure to an immune system “primed and ready” could lead to life-threatening anaphylactic shock. An exception to this is with penicillin therapy in pregnant patients with syphilis, in which the alternatives do not cross the placenta to treat the baby’s simultaneous infection; in these cases, a protocol of desensitization can be done by an allergist until which time penicillin can be given safely to treat both the baby and the mother.
Those with a history of rheumatic fever and/or valvular heart disease could suffer colonization of their valves if bacteria are seeded throughout the bloodstream via invasive procedures, such as surgery, dental work, or invasive testing (biopsies, etc.). These patients will have antibiotics begun before such procedures so that there will be a blood level on board when the theoretical seeding takes place.
Likewise, prophylactic antibiotics are used with indwelling catheters that have a high risk of infection over time, such as Foley bladder catheters, ports for peritoneal dialysis, or central lines.
Prior to placement of gastrostomy tubes or in surgeries that involve patients with a low white blood count or who are immunosuppressed, prophylactic antibiotics are indicated.
Surgeries that involve exposure of a “contaminated” environment to a “clean” environment should have antibiotic prophylaxis that covers the usual bacteria that normally reside in the unsterile areas. An example is a vaginal hysterectomy in which the sterile abdomen is breached to remove the uterus through the vagina. Another example is colon surgery that involves entering the lumen which can spill intestinal bacteria into the abdomen. Some feel that any surgery that involves a skin incision to enter the abdomen, thorax, or cranium, is such a “clean-contaminated” case.
Empiric antibiotic prophylaxis is appropriate in individualized situations specific to the patient. For example, if a man is treated for a sexually transmitted infection (STI), his sexual partner should be treated at the same time due to the likelihood of exposure, even if there are no symptoms. Prevention of recurrence of STIs is based on a culture and sensitivity after a full course of antibiotics, referred to as a “test of cure” (TOC).