Chapter 13-3: Antibiotic Side Effect

TEXTBOOK PRESENTATION

Patients with diarrhea as a side effect of antibiotics typically have watery diarrhea during a course of antibiotics. Upper abdominal symptoms of nausea and vomiting are rare and systemic symptoms should be absent.

DISEASE HIGHLIGHTS

1. Diarrhea complicates up to 25% of antibiotic courses.

2. Although any antibiotic can be associated with diarrhea, those most commonly responsible for diarrhea are:

   1. Clindamycin

   2. Cephalosporins

   3. Ampicillin, amoxicillin, and amoxicillin-clavulanate

3. Patients with diarrhea caused by side effects of antibiotics usually have mild disease that occurs either during or immediately after a course of antibiotics. Possible causes of this type of diarrhea are numerous:

   1. Change in intestinal flora

   2. Nonantimicrobial effect of antibiotics such as the promotility effects of erythromycin.

EVIDENCE-BASED DIAGNOSIS

1. Diarrhea due to antibiotic use is more likely when certain features are present:

   1. History of previous diarrhea associated with antibiotics

   2. Mild to moderate symptoms

2. Symptoms almost always resolve shortly after discontinuation of antibiotics.

TREATMENT

1. Diarrhea as a side effect of antibiotic use usually resolves with discontinuation of antibiotics.

2. Probiotic agents may reduce the risk of antibiotic-associated diarrhea and may shorten an episode once it has occurred.

3. Antidiarrheal agents such as loperamide can provide symptomatic relief.