Antibiotic-induced diarrhea

Antibiotics target bacteria causing infection but can also alter the organisms that normally live in the bowel. This change may lead to loose stools, cramping or urgency during treatment or after it finishes. Occasionally, a bacterium called Clostridioides difficile grows after antibiotic exposure and causes more serious bowel inflammation. Symptoms alone cannot reliably identify the cause or show whether the original infection is adequately treated.

Drink regularly and consider an oral rehydration solution if stool losses are substantial. Eat foods you can tolerate and monitor the frequency and appearance of bowel movements. Contact the prescriber before stopping or changing the antibiotic; they may decide to continue it, replace it or investigate another cause. Do not start an anti-diarrheal medicine without advice when there is fever, blood in the stool or significant abdominal pain.

Obtain prompt medical care for bloody or black stool, severe or worsening abdominal pain, a swollen abdomen, repeated vomiting, fever, or frequent watery diarrhea. Urgent assessment is also needed for dehydration signs such as very little urine, dry mouth, dizziness, confusion, fainting or inability to keep fluids down. Tell the clinician about any antibiotic taken recently, even if the course has ended.

Ask whether you should continue the current medicine and whether stool testing is appropriate. Check which fluids, foods and symptom treatments are suitable for you, particularly if you are pregnant, older, immunocompromised or have kidney disease. If another antibiotic is proposed, ask how it addresses both the initial infection and the bowel symptoms.