A patient calls reporting diarrhea and abdominal cramping after several days of clindamycin, with three days of the course remaining. What is the most appropriate action?

Correct answer: C. Discontinue the clindamycin and contact/refer the patient to a physician for evaluation

• A. Completing the course is the rule for an uncomplicated infection, but it does NOT apply when the antibiotic is causing a potentially serious adverse reaction. Continuing sustains the flora disruption driving C. difficile overgrowth.
• B. Increasing the dose worsens flora disruption and toxicity — never an appropriate response to an adverse drug reaction.
• C. CORRECT. New-onset diarrhea on clindamycin raises concern for CLOSTRIDIOIDES DIFFICILE-associated colitis. The offending antibiotic should be STOPPED and the patient evaluated medically (stool toxin testing; treatment with oral vancomycin or fidaxomicin if positive). Delay here risks progression to pseudomembranous colitis and toxic megacolon.
• D. Probiotics have at best modest preventive value and are not a treatment for established antibiotic-associated colitis. Continuing the culprit drug is the error here.