Adverse events associated with prolonged antibiotic use

Area of Science:

• Pharmacovigilance
• Infectious Disease Epidemiology
• Public Health

Background:

• Current anthrax prophylaxis guidelines recommend 60-day courses of ciprofloxacin, doxycycline, or amoxicillin.
• Severe adverse drug event (ADE) risks associated with these long-term exposures are not well-established due to limited real-world data.

Purpose of the Study:

• To estimate the risks of severe ADEs associated with prolonged exposure to oral antibiotics (ciprofloxacin, doxycycline, amoxicillin).
• To utilize large electronic health record and claims databases for robust ADE risk assessment.

Main Methods:

• Analysis of office visit, hospital admission, and prescription data from three large databases (1999-2001).
• Exposure defined as oral antibiotic person-days (pds); primary outcome was hospitalization with specific ADE diagnoses.
• Random sampling of over 3.3 million patients across the databases.

Main Results:

• Few severe ADEs were observed during long-term antibiotic exposure across all databases.
• Long-term ciprofloxacin showed ADE rates of 5.7 and 3.5 per 100,000 pds in two databases.
• Long-term amoxicillin and doxycycline exhibited very low ADE rates (1.2 and 0.9 per 100,000 pds, respectively).

Conclusions:

• Long-term use of amoxicillin, ciprofloxacin, and doxycycline demonstrates a favorable safety profile.
• These findings support the use of these antibiotics for extended periods in post-exposure anthrax prophylaxis scenarios.