Which drug combination is explicitly listed as to avoid due to overdose risk in older adults?

• A. Theophylline + ciprofloxacin
• B. Theophylline + acetaminophen
• C. Theophylline + amoxicillin
• D. Theophylline + aspirin

Answer: (A)

The main concept is that theophylline has a very narrow therapeutic window, so certain drug interactions can push its blood levels into toxic range, especially in older adults whose drug clearance may be reduced. Fluoroquinolones, like ciprofloxacin, can significantly increase theophylline levels by inhibiting its metabolism. When these two drugs are used together, the risk of theophylline overdose rises, leading to symptoms such as nausea, vomiting, tremor, rapid heartbeat, confusion, or even seizures and arrhythmias. This is why the combination is explicitly listed as something to avoid in older adults on the Beers Criteria.

The other drugs listed do not have as strong or as clearly problematic an interaction with theophylline in the Beers Criteria context, so they’re not singled out for overdose risk in the same way. If a patient on theophylline needs an antibiotic, clinicians generally avoid or monitor closely for interactions with fluoroquinolones and consider alternatives.