رجل عمره ٦٩ سنة عنده انسداد رئوي مزمن، يأخذ ثيوفيلين منذ سنوات بجرعة ثابتة. بدأ قبل أسبوع سيبروفلوكساسين لالتهاب بولي. جاء بغثيان وقيء وخفقان وأرق، والنبض ١٢٨، والضغط ١٣٦/٨٢. ما التفسير الأرجح؟

A 69-year-old man with COPD has taken a stable dose of theophylline for years. A week ago he started ciprofloxacin for a urinary infection. He now has nausea, vomiting, palpitations and insomnia; HR 128, BP 136/82. What is the most likely explanation?

1. An asthma attack needing extra theophylline
2. Theophylline toxicity from a drug interaction
3. An allergy to ciprofloxacin alone
4. A gut infection from the antibiotic

Answer: B) Theophylline toxicity from a drug interaction. Ciprofloxacin inhibits theophylline metabolism and raises its level. Toxicity causes nausea, vomiting, tachycardia, arrhythmias and even seizures. A level is checked and the prescriber informed.