Moderate
Probable
Mô tả
Ciprofloxacin can reduce levothyroxine absorption through complex formation and potential effects on gut motility and transport, risking under-replacement in hypothyroid patients on long courses.
Cơ chế
In vitro and case data suggest ciprofloxacin may form metal ion-mediated complexes with levothyroxine in the GI tract, impairing absorption. Ciprofloxacin may also alter CYP enzymes relevant to T4 deiodination.
Ý nghĩa lâm sàng
Case reports document elevated TSH and symptom recurrence in hypothyroid patients during ciprofloxacin courses; the effect is more pronounced with simultaneous administration.
Xử trí
Administer levothyroxine at least 4 hours apart from ciprofloxacin; monitor TSH if a prolonged ciprofloxacin course (>7 days) is required; dose adjustment may be needed.