When 2 patients with osteosarcoma, treated with high-dose methotrexate 12 g/m(See reference number 2) per course, were given ciprofloxacin 500mg twice daily, either during or 2 days before start of methotrexate course, methotrexate elimination was delayed, resulting in raised serum levels, severe cutaneous toxicity and renal impairment. The first patient also had hepatic injury and haematological toxicity. Following increased folinic acid rescue,methotrexate levels normalised after several days. In earlier courses without ciprofloxacin in first patient and subsequent courses without ciprofloxacin in second patient, methotrexate elimination was normal (See reference number 1). This preliminary report(See reference number 1) has subsequently been published in full (See reference number 2,3).
Information appears to be limited to one report,but it would seem prudent to monitor for raised methotrexate levels if concurrent use is necessary. More study is needed.
Dalle JH,Auvrignon A, Vassal G, Leverger G. Possible ciprofloxacin-methotrexate interaction: a report of 2 cases. Intersci Conf Antimicrob Agents Chemother (2000) 40, 477.
Dalle JH,Auvrignon A, Vassal G, Leverger G, Kalifa C. Interaction méthotrexate–ciprofloxacine: à propos de deux cas d’intoxication sévère. Arch Pediatr (2001) 8, 1078–81.
Dalle J-H,Auvrignon A, Vassal G, Leverger G. Interaction between methotrexate and ciprofloxacin. J Pediatr Hematol Oncol (2002) 24, 321–2.