Drug General Information (ID: DDIHLB04VN)
Drug Name			Enoxacin		Drug Info		Methotrexate		Drug Info
Drug Type		Small molecule				Small molecule
Therapeutic Class		Antiinfective Agents				Antimetabolites
Structure

Mechanism of Enoxacin-Methotrexate Interaction (Severity Level: Moderate)
Competitive inhibition of renal tubular secretion Click to Show/Hide Mechanism Graph
Drug Name		Enoxacin				Methotrexate
Mechanism		Competitive inhibition of renal tubular secretion of methotrexate				Methotrexate
Key Mechanism Factor 1
		Factor Name		Renal tubular secretion
		Factor Description		Renal tubular secretion allows selective transfer of substances from the blood around the capillaries into the renal tubules via filtrate. Drug excretion may be reduced when two drugs compete for renal tubular secretion.
Mechanism Description		Decreased elimination of Methotrexate caused by Enoxacin mediated competitive inhibition of renal tubular secretion

Recommended Action
Management		Caution is advised if quinolones must be used with methotrexate. The authors of the case report recommend that ciprofloxacin and related antibiotics not be coadministered with high-dose methotrexate. During concomitant use, patients should be monitored for altered pharmacologic effects of both drugs and the dosage(s) adjusted accordingly if necessary.

References
1	Johnson EJ, MacGowan AP, Potter MN, et al "Reduced absorption of oral ciprofloxacin after chemotherapy for haematological malignancy." J Antimicrob Chemother 25 (1990): 837-42. [PMID: 2373666]
2	Nesher G, Mates M, Zevin S "Effect of caffeine consumption on efficacy of methotrexate in rheumatoid arthritis." Arthritis Rheum 48 (2003): 571-572. [PMID: 12571869]
3	Dalle JH, Auvrignon A, Vassal G, Leverger G "Interaction Between Methotrexate and Ciprofloxacin." J Pediatr Hematol Oncol 24 (2002): 321-322