Drug Interaction between Midecamycin and Cyclosporin

Dr. Paul Finielz, Department of Nephrology, CHG Saint-Pierre-Le Tampon, BP350, F-97448 Saint-Pierre Cedex, Réunion Islands (France) 400 -r 350 300 250 200 150 100 50 0 ε 1 s ε < f ü O Fig. 1. Creati-nine (Cr) and serum CsA versus CsA dose regimen (-■-). josamycin has already been described [4], but such a problem has never been pointed out, to our knowledge, with midecamycin. It is of paramount importance to determine CsA blood levels 3 days after the introduction of any medication whose interaction References Pichard L, Fabre I, Fabre G, et al: Cyclosporin: A drug interaction. Screening for inducers and inhibitors of cytochrome P-450 (cyclosporin A oxydase) in primary cultures of human hepato-cytes and in liver microsomes. Drug Metab Dispos 1990;18:595-600. Kessler M, Netter P, Renoult P, et al: Lack of effect of spiramycin on cyclosporin pharmaco-kinetics. Br J Clin Pharmacol 1990;29:370-371. Dear Sir, We report an interaction between ciclo-sporin A (CsA) and midecamycin, a macro-lide antibiotic, in a 53-year-old woman kidney-transplanted 8 months previously following initial polycystic kidney disease. An immunosuppressive drug regimen, predni-sone (10 mg), azathioprine (75 mg) and CsA (120 mg twice) daily, kept her well. Patient characteristics were: 170/80 mm Hg arterial pressure, 47 kg weight, 133 μmol creati-ninemia, whole blood HPLC ciclosporine-mia being 95 ng/ml (therapeutic range: 100-200 ng/ml). A diagnosed amygdalitis led us to add a midecamycin (800 mg twice a day) prescription, because the absence of known interaction of this molecule with CsA and an allergy to betalactamins. Three days later, she complained about edema, tremor and gingival pain. Her characteristics had changed to: 200/100 mm Hg, 49 kg, 150 μmol/l, 380 ng/ml (fig. 1). Midecamycin was maintained at the same dosage, but CsA reduced to 50 mg twice a day. Five days later symptoms had resolved, and CsA blood level has dropped to 150 ng/ml. Following discontinuation of midecamycin, CsA was increased to the previous dosage, i.e. 120 mg twice a day, with CsA blood level remaining stable within therapeutic range.