Methotrexate Benzylpenicillin

Bleomycin Bleomycin is incompatible and loses its potency if it is administered with solutions of benzylpenicillin sodium, carbenicillin, cephazolin or cephalothin sodium, hydrocortisone sodium succinate, mitomycin, methotrexate, nafcillin sodium, aminophylline, ascorbic acid, terbutaline, divalent and trivalent cations (especially copper), compounds containing sulfhydryl groups, and precipitation by hydrophobic anions, essential amino acids, riboflavine, dexamethasone, and frusemide. 

Oat2 Benzylpenicillin, erythromycin, tetracycline, rifampicin, glibenclamide, tolbutamide, zidovudine, ganciclovir, digoxin, enalapril, verapamil, methotrexate, acetylsalicylic add... 

Reduced clearance and acute methotrexate toxicity has been attributed to the concurrent use of various penicillins (amoxicillin, benzylpenicillin, carbenicillin, dicloxacillin, flucloxacillin, mezlocillin, oxacillin, penicillin, phenoxymethylpenicillin, piperacillin, ticarcillin) in a small number of case reports. 

Low-dose regimen 7.5 mg weekly Amoxicillin 500 mg orally three times daily for 7 days from day 17, intravenous flucloxacillin 2 g every 4 hours, plus intravenous benzylpenicillin 2 million units every 4 hours Rheumatoid arthritis Neutropenia and thrombocytopenia probably as a result of reduced methotrexate clearance folinic acid given, but patient died 7... 

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