Sulfafurazole Warfarin

The inhibitory effect of sulfonamides on tolbutamide metabolism is mediated by CYP2C9, and therefore other drugs with narrow therapeutic ranges that are metabolized by CYP2C9, such as phenjhoin and warfarin, deserve attention when certain sulfonamides (for example sulfaphenazole, sulfadiazine, sulfamethizole, and sulfafurazole) are co-administered (215). 

A man taking digitalis, diuretics, antacids and warfarin was later given sulfafurazole 500 mg every 6 hours. After 9 days, his prothrombin time had risen from 20 to 28 seconds, and after 14 days he bled (haematuria, haemoptysis, gum bleeding). His prothrombin time had risen to 60 seconds. ... 

Another patient who had recently started taking warfarin developed haematuria and had a prolonged prothrombin time 7 days after also starting sulfafurazole. ... 

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See also in sourсe #XX -- [ ]

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