Low Dose Sucralfate Associated With Significantly Reduced Warfarin INR Response: A Case Report

Sucralfate is a medication that is a chemical complex consisting of aluminum hydroxide and sulfated sucrose. It has been found to cause malabsorption of many different medications, including warfarin, by chelating the drugs within the gastrointestinal (GI) lumen. To minimize potential malabsorption interactions, it is recommended that there be at least a two-hour separation between administration of sucralfate and the second drug. This case report involved a hospitalized patient who was also monitored once discharged, then rechallenged and de-challenged with low dose sucralfate at doses of only 1 gram once daily or 1g twice daily. The case showed that warfarin requirements approximately doubled when the drugs were used concomitantly vs warfarin alone. When the medications were given in the first hospitalization, once daily sucralfate was given at 0900 and warfarin at 2100. Thus, even though the drugs were being separated by about 12 hours, it appears the interaction still manifested. When sucralfate was increased to twice daily in the second hospitalization, it was dosed at 0900 and 2100. Of course, warfarin was also given at 2100 each day for the second admission. Around both hospitalizations, the challenge with sucralfate resulted in subtherapeutic warfarin levels, thereby necessitating dose escalation well above "pre-sucralfate" doses to achieve International Normalized Ratios (INRs) in the therapeutic range of 2-3 for this patient. Also, around both hospitalizations, de-challenge of sucralfate resulted in INRs becoming supratherapeutic in just 2-3 days, yielding INRs of 8.1 after the first discharge and 5.4 after the second discharge.