Warfarin Resistance Due to Sulfasalazine
Bibliographic record
Abstract
OBJECTIVE: To report a case of warfarin resistance associated with the use of sulfasalazine. CASE SUMMARY: A 37-year-old white woman on oral anticoagulant therapy with warfarin was being evaluated for complaints of joint pains. Her past medical history consisted of recurrent deep-vein thrombosis, asthma, and ulcerative colitis. Warfarin concentrations had consistently remained within the therapeutic range with dosages of approximately 30 mg per week. In an attempt to treat arthritis, her gastroenterologist replaced 5-aminosalicylic acid (5-ASA) with sulfasalazine 1000 mg four times daily. Subsequent to the medication changes, the international normalized ratio (INR) decreased and remained at subtherapeutic concentrations despite increases in the warfarin dosage. During this period, the patient developed a deep-vein thrombosis in the right popliteal vein. The INR did not return to an acceptable level until six weeks after sulfasalazine was started. The new warfarin dosage was 75 mg per week, a 250% dosage increase. When sulfasalazine was discontinued and 5-ASA reinstituted, the warfarin dosage requirements to achieve therapeutic INRs returned to weekly dosages of approximately 45 mg. DISCUSSION: Sulfonamides have been well documented to enhance the anticoagulant effect of warfarin. This patient developed a new deep-vein thrombosis due to failure in maintaining therapeutic INR levels after the recent introduction of sulfasalazine. We suspect that she developed warfarin resistance secondary to concomitant use of sulfasalazine. This patient demonstrated warfarin resistance as opposed to enhanced anticoagulant effect with sulfasalazine. CONCLUSIONS: Clinicians managing warfarin therapy should exercise caution when sulfasalazine is added to a patient's medical regimen. This case suggests a possible warfarin-sulfasalazine interaction that resulted in warfarin resistance.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.004 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.003 | 0.002 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".