Metamizole (Optalgin) impact on anti‑Xa levels in cancer patients on apixaban or rivaroxaban
Impact of Metamizole (Optalgin®) on Anti-Xa Concentrations in Oncology Patients Receiving DOACs
This study will test whether taking metamizole (Optalgin) changes anti‑Xa blood levels in adults with cancer who are taking apixaban or rivaroxaban.
Quick facts
| Phase | Not applicable |
|---|---|
| Study type | Interventional |
| Enrollment | 30 (estimated) |
| Ages | 18 Years and up |
| Sex | All |
| Sponsor | Rambam Health Care Campus Academic / other |
| Locations | 1 site (Haifa) |
| Trial ID | NCT07384013 on ClinicalTrials.gov |
What this trial studies
This interventional pharmacokinetic interaction study enrolls adult oncology patients who are receiving the DOACs apixaban or rivaroxaban and who start or are taking metamizole (Optalgin) at the specified dose. Participants will have anti‑Xa concentrations measured to detect changes potentially attributable to metamizole exposure. Key eligibility includes platelets ≥100×10⁹/L and ECOG performance status <3, while patients with allergies to the drugs or significant GI disorders affecting absorption are excluded. The single-site study is conducted at Rambam Health Care Campus and focuses on short‑term drug interaction effects rather than clinical outcomes like bleeding or thrombosis.
Who should consider this trial
Good fit: Ideal candidates are adults with cancer who are taking apixaban or rivaroxaban and either newly start or currently take metamizole at ≥1 g three times daily, have platelets ≥100×10⁹/L, ECOG <3, and can give informed consent.
Not a fit: Patients who are not on apixaban or rivaroxaban, who have an allergy to metamizole or the DOACs, who have significant GI disorders affecting drug absorption, or who have platelet counts below 100×10⁹/L are unlikely to benefit from this protocol.
Why it matters
Potential benefit: If successful, the study could clarify a drug interaction that would help clinicians adjust anticoagulant management to reduce the risk of under‑ or over‑anticoagulation in cancer patients.
How similar studies have performed: Prior pharmacology reports suggest metamizole can induce hepatic enzymes and may alter levels of drugs metabolized by CYP3A4/P‑gp, but clinical evidence specifically showing effects on DOAC anti‑Xa concentrations in cancer patients is limited.
Eligibility criteria
Show full inclusion / exclusion criteria
Inclusion Criteria: * Adult oncology patients (≥18 years old). * Receiving apixaban or rivaroxaban for anticoagulation. * New/current metamizole users taking at least 1g TID for pain management. * Platelets ≥100×10⁹/L * ECOG PS\<3 * Provided informed consent Exclusion Criteria: * History of allergic reaction to metamizole or DOACs. * Individuals with significant gastrointestinal disorders that may affect absorption, including (but not limited to) diagnosed bowel obstruction, persistent diarrhea, or the presence of a nasogastric tube (NGT/zonda)
Where this trial is running
Haifa
- Rambam Health Care Campus — Haifa, Israel (Recruiting)
Study contacts
- Study coordinator: Liat Rappaport
- Email: o_trials@rambam.health.gov.il
- Phone: +97247776234
How to participate
- Review the eligibility criteria above with your treating physician.
- Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
- Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.