Marcumar-Intoxication: The Perils of Near-Homonyms

Introduction: Vitamin-K-antagonists (VKAs) have been a mainstay of anticoagulant therapy for decades. In recent years, they have been displaced by DOAKs in many indications. Regardless, there still is a relevant number of patients treated with phenprocoumon in Germany, underscoring the continued relevance of VKAs [1]. Their use is associated with a significant bleeding risk, especially when overdosed [2]. Preventing accidental overdoses should therefore be a priority.

Method: Here, we present the case of an accidental intoxication with phenprocoumon.

Results: A 59-year-old patient presented to our department with multiple new spontaneous hematomas (image) and a severely deranged INR>8. Analysis of individual coagulation factors showed significantly reduced levels of vitamin K-dependent factors. Thus, the patient received phytomenadione. By the next day, the INR had already normalized. When taking multiple thorough medication histories, the patient denied taking any coumarin-derivatives. We considered an accidental exposure to warfarin-containing rat poison, given her occupation as a cleaner. We also did not want to rule out attempted suicide or poisoning. We involved forensic medicine, the poison control center, and an external toxicology lab to test for rodenticides (coumarins, warfarins, and other vitamin K-antagonists). When we emphasized that external interference could not be ruled out, the patient finally reported daily phenprocoumon (Marcumar®​) intake over the past few days. She had received the preparation as part of an inheritance and had confused it with Curcumin supplement (Turmeric; Curcuma longa) due to the similar names. Curcumin a dietary supplement believed to have health-promoting properties [3]. A few days later the presence of phenprocoumon was confirmed by external laboratory results. After cessation of phenprocoumon-intake the patient fully recovered without any further complications ([Fig. 1]).

Conclusion: VKAs still play an important role in anticoagulation. However, their safety remains a key concern. Accidental overdoses, such as in this case, pose potentially life-threatening bleeding risks. Clear warnings on packaging could possibly prevent future confusion of VKAs with near-homonymous allopathic preparations.

Fig. 1  Spontaneous Hematoma

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Artikel online veröffentlicht:
13. Februar 2025

• References

• 1 Harbrecht U. 1 2011; ‘Old and new anticoagulants’. Hamostaseologie 31 (01) 21-27 Online only: Thieme eJournals
• 2 Levine M, 1 Pizon AF, 1 Padilla-Jones A, 1 Ruha AM. 1 2014. ‘Warfarin overdose: a 25-year experience.’, J Med Toxicol. 10. 02 156-164 Berlin/Heidelberg: Springer;
• 3 Nelson KM, 1 Dahlin JL, 1 Bisson J, 1 Graham J, 1 Pauli GF, 1 Walters MA. 1 2017; ‘The Essential Medicinal Chemistry of Curcumin’, J Med Chem 60 (05) 1620-1637 Online only: American Chemical Society