Coumarin Plant Poisoning Follow-up
- Author: Arasi Thangavelu, MD, FACEP, FAAEM; Chief Editor: Asim Tarabar, MD more...
Further Outpatient Care
See the list below:
- Hemodynamically stable adults who take warfarin therapeutically and who have an excessively elevated PT can be monitored closely as outpatients, provided they are in a safe environment and follow-up is arranged.
- Young children who have accidentally ingested a small number of warfarin tablets or rodenticide pellets can be monitored on an outpatient basis. If concern exists regarding the dose, check PT at 24 and 48 hours.
- Inadvertent exposures in adults without complications can be managed likewise.
Further Inpatient Care
Admit all patients with active bleeding or who have intentionally ingested these drugs. Avoid procedures that can precipitate hemorrhage (eg, nasogastric or endotracheal tubes, arterial punctures/line, central lines) unless necessary.
Inpatient & Outpatient Medications
Certain medications and/or foods interfere with warfarin levels in patients who are taking it for therapeutic purposes:
- Ketoconazole: Due to the inhibition of warfarin metabolism by ketoconazole, patients taking high-dose ketoconazole concomitantly with warfarin may need their warfarin dosage reduced by more than is currently recommended, as well as receive more frequent INR monitoring.
- Levofloxacin: An increase in INR seems to occur when levofloxacin and warfarin are concomitantly administered; therefore, close monitoring of INR is advised.
- Cranberry, ginkgo biloba, glucosamine: Consumption of these led to an increase in INR values in a patient receiving warfarin.
- Antiretroviral therapy: INR should be monitored in patients receiving warfarin with concomitant highly active antiretroviral therapy (HAART) that includes either a protease inhibitor or an NNRTI.
- Coenzyme Q, ginseng, St. John’s wort: These have led to decreased warfarin levels and effects.
Patients should contact their doctor for a list of food and medications to avoid. They should notify their doctor if they are consuming any food or medications that are on the doctor’s list that might alter warfarin levels. The doctor might need to conduct dose adjustments for appropriate anticoagulation.
Consider for transfer any patient with life-threatening hemorrhage beyond the capabilities of your facility.
To prevent accidental childhood ingestions, rodenticide should be removed from areas where children have access.
Complications of hydroxycoumarin or rodenticide ingestion may include the following:
Bronstein AC, Spyker DA, Cantilena LR Jr, Green JL, Rumack BH, Giffin SL. 2008 Annual Report of the American Association of Poison Control Centers' National Poison Data System (NPDS): 26th Annual Report. Clin Toxicol (Phila). 2009 Dec. 47(10):911-1084. [Medline].
Ansell J, Hirsh J, Poller L, Bussey H, Jacobson A, Hylek E. The pharmacology and management of the vitamin K antagonists: the Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy. Chest. 2004 Sep. 126(3 Suppl):204S-233S. [Medline].
Mercadal Orfila G, Gracia Garcia B, Leiva Badosa E, Perayre Badía M, Reynaldo Martínez C, Jodar Masanes R. Retrospective assessment of potential interaction between levofloxacin and warfarin. Pharm World Sci. 2009 Apr. 31(2):224-9. [Medline].
Mergenhagen KA, Sherman O. Elevated International Normalized Ratio after concurrent ingestion of cranberry sauce and warfarin. Am J Health Syst Pharm. 2008 Nov 15. 65(22):2113-6. [Medline].
Fulco PP, Zingone MM, Higginson RT. Possible antiretroviral therapy-warfarin drug interaction. Pharmacotherapy. 2008 Jul. 28(7):945-9. [Medline].
Berry RG, Morrison JA, Watts JW, Anagnost JW, Gonzalez JJ. Surreptitious superwarfarin ingestion with brodifacoum. South Med J. 2000 Jan. 93(1):74-5. [Medline].
Chen IS, Chang CT, Sheen WS, et al. Coumarins and antiplatelet aggregation constituents from Formosan Peucedanum japonicum. Phytochemistry. 1996 Feb. 41(2):525-30. [Medline].
Collins Abrams A. Clinical Drug Therapy. 5th ed. Lippincott; 1997.
Hahn A, Oertreich S, Barkin R. Mosby's Pharmacology in Nursing. 16th ed. 1986.
Hardman JG, et al. Goodman and Gilman's the Pharmacological Basis of Therapeutics. 9th ed. Macmillan; 1996.
Hoult JR, Paya M. Pharmacological and biochemical actions of simple coumarins: natural products with therapeutic potential. Gen Pharmacol. 1996 Jun. 27(4):713-22. [Medline].
Klassen C, Amdur M, Doull J. Casarett and Doull's Toxicology. 3rd ed. Macmillan; 1986.
Kruse JA, Carlson RW. Fatal rodenticide poisoning with brodifacoum. Ann Emerg Med. 1992 Mar. 21(3):331-6. [Medline].
La Rosa FG, Clarke SH, Lefkowitz JB. Brodifacoum intoxication with marijuana smoking. Arch Pathol Lab Med. 1997 Jan. 121(1):67-9. [Medline].
Martin EW, et al. Remington's Pharmaceutical Sciences. 13th ed. Mack Publishing Co; 1965.
Ministry of Agriculture, Fisheries and Food (MAFF). Food Surveillance Information Sheets. Survey of biologically active principles in mint products and herbal teas. November 1996. Available at http://archive.food.gov.uk/maff/archive/food/infsheet/1996/no99/99bap.htm. Accessed: December 10, 2004.
Morgan BW, Tomaszewski C, Rotker I. Spontaneous hemoperitoneum from brodifacoum overdose. Am J Emerg Med. 1996 Nov. 14(7):656-9. [Medline].
Mullins ME, Brands CL, Daya MR. Unintentional pediatric superwarfarin exposures: do we really need a prothrombin time?. Pediatrics. 2000 Feb. 105(2):402-4. [Medline].
Olsen KR. Poisoning and Drug Overdose. San Francisco Bay Area Regional Poison Control Center. Norwalk, Conn: Appleton and Lange; 1990.
Pengsuparp T, Serit M, Hughes SH, Soejarto DD, Pezzuto JM. Specific inhibition of human immunodeficiency virus type 1 reverse transcriptase mediated by soulattrolide, a coumarin isolated from the latex of calophyllum teysmannii. J Nat Prod. 1996 Sep. 59(9):839-42. [Medline].
Rosen P. Emergency Medicine Concepts and Clinical Practice. 4th ed. Mosby; 1997.
Rund D, Barkin R, Rosen P. Essentials of Emergency Medicine. 2nd ed. Mosby Lifeline; 1996.
Tintinalli J, Krome R, Ruiz E. Emergency Medicine; A Comprehensive Study Guide. 4th ed. McGraw-Hill; 1995.
Travis SF, Warfield W, Greenbaum BH, Molokisher M, Siegel JE. Spontaneous hemorrhage associated with accidental brodifacoum poisoning in a child. J Pediatr. 1993 Jun. 122(6):982-4. [Medline].
Whyte AC, Gloer JB, Scott JA, Malloch D. Cercophorins A-C: novel antifungal and cytotoxic metabolites from the coprophilous fungus Cercophora areolata. J Nat Prod. 1996 Aug. 59(8):765-9. [Medline].
Williams CA, Goldstone F, Greenham J. Flavonoids, cinnamic acids and coumarins from the different tissues and medicinal preparations of Taraxacum officinale. Phytochemistry. 1996 May. 42(1):121-7. [Medline].