Unknown herbal powder and a supratherapeutic INR
A 71-year-old woman with atrial fibrillation takes warfarin 3 mg daily; her target INR is 2.0–3.0. She visits a community pharmacy with gum bleeding and new bruises on her arms. A point-of-care INR test in the pharmacy reads 5.8. She has no black stools, no vomiting of blood, and no severe headache. For the past two weeks she has taken a bitter brown herbal powder from a traditional Mongolian healer, one teaspoon twice daily for 'blood circulation and knee pain.' The packet has no ingredient list, only a handwritten label. She also borrowed diclofenac 50 mg tablets from a friend and has taken one twice daily for five days because of knee pain. She asks the pharmacy technician whether she should stop the herbal powder and 'take some vitamin K.'
1. Assess the bleeding risk and the interacting medicines. What should the technician do immediately, and what should not be done without medical direction?
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Risk. INR 5.8 with gum bleeding and bruising is significant over-anticoagulation, even without major bleeding. Diclofenac is a clear contributor: NSAIDs inhibit platelet function, injure gastric mucosa, and can increase warfarin effect, so bleeding risk rises even if the INR were lower. The herbal powder is an unknown; some traditional preparations contain coumarin-like compounds, salicylates, or other substances that affect platelets or warfarin metabolism. The combination is unpredictable, and the label gives no ingredients.
Immediate action. Arrange same-day medical assessment at the anticoagulation clinic or emergency department. Check for severe headache, melena, hematemesis, hematuria, and neurological symptoms; if present, arrange emergency transfer. Do not give vitamin K independently and do not advise stopping warfarin on her own, because reversal and dose decisions depend on the clinician's assessment and stroke risk. If the clinician instructs, the next warfarin dose may be withheld and oral vitamin K considered.
What not to do. Do not tell her the herbal product is 'natural and safe', do not dispense another NSAID, and do not reassure her that a 5.8 INR is acceptable. Do not perform invasive procedures in the pharmacy.
2. Describe the counseling, coordination, and reporting steps, including how to address her questions about stopping the herbal product and taking vitamin K.
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Counseling. Explain that diclofenac and warfarin together increase bleeding, and that the herbal powder's ingredients are unknown and may also interact. Advise her to stop taking diclofenac and not to take more of the herbal powder until the clinician reviews her; these are the modifiable contributors. She should not restart them without discussing with the anticoagulation team. Use paracetamol only if the clinician agrees, and avoid other OTC NSAIDs. Emphasize consistent vitamin K intake and alcohol moderation.
Vitamin K question. Explain that vitamin K reverses warfarin and is used only under medical supervision; taking it on her own could make warfarin ineffective and cause clot risk, and the dose and route depend on bleeding and INR. The clinic will decide.
Coordination and reporting. Contact the anticoagulation clinic, document the INR, bleeding signs, diclofenac and herbal use, and advice given. Ask the healer or patient for the product name, batch, and ingredients; report the suspected warfarin–diclofenac–herbal interaction and the unlabeled herbal product to the national pharmacovigilance center and drug regulator. Arrange a repeat INR and follow-up. If bleeding worsens, seek emergency care.