Warfarin, a New Antibiotic, and a Phone Call at 9:15
At 9:15 am, Mrs. Okafor, 74, calls the front desk. She takes warfarin 5 mg daily; her INR six days ago was 2.4. Three days ago an urgent care clinic prescribed trimethoprim-sulfamethoxazole for a urinary tract infection. This morning her gums bled while she brushed, and yesterday she passed one black, tarry stool. She has no vomiting, no visible blood in the stool today, no fainting, and no shortness of breath. Her last warfarin dose was last night at 8 pm, and the chart lists no allergies. She asks whether she should skip tonight's dose and whether she can take ibuprofen 400 mg for low back pain from gardening. You are the only clinical staff member at the desk; the provider is in with a patient, the nurse is on another line, and the next appointment is at 9:30.
1. How urgent is this call, and what do you do in the next 15 minutes?
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This is urgent but not an automatic 911 call. The combination matters: warfarin plus a newly started antibiotic that inhibits its metabolism, new gum bleeding, and a single episode of melena. That is a plausible early sign of over-anticoagulation and gastrointestinal bleeding, and it will not be safe to park in a routine callback queue.
In the next 15 minutes:
- Put the call on hold politely and tell her you are getting the provider now; do not tell her to call back.
- Interrupt the provider briefly, or if that is impossible, page the nurse line and the on-call clinician per protocol. Give the one-line summary: 74-year-old on warfarin, INR 2.4 last week, TMP-SMX started 3 days ago, gum bleeding, one melena, hemodynamically asymptomatic so far.
- Keep her on the line or ask for a number where she can be reached immediately and whether anyone is with her.
- Escalate to emergency services if she reports dizziness on standing, fainting, vomiting blood, ongoing black stools, chest pain, or shortness of breath.
An MA does not decide the disposition, but an MA does decide whether the message waits until after the 9:30 appointment. It should not.
2. What information must you collect and document before the provider takes over the call?
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Collect the facts the provider will ask for first, so the call does not have to be repeated:
- Warfarin: dose, exact time of the last dose, any missed doses this week, and who manages the INR checks.
- The antibiotic: drug name, dose, start date, doses taken so far, and whether she finished the course.
- Bleeding: what she saw, how much, how long it lasted, whether it stopped, and whether there is bruising, nosebleed, or blood in the urine. Ask specifically about the color and number of stools.
- Other drugs: acetaminophen, NSAIDs, aspirin, other antibiotics, herbal products, fish oil, alcohol intake, and any new prescriptions from another office.
- Symptoms of instability: lightheadedness, palpitations, shortness of breath, weakness, confusion.
- Logistics: best callback number, whether someone is at home, ability to get to a lab or urgent care today, and her pharmacy.
Document the answers in her own words where possible, plus the time of the call, who took it, who was notified, and the time of that notification. If the provider advises an INR today or an emergency evaluation, document that advice and her response.
3. How do you respond to her two questions about skipping tonight's dose and taking ibuprofen, without stepping outside your scope?
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The safe answer is honest about the boundary and still useful to her.
What you may say: 'I am not able to tell you to skip a dose or to take ibuprofen. Both of those decisions belong to your provider, and I am sending your questions to her right now with everything you just told me.'
What you may explain, without advising: NSAIDs such as ibuprofen raise the risk of stomach bleeding and interact with warfarin, and antibiotics like the one she was given can raise the INR. That is general information, not a change to her regimen.
What you must not do: tell her to hold tonight's dose, tell her to take acetaminophen instead, or suggest a dose. Even when the substitute seems obvious, choosing it for a patient on warfarin is a clinical decision.
Document that she asked both questions and that they were referred to the provider, along with the provider's eventual answer and who delivered it. If she runs out of warfarin before the provider responds, that is a separate refill issue to route, not a reason to improvise advice.