How to Conduct a Comprehensive Medication Review for Patients on Anticoagulants
A comprehensive medication review for a patient taking an anticoagulant should do more than identify duplicate medicines. It should establish why anticoagulation is being used, whether the dose remains appropriate, how consistently it is taken, and whether bleeding or clotting risks have changed. The review also provides an opportunity to address practical barriers that may be missed during a short dispensing conversation.
Anticoagulants have different monitoring requirements and risk profiles. Warfarin requires reliable INR testing and careful dose adjustment, while direct oral anticoagulants (DOACs) such as apixaban, rivaroxaban, dabigatran and edoxaban depend heavily on correct dosing, renal function and adherence. A safe review therefore combines clinical records, patient experience, laboratory results and communication with the prescriber.
In Australia, pharmacists may encounter this work through community pharmacy consultations, residential aged care, hospital transitions or a Home Medicines Review (HMR) referral. The PBS, Medicare arrangements, local pathology access and My Health Record can all influence how information is gathered and how quickly recommendations are implemented.
| Review area | Key questions | Possible action |
|---|---|---|
| Indication | Why is anticoagulation prescribed, and for how long? | Confirm diagnosis, duration and prescriber follow-up |
| Dose and suitability | Is the medicine, strength and frequency appropriate for age, weight, kidney and liver function? | Clarify dose or request updated clinical information |
| Adherence | Are doses missed, doubled or taken at inconsistent times? | Simplify routines and provide a written plan |
| Safety | Any bruising, bleeding, falls, anaemia or recent procedures? | Escalate urgent symptoms and review modifiable risks |
| Interactions | Are other medicines, supplements, alcohol or recreational substances involved? | Contact the prescriber and counsel on safer options |
| Monitoring | Are INR, renal function, full blood count and liver tests current when needed? | Arrange testing or recommend a monitoring schedule |
Start with the clinical purpose
Begin by confirming the indication from the dispensing history, referral, discharge summary, specialist letter or GP record. Common reasons include atrial fibrillation, venous thromboembolism, pulmonary embolism, mechanical heart valves and postoperative thromboprophylaxis. The indication affects the target intensity, duration and consequences of interrupted treatment.
Ask whether the patient understands why they take the anticoagulant and what would happen if it were stopped. Someone who describes the medicine as “for my heart” may not realise that missing several doses can increase stroke risk. A person treated for a recent deep vein thrombosis may also be unsure when the planned treatment course ends. Do not assume that an anticoagulant is intended to continue indefinitely.
Check for recent changes in diagnosis, rhythm control, cancer treatment, pregnancy or pregnancy planning, surgery, hospital admission and cardiology review. Mechanical heart valves require particular caution because DOACs are not interchangeable with warfarin for this indication. Any uncertainty about the indication or duration should be resolved with the prescriber rather than inferred from the repeat prescription.
Build an accurate medication picture
Obtain a complete list of prescribed medicines, over-the-counter products, complementary medicines and occasional treatments. Include medicines supplied by different pharmacies, hospital outpatient departments and dose administration aids. In metropolitan areas a patient may use several pharmacies; in regional Queensland, the Northern Territory or rural Western Australia, supply interruptions and travel to pathology services may create additional risks.
Compare the patient’s own list with dispensing records and, where available, My Health Record documents. Ask specifically about aspirin, ibuprofen, naproxen, corticosteroids, antidepressants, antiarrhythmics, antiplatelets and medicines obtained from friends or online sources. Short courses matter: antibiotics, antifungals and oral steroids can change bleeding risk or affect INR control.
Warfarin requires a particularly careful reconciliation of strength, daily dose and dosing schedule. Patients may take different tablet strengths on different days, and an old dose may remain in the home after a change. For DOACs, verify the exact product, frequency and dose reduction criteria. Apixaban and edoxaban dosing, for example, may depend on age, body weight, kidney function or interacting medicines. Dabigatran is strongly dependent on renal clearance.
Record allergies, previous bleeding, falls, anaemia, liver disease, kidney disease and alcohol intake. If a patient raises gambling debts or cash-flow pressure that affects food, transport or medicine purchases, treat it as a medication-safety issue and avoid directing them towards commercial gambling cash-out information.
Assess bleeding and clotting risk
Ask about visible and less obvious bleeding in plain language. Useful prompts include bleeding when brushing teeth, frequent nosebleeds, unusually heavy menstrual bleeding, pink or dark urine, black stools, prolonged bleeding from small cuts, coughing or vomiting blood, and unexplained large bruises. Ask about dizziness, fatigue or breathlessness, which may indicate anaemia even when the patient has not noticed bleeding.
Falls and head injuries deserve specific attention, particularly for older people taking anticoagulants. A fall with a head strike requires prompt medical assessment, even if the patient feels well. Review mobility, footwear, postural symptoms, sedating medicines and the home environment. This is a clinical risk discussion rather than a reason to stop anticoagulation without medical advice.
Assess thromboembolic risk alongside bleeding risk. Ask about missed doses, recent immobilisation, long-distance travel, unilateral leg swelling, sudden breathlessness, chest pain, new neurological symptoms or palpitations. A patient who has stopped treatment because of bruising may need urgent prescriber review, since the danger of interruption can be substantial.
Use a structured bleeding-risk approach where appropriate, but do not treat a score as a substitute for judgement. Modifiable factors may include uncontrolled blood pressure, unnecessary antiplatelet therapy, regular NSAID use, excess alcohol and poor adherence. Australian patients may use terms such as “blood thinners”; clarify that these medicines do not literally thin blood and that their purpose is to reduce clot formation.
Check interactions and practical use
Review pharmacodynamic interactions that increase bleeding, including aspirin, other antiplatelets, NSAIDs, selective serotonin reuptake inhibitors and some systemic corticosteroids. Pharmacokinetic interactions can also alter anticoagulant exposure. Depending on the agent, important examples may include strong CYP3A4 or P-glycoprotein inhibitors and inducers, selected anticonvulsants, rifampicin, certain macrolides and azole antifungals.
For warfarin, investigate changes in antibiotics, amiodarone, thyroid treatment, antiepileptics, alcohol intake and dietary patterns. Consistency is generally more helpful than banning particular foods: sudden major changes in vitamin K intake can affect INR control. The patient should know to report significant illness, diarrhoea, poor appetite and new medicines.
Explore how the medicine fits into daily life. Does the patient work shifts, travel between Perth and a remote community, forget evening doses, struggle with small tablets or rely on a carer? A dose administration aid may help some people, but it must be compatible with the medicine and current pharmacy workflow. Rivaroxaban doses requiring food should be linked to a reliable meal, while missed-dose advice must match the particular product and indication.
Explain what to do if a dose is missed without giving a generic rule for every anticoagulant. Written instructions should state the medicine name, dose, normal timing, missed-dose action and who to contact. Pharmacists can reinforce plain-language counselling with communication practice notes when developing consistent consultation techniques for patients with limited health literacy or limited English.
Monitor, educate and coordinate care
Warfarin monitoring centres on the INR, the patient’s therapeutic range and the dosing plan supplied by the anticoagulation service or prescriber. Check the date and result of the latest INR, the trend over time, the next test and who reviews the result. A result outside range should prompt investigation of adherence, illness, diet, alcohol, interactions and dose changes rather than an automatic recommendation.
DOACs do not require routine INR monitoring to measure their anticoagulant effect, but they do require clinical surveillance. Check whether renal function, liver function, full blood count and weight have been reviewed at suitable intervals. Older adults, people with chronic kidney disease, those with fluctuating health and patients taking interacting medicines may need more frequent reassessment.
Before a procedure, dental extraction or invasive investigation, the patient should know to contact the treating team and disclose the anticoagulant. The interruption plan depends on the medicine, kidney function, bleeding risk of the procedure and indication. Patients should never independently stop treatment because a procedure is approaching.
Provide a bleeding action plan. Minor bruising can be documented and discussed, but heavy bleeding, black stools, vomiting blood, severe headache, fainting, sudden weakness or a head injury require urgent medical care. Include the anticoagulant name and dose in the patient’s wallet, phone health information or medical alert record. Encourage patients to tell every doctor, dentist, nurse and pharmacist about the medicine.
Document, follow up and escalate
A high-quality review records the indication, anticoagulant and dose, adherence pattern, recent monitoring, kidney and liver considerations, bleeding history, interactions, counselling provided and agreed follow-up. Document the patient’s own priorities, such as avoiding another hospital admission, maintaining independence or making travel easier. This makes the review clinically useful rather than a list of disconnected observations.
Communicate recommendations clearly to the GP, cardiologist, anticoagulation clinic or hospital team. State the issue, relevant evidence, potential risk and proposed action. For example, “The patient is taking apixaban 5 mg twice daily but reports a weight below the documented threshold and has no recent renal function result; please confirm dose and arrange testing” is more actionable than “Please review anticoagulant.”
Follow-up should be timed to the risk. A patient with a possible interaction, active bleeding, a new abnormal result or uncertainty about a high-risk dose may need same-day contact. A stable patient who needs adherence support can be reviewed at the next dispensing cycle or scheduled medication consultation. Confirm that recommendations were received and record any resulting dose change.
A comprehensive medication review works best as an ongoing process. Reassess after hospital discharge, acute illness, a fall, a new diagnosis, a change in kidney function, a new medicine or a major change in lifestyle. Community pharmacists are well placed to detect these changes because they often see the patient more frequently than other members of the healthcare team.
Use the next consultation to check the patient’s actual experience, reconcile every medicine again and confirm the monitoring plan. Make anticoagulant safety a shared responsibility across the pharmacy, GP practice, specialist service, pathology provider and patient. Start the review with the current medicine list and indication, act promptly on red flags, and document a follow-up plan that the whole care team can use.