Anticoagulants: The Dispensing Safety Checklist

📋 First Dispense Essentials

Mandatory items to issue

• Warfarin: issue the yellow anticoagulant treatment booklet and ensure the patient understands the importance of carrying it to appointments and monitoring visits.
• DOACs (apixaban, rivaroxaban, dabigatran, edoxaban): issue an anticoagulant patient alert card appropriate to the prescribed medicine and local practice.
• Ensure the patient has a clear written record of their current dose and indication.

Baseline clinical checks

• Warfarin: baseline international normalised ratio (INR), full blood count, renal function, liver function tests, and blood pressure.
• DOACs: renal function before starting. Dose adjustment or contraindication may apply at lower estimated glomerular filtration rate (eGFR) values depending on the medicine.
• Liver function should be assessed before starting any DOAC. Significant hepatic disease associated with coagulopathy may affect suitability.
• Weight should be documented if relevant to dosing.
• Confirm the indication (atrial fibrillation, venous thromboembolism, or other) as this determines dose and duration.

Key risks and lifestyle traps

• Warfarin and antibiotics: metronidazole, fluconazole, erythromycin, ciprofloxacin, trimethoprim, and co-trimoxazole can significantly increase INR and bleeding risk. Check for monitoring arrangements and contact the prescriber if required.
• Warfarin and non-steroidal anti-inflammatory drugs (including ibuprofen): avoid where possible due to increased bleeding risk.
• Large or sudden increases in cranberry consumption may affect INR. Advise patients to keep dietary intake consistent and report unusual bleeding.
• Warfarin and green leafy vegetables (spinach, kale, broccoli): consistent intake is acceptable, but sudden large dietary changes may affect anticoagulation control.
• St John's Wort: can reduce DOAC levels and increase thrombosis risk. Avoid with DOACs.
• DOACs and strong cytochrome P450 3A4 or P-glycoprotein inhibitors (for example ketoconazole, clarithromycin, or ritonavir) may increase bleeding risk.
• Alcohol increases bleeding risk with all anticoagulants. Heavy binge drinking can also destabilise INR control in patients taking warfarin.
• Pregnancy: warfarin is teratogenic and DOACs are generally avoided during pregnancy. Refer urgently if a patient is pregnant or planning pregnancy.
• Renal function decline: all DOACs depend partly on renal clearance. Dabigatran is particularly affected. Acute illness causing dehydration may increase drug exposure and bleeding risk.

First dispense script

🔄 Repeat Dispense Screen

Mandatory documentation

• Warfarin: record the current INR value, the date it was taken, the current weekly dose, and the target INR range on the dispensing record.
• If a recent INR is unavailable, contact the anticoagulation service before supplying.
• DOACs: record the date of the last renal function review and flag if overdue.
• Document any new interacting medicines added since the previous dispense.

Ongoing clinical checks

• Warfarin: INR monitoring at least every 12 weeks in stable patients, and more frequently after dose changes, interacting medicines, or illness.
• DOACs: renal function at least annually.
• DOACs: more frequent renal function monitoring may be needed in renal impairment. Refer to prescribing information for guidance.
• Apixaban and rivaroxaban: review dosing if renal function has deteriorated.
• Annual weight review may be helpful where body weight influences dose selection.
• Consider periodic liver function monitoring in accordance with local protocols and clinical circumstances.

Ask the patient at the counter

• "Have you had any unusual bleeding since your last prescription, such as cuts that would not stop, unexplained bruising, blood in your urine, or black stools?"
• "Have you started any new medicines, antibiotics, aspirin, anti-inflammatory medicines, supplements, or herbal remedies since we last spoke?"

Lifestyle and surgical alerts

• Surgery and invasive procedures: patients must inform their surgeon and anaesthetist. Interruption should only occur under specialist guidance. Some warfarin patients may require bridging therapy depending on indication and thrombotic risk.
• Dental treatment: patients must inform their dentist. Many dental procedures can be performed without stopping anticoagulation. Do not advise interruption without appropriate clinical guidance.
• Falls risk: if a patient reports recurrent falls, consider referral for review of the risks and benefits of ongoing anticoagulation.
• Alcohol: consistent moderate intake is preferable to irregular heavy drinking. Binge drinking increases bleeding risk.

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