Oral anticoagulants: Safety checks

For all oral anticoagulants, including warfarin, apixaban (Eliquis), dabigatran (Pradaxa) and rivaroxaban (Xarelto), patients should look out for warning signs of a bleed or blood clot between visits.

In addition to monitoring for emergency or worrying side effects (see below), patients need to consider:

• Have any of my medicines been started, stopped or changed?
  
• Have I had any difficulties taking the anticoagulant as prescribed?
  
• Do I need to have surgery or a procedure (including dental)?
  
• Am I planning to to have a baby?
  

For all oral anticoagulants, look out for these side effects^1-3

Emergency side effects

These side effects can be warning signs of a serious bleed or blood clot.

• Blood in the urine or stool
  
• Breathlessness or chest pain
  
• Coughing up or vomiting blood
  
• Dizziness or fainting
  
• Exceptional weakness or unexplained swelling
  
• Heavy menstrual bleeding
  
• Signs of allergy (eg, rash, itching, hives, swelling, wheezing, difficulty breathing)
  
• Numbness in the arms or legs
  
• Oozing from a surgical wound
  
• Prolonged or excessive bleeding (eg, from gums, nose)
  
• Signs of liver problems (eg, yellowing of the skin and/or eyes)
  

Recommendation: Patients should immediately see a doctor, or immediately go to Accident and Emergency at the nearest hospital.

Worrying side effects

These side effects are usually mild.

• Bruising
  
• Constipation
  
• Cough
  
• Diarrhoea, indigestion or stomach pain
  
• Fast heart beat
  
• Fever
  
• Headache
  
• Mild rash or itchy skin
  
• Nausea
  
• Nose bleeds
  
• Pain in the arms or legs
  
• Painful swollen joints
  
• Sore nasal passages or throat
  
• Tiredness, pale skin and breathlessness
  

Recommendation: Patients should immediately tell a doctor if they experience any of these effects.

The non-vitamin K antagonist oral anticoagulants (NOACs) do not require routine anticoagulation monitoring and have fewer food and drug interactions than warfarin does.⁴

However, patients taking a NOAC need to have their kidney function to be monitored throughout treatment.⁵ Kidney function should be checked at least annually, and whenever clinical circumstances or medicines change. If patients have impaired kidney function, monitoring should be more frequent.

It is still also essential to check for potentially harmful drug interactions, contraindications and other patient-related safety factors (such as persistent hypertension, risk of falls, anaemia, and patient adherence) before commencing a NOAC.⁵

Key questions to consider in patients taking a NOAC include:⁵

• Were kidney and liver function assessed when the patient started their NOAC?
  
• Has kidney function been checked in the last year?
  
• Have clinical circumstances or medicines changed?
  
• Has kidney function deteriorated, requiring more frequent monitoring?
  

For related information summaries, see NOAC indications and PBS listings and NOAC metabolism and interactions.

For safe and effective treatment, patients using warfarin need routine anticoagulation monitoring using the international normalised ratio (INR), as well as dose adjustments to compensate for food–drug and drug–drug interactions.⁴

The recommended INR range for patients taking warfarin for treatment of deep vein thrombosis, pulmonary embolism or stroke prevention in atrial fibrillation is 2.0 to 3.0.^4,6-9

Key questions to consider for patients taking warfarin include:¹⁰

• Is the most recent INR within target range?
  
• Are there any factors that may influence the INR (see Tables 1 and 2)?
  
• Have warfarin brands been switched (bioequivalence of warfarin brands has not been established)?
  

Table 1. Endogenous factors that may influence the INR response¹⁰

Table 2. Exogenous factors that may influence the INR response¹⁰

Any patient taking a NOAC or warfarin should understand what the medicine is for, why they are taking it, the dose, and its expected benefits and adverse effects. Patients may consider carrying an alert card so that health professionals are aware they are on anticoagulant treatment.¹¹

They should have a plan for:⁵

• what to do in case of bleeding
  
• what to do if they sustain a serious injury or fall
  
• how often monitoring is needed (if applicable)¹¹
  
• taking medicines as prescribed and what to do if they miss a dose
  
• making any dose adjustments that are required between visits
  
• keeping to any special dietary requirements
  
• regular clinical review by their doctor.