Study Notes >> Revision Questions >> Blood & Electrolytes (Preview)
Revision Questions: Blood & Electrolytes (Preview)
- What is the difference between low molecular weight heparins (LMWHs) and heparin?
- What is heparin-induced thrombocytopenia and what may it lead to?
- A patient is admitted to hospital with DVT. The doctor plans to give her warfarin. What are your concerns with starting warfarin?
- What is target INR?
- Provide some counselling points for warfarin.
- LMWHs: longer half life (3-6 hours), given once daily, no monitoring required except platelets, more expensive, risk of heparin-induced thrombocytopenia is lower. Heparin: cheaper, requires 2-3 daily injections, less effective than LMWH in high risk situations.
- Thrombocytopenia is the development of a low platelet count due to the administration of heparin, an anticoagulant. It may occur in <1% of patients in short term use. This will result in bleeding, stroke and/or death.
- Warfarin takes several days to achieve full anticoagulant effect. With the initiation of warfarin, heparin is also given together until the anticoagulant effect of warfarin is established. This usually takes 5-6 days including at least 2 days with the INR in the therapeutic range. Stop heparin when INR is within range and stable.
- 2-3 for all indications except heart valves (seek specialist advice).
- Warfarin counselling:
- Take tablets at about the same time every day; record your dose on a calendar and mark the day off immediately after taking a dose.
- Always take the same brand of tablets. The two available brands are not interchangeable.
- Keep your intake of vitamin K constant. Vitamin K is found in certain foods such as green vegetables and may inhibit the effects of warfarin.
- Avoid excessive alcohol consumption; 1–2 standard drinks per day maximum
- Avoid drinking large amounts of cranberry juice as this may increase the effects of warfarin.
- Warfarin interacts with many medicines. Always tell your doctor and pharmacist that you are taking this medicine before starting or stopping any other medication, vitamin supplement, herbal or OTC product.
- Regular INR testing is recommended. Obtain the result before the next dose so any adjustments can be made. Extra blood tests may be necessary during serious illness.
- Seek immediate medical attention if you notice bruising, bleeding, pink, red or dark brown urine, or red or black stools.
The full version has many more questions with answers included.