Coumadin Nursing Considerations

Last updated on December 31st, 2022 at 11:40 am

Coumadin Nursing Implications

Coumadin Education for Nurses

Coumadin is a prescription blood thinner that prevents normal blood clotting (coagulation). It’s also referred to as an anticoagulant.

In many countries, warfarin is sold under the brand name Coumadin. Many people call coumadin “blood thinners,” even though it does not truly thin the blood. Coumadin makes the blood less prone to clot and prevents them from growing in size and spreading to other parts of the body.

This permits the body’s natural mechanisms to break down a clot over time, lowering the likelihood of clot formation in persons who are at a higher risk of clot formation. Warfarin (Coumadin) prevents and treats significant medical problems caused by blood clots.

The typical clotting mechanism is a multi-step process involving a variety of chemicals (clotting factors). The liver produces these components, which work together to form a blood clot. Adequate levels of vitamin K must be available for the liver to manufacture some of the clotting factors.

Coumadin inhibits one of the enzymes that use vitamin K to generate some clotting factors, reducing their capacity to function properly in the bloodstream. As a result, the clotting mechanism is disturbed, and blood clotting takes longer.

Indications of Warfarin (Coumadin)

  • Prophylaxis and treatment
  • Management of myocardial infarction
    • Decreases risk of death
    • Decreases risk of secondary MI
    • Decreases risk of future thromboembolic incidents
  • Prevention of thrombus formation and embolization following prosthetic valve placement

Mechanism of Action of Coumadin Warfarin

Coumadin is indicated to reduce the regeneration of vitamin K1 epoxide by inhibiting the C1 subunit of the vitamin K epoxide reductase (VKORC1) enzyme complex, hence interfering with clotting factor synthesis.

The severity of depression is influenced by the dosage given and, to some extent, by the patient’s VKORC1 genotype. Coumadin reduces the total quantity of the active form of each vitamin K-dependent clotting factor generated by the liver by 30 to 50 percent at therapeutic doses. Anticoagulation occurs within 24 hours of medication delivery in most cases.

However, the effects of coumadin could intensify. As the effects of daily maintenance doses overlap, they become more prominent. Anticoagulants have little effect on a thrombus that has already formed, and they do not reverse ischemic tissue damage.

However, once a thrombus has formed, anticoagulant medication aims to prevent additional clot extension and secondary thromboembolic problems, which can have serious and sometimes fatal consequences.

Pharmacokinetics of Coumadin Warfarin

Warfarin Coumadin is a racemic mixture of the R- and S-enantiomers. The S-enantiomer shows 2 to 5 times higher anticoagulant activity than the R-enantiomer in humans but generally has a more rapid clearance.

  • Absorption

Coumadin is absorbed almost entirely following oral treatment, with peak concentrations usually occurring within the first four hours.

  • Distribution

There are no differences in the apparent volumes of distribution after intravenous and oral administration of single doses of coumadin solution. Coumadin distributes into a relatively small apparent volume of distribution of about 0.14 liter/kg. A distribution phase lasting 6 to 12 hours is distinguishable after rapid intravenous or oral administration of an aqueous solution. Using a one-compartment model, and assuming complete bioavailability, estimates of the volumes of distribution of R- and S-coumadin are similar to each other and to that of the racemate.

Coumadin concentrations in fetal plasma are similar to maternal levels, however, it has not been identified in human milk (see WARNINGS: Lactation). The medication is attached to plasma proteins to the tune of 99 percent.

  • Metabolism

Coumadin is almost totally eliminated through metabolism. Coumadin is metabolized stereo selectively by hepatic microsomal enzymes (cytochrome P-450) to inactive hydroxylated metabolites (predominant pathway) and reduced metabolites by reductases (coumadin alcohols). The anticoagulant action of coumadin alcohols is quite low. The majority of the metabolites are expelled primarily in the urine, but also in the bile to a lesser proportion. Dehydrocoumadin, two Di stereoisomer alcohols, 4′-, 6-, 7-, 8-, and 10-hydroxycoumadin are among the coumadin metabolites that have been discovered. The isozymes of the cytochrome P-450 family that are involved in the metabolism of coumadin 2C9, 2C19, 2C8, 2C18, 1A2, and 3A4 are among them. 2C9 is most likely the main type of human liver P-450 that regulates coumadin’s anticoagulant action in vivo.

  • Excretion

Coumadin has a terminal half-life of roughly one week following a single dose; however, the effective half-life ranges from 20 to 60 hours, with a mean of about 40 hours. Because the clearance of R-coumadin is half that of S-coumadin and the volumes of distribution are identical, R-coumadin has a longer half-life than S-coumadin. R-coumadin has a half-life of 37 to 89 hours, while S-coumadin has a half-life of 21 to 43 hours. Up to 92 percent of the orally delivered dose is retrieved in urine, according to studies with radiolabeled drugs. Only a small amount of coumadin is eliminated unaltered in the urine. Metabolite excretion is a type of urinary excretion.

Side Effects of Coumadin Warfarin

  • Bleeding, including menstrual bleeding that is heavier than usual
  • Dark red or brown-colored urine
  • Black or blood-colored stool
  • Severe headache or stomach pains
  • Joint pain, stiffness, or edema might occur especially after an injury
  • Vomiting blood or a substance that resembles coffee grounds
  • Coughing up blood.
  • Bruising that appears without a known cause
  • Weakness or dizziness
  • Visual Impairment
  • Head Injury with or without bleeding

Adverse Reactions to Coumadin Warfarin

  • Immune system disorders such as hypersensitivity/allergic responses including urticaria and anaphylactic reactions
  • Vascular diseases such as vasculitis
  • Hepatobiliary diseases including hepatitis and increased liver enzymes – the use of coumadin with ticlopidine at the same time has been linked to cholestatic hepatitis
  • Gastrointestinal disorders including nausea, vomiting, diarrhea, taste aversions, abdominal pain, flatulence, and bloating
  • Skin disorders with rashes, dermatitis (including bullous eruptions), pruritus, and alopecia
  • Respiratory disorders such as tracheal or tracheobronchial calcification
  • Chills

Coumadin Warfarin Overdose

The signs and symptoms of Coumadin overdose include:

  • Blood in the stools or urine
  • Hematuria
  • Severe monthly bleeding
  • Melena
  • Petechiae
  • Excessive bruising or chronic seeping from superficial cuts
  • Unexplained drop in hemoglobin

Drug Interactions with Coumadin Warfarin

Coumadin and other drugs may interact through pharmacodynamic or pharmacokinetic processes. Synergism (impaired hemostasis, lower clotting factor synthesis), competitive antagonism (vitamin K), and change of the physiologic regulatory loop for vitamin K metabolism are the pharmacodynamic pathways for pharmacological interactions with coumadin.

Enzyme induction, enzyme inhibition, and reduced plasma protein binding are the main pharmacokinetic pathways for pharmacological interactions with coumadin. It’s vital to keep in mind that some medications have multiple mechanisms of action.

When starting or quitting other medicines, including herbals, or modifying the dosages of other drugs, especially medications meant for short-term use, more frequent INR monitoring should be done.

  • Drugs that increase the risk of bleeding. Certain medicines are known to enhance the risk of bleeding. Because these medications enhance the risk of bleeding when taken with coumadin, patients taking these drugs should be continuously monitored.
  • Antibiotics and antifungals. Although there have been reports of INR variations in patients taking coumadin plus antibiotics or antifungals, clinical pharmacokinetic studies have not established that these drugs have consistent effects on warfarin plasma concentrations. When starting or terminating any antibiotic or antifungal in individuals taking coumadin, close monitoring of INR is advised.
  • Food and botanical (herbal) products. When starting or quitting herbals, more frequent INR monitoring should be done. There are few sufficient, well-controlled studies examining the metabolic and/or pharmacologic interactions between botanicals and coumadin. The number of active components in botanical medicinal preparations may vary due to a lack of manufacturing standards. This could make assessing potential interactions and anticoagulant effects more difficult. When consumed alone, some botanicals (e.g., garlic and Ginkgo biloba) can cause bleeding and/or have anticoagulant, antiplatelet, and/or fibrinolytic characteristics. These effects are believed to be additive to coumadin’s anticoagulant actions. Some botanicals, on the other hand, may reduce Coumadin’s effects, such as St. John’s wort and ginseng.

The amount of vitamin K in the diet may alter the Coumadin medication. Advise patients to have a healthy, balanced diet with a regular dose of vitamin K. Coumadin patients should avoid making significant dietary changes, such as eating a lot of green leafy vegetables.

Cautions When Using Coumadin Warfarin

  • Hemorrhage. Coumadin has the potential to induce serious or deadly hemorrhage. Within the first month, bleeding is more likely. High anticoagulation (INR >4.0), age greater than or equal to 65, history of highly variable INRs, history of gastrointestinal bleeding, hypertension, cerebrovascular disease, anemia, malignancy, trauma, renal impairment, certain genetic factors, certain concomitant drugs, and long-term warfarin therapy are all risk factors for bleeding. All patients who are being treated should have their INR levels checked on a regular basis. More regular INR monitoring, careful dose adjustment to the desired INR, and the shortest term of medication appropriate for the clinical situation may benefit those at high risk of bleeding. Maintaining an INR in the therapeutic range, on the other hand, does not eliminate the danger of bleeding.
  • Necrosis of Tissue. Skin and other tissue necrosis and/or gangrene are rare but serious risks (0.1 percent). Necrosis, which is often linked with local thrombosis, occurs within a few days of starting coumadin medication. Treatment for severe cases of necrosis has included debridement or amputation of the afflicted tissue, limb, and breast. To evaluate whether necrosis is caused by an underlying condition, a thorough clinical examination is required. Despite the fact that different therapies have been tried, no treatment for necrosis has been found to be consistently successful. If necrosis develops, stop taking coumadin. If anticoagulant therapy must be continued, look into other options.
  • Kidney Injury (Acute). Coumadin may cause acute renal injury in individuals with impaired glomerular integrity or a history of kidney disease, potentially as a result of episodes of severe anticoagulation and hematuria. Anticoagulation should be monitored more often in patients with impaired renal function.
  • Use in pregnant women with mechanical heart valves. When coumadin is given to a pregnant woman, it can harm the fetus. While coumadin is not recommended during pregnancy, the potential advantages of administering it for pregnant women with mechanical heart valves who are at high risk of thromboembolism may exceed the dangers. In some cases, the choice to start or maintain coumadin should be discussed with the patient, taking into account the specific risks and advantages associated with the patient’s medical status, as well as the most recent medical guidelines. coumadin exposure during pregnancy is linked to a pattern of significant congenital abnormalities (coumadin embryopathy and fetotoxicity), fatal fetal bleeding, and a higher chance of spontaneous abortion and fetal mortality. If this drug is used during pregnancy or if the patient becomes pregnant while on it, the patient should be informed of the potential risk to the fetus.
  • Eye surgery. Coumadin use was linked to a significant increase in minor problems such as sharp needle and local anesthetic block in cataract surgery, but not to potentially sight-threatening operational hemorrhagic complications. Because discontinuing or reducing coumadin before comparatively less invasive and sophisticated eye surgery, such as lens surgery, can result in major thromboembolic events, the choice to terminate coumadin should be based on the risks of anticoagulant medication evaluated against the benefits.

Contraindications of Coumadin Warfarin

Coumadin is not recommended for anyone who has/is:

  • Blood dyscrasias or hemorrhagic tendencies.
  • Recent or planned central nervous system or eye surgery, or traumatic surgery with wide-open surfaces.
  • Bleeding tendencies – these have been linked to active ulceration or gastrointestinal, genitourinary, or respiratory tract hemorrhage
  • Central nervous system hemorrhage
  • Dissecting aorta, cerebral aneurysms
  • Pericarditis and pericardial effusions
  • Endocarditis caused by bacteria
  • Pregnant. Coumadin is contraindicated in women who are pregnant, except in pregnant women with mechanical heart valves who are at high risk of thromboembolism. When coumadin is given to a pregnant woman, it can harm the fetus. Coumadin exposure during pregnancy is linked to a pattern of significant congenital abnormalities (warfarin embryopathy and fetotoxicity), fatal fetal bleeding, and a higher chance of spontaneous abortion and fetal mortality. If coumadin is used during pregnancy or if the patient becomes pregnant while taking this medication, the patient should be informed about the risk to the fetus.
  • Eclampsia, preeclampsia, and threatened abortion
  • Patients who are unsupervised and have illnesses that could lead to a high risk of noncompliance
  • Spinal puncture and other diagnostic or therapeutic treatments that may result in uncontrollable bleeding
  • Hypersensitivity to coumadin or any of the product’s other ingredients

Nursing Considerations for Patients taking Coumadin Warfarin

  • Advise the patient to follow the prescribed dosage instructions and schedule.
  • Instruct the patient that if there is a missed dosage of coumadin, the patient should take the dose as soon as possible the next day, but not to take a double dose the next day to make up for missing doses.
  • Obtain and monitor the patient’s prothrombin time.
  • Encourage the patient to adhere to the follow-up schedules with the healthcare provider.
  • Advise the patient that if coumadin therapy is stopped, the anticoagulant effects of coumadin may last for 2 to 5 days.
  • Educate the patient that any activity or sport that could cause traumatic injury should be avoided and if a fall happens, the patient should report it immediately as it may pose a risk to the patient.
  • Educate the patient to maintain a constant dose of vitamin K by eating a healthy, balanced diet and avoid making major dietary changes, such as consuming a lot of leafy green vegetables.
  • Advise the patient to contact the healthcare provider right away if any unusual bleeding or symptoms is present such as pain, swelling, or discomfort from wounds, increased menstrual flow or vaginal bleeding, nosebleeds, bleeding gums from brushing, unusual bleeding or bruises, red or dark brown urine, crimson or tar-black feces, headache, dizziness, or weakness.
  • Inform the patient that Coumadin can induce significant bleeding, which can sometimes result in death. This is due to the fact that coumadin is a blood thinner that reduces the risk of blood clots forming in the body.
  • Advise the patient to reduce the risk of bleedingbecause there is a tendency to bleed more easily than usual while taking coumadin. Some simple measures can decrease this risk. Examples of common-sense precautions include, always using the seatbelt and wearing of a helmet when riding a bicycle or motorcycle,
  • Educate the patient about signs and symptoms of bleeding such as pain, swelling, or discomfort, headaches, dizziness, or weakness, unusual bruising or bruises that develop without a known cause or grow in size, nosebleeds, bleeding gums, bleeding from cuts take a long time to stop, menstrual bleeding or vaginal bleeding that is heavier than normal, pink or brown urine, red or black stools, coughing up blood, vomiting blood or material that looks like coffee grounds and advise the patient to report to the healthcare provider if signs and symptoms of bleeding are present.

Nursing Care Plan for Patients on Coumadin Warfarin

Possible Coumadin Nursing Diagnosis

Risk for Bleeding related to anticoagulant therapy

Decreased Cardiac Output related to potential for bleeding and/or cardiac arrhythmias

Risk for Injury related to clot-dissolving properties of anticoagulant therapy

Fatigue related to Coumadin’s side effect

Deficient Knowledge related to drug action and side effects

Nursing Assessment

Coumadin Nursing InterventionsRationale
Assess the patient for signs and symptoms of atrial fibrillation or blood disorders.To confirm the indication for administering Coumadin.
Check the patient’s allergy status.Previous allergic reactions to Coumadin or warfarin may render the patient unable to take them. Alternatives to anticoagulants should therefore be considered in case of allergy.
Assess if the patient is pregnant or lactating.                                                        Coumadin is generally not prescribed for pregnant women as these drugs can potentially harm the fetus or newborn. However, several common anticoagulants are generally safe while breastfeeding while other anticoagulants are not recommended. Therefore, it is important for the patient to seek advice from her physician regarding the safety of the specific anticoagulant prescribed to her.
When administering oral Coumadin, assess the patient’s mucous membranes and his/her ability to swallow.To check for any potential problems with administration, hydration, and absorption.
Check the patient’s medical history for: Stomach ulceration or any active bleeding ulcersHemorrhagic strokeHemophilia or any other bleeding disordersCerebral aneurysm  Coumadin is contraindicated in patients with the mentioned diseases.
Obtain a list of current medications and their doses from the patient or carer.The patient’s current medications that include antiplatelets or Serotonin Reuptake Inhibitors (SSRIs) should be reviewed and must not be taken in conjunction with anticoagulants due to increased risk for bleeding.  
Obtain blood samples and monitor platelet counts as well as coagulation levels (INR, PT, and PTT).To ensure that the anticoagulant dosing is in line with the target therapeutic range, thus reducing the risk of bleeding. Increased INR, PT and PTT in a patient on anticoagulant therapy means an increased risk for bleeding. This calls for an immediate review of the right dose for the patient.

Nursing Planning and Intervention

Coumadin Nursing InterventionsRationale
Administer oral warfarin (Coumadin) either before or after meals, but always at the same time of the day.To ensure optimal absorption and therapeutic action by anticoagulants. Coumadin is usually given in the evening, but latest research says that there is no significant difference between taking anticoagulants such as warfarin (Coumadin) in the morning or evening, as long as they are taken at the same time of the day in the correct form and dosage.
Educate the patient about the action, indication, common side effects, and adverse reactions to note when taking anticoagulants. Instruct the patient on how to self-administer oral warfarin (Coumadin).To inform the patient on the basics of anticoagulants, as well as to empower him/her to safely self-administer the medication.
Collect urine and stool samples for occult blood testing.Patients on anticoagulant therapy may not show apparent signs and symptoms of bleeding, thus checking for the presence of blood in the stool or urine is an important nursing intervention.
In the event of a bleeding episode due to excessive use of warfarin (Coumadin), administer the appropriate antidote which is Vitamin K as prescribed.Vitamin K is currently used to treat warfarin Coumadin overdose.
Advise the patient to avoid drinking cranberry juice while taking warfarin Coumadin.Cranberry juice can increase the anticoagulant or blood thinning effect of warfarin Coumadin.
Educate the patient to be consistent in incorporating green leafy vegetables, liver, and chickpeas in the diet.Foods rich in vitamin K such as green leafy vegetables (broccoli, parsley, kale, spinach, etc.), liver, and chickpeas can cause interference with the therapeutic action warfarin (Coumadin), particularly decreasing their potency.
Encourage the patient to limit alcohol consumption to 1 to 2 units per day while on warfarin Coumadin.Alcohol may increase the risk of bleeding while the patient is on warfarin Coumadin.
Inform the patient to use a soft-bristled toothbrush and electric razor for hygiene purposes.To prevent injury and lower the risk for bleeding while on warfarin Coumadin.

Nursing Evaluation

Coumadin Nursing InterventionsRationale
Ask the patient to repeat the information about warfarin
To evaluate the effectiveness of health teaching on warfarin Coumadin.
Monitor the cardiovascular and neurological status of the patient.To ensure that the anticoagulants did not cause any cardiac arrhythmias, or other adverse events to the patient.
Monitor kidney and liver function through blood tests for older adults.Older adults are at risk of drug toxicity due to long-term warfarin Coumadin use.
Monitor the patient’s response to anticoagulants in terms of side effects or adverse effects.To check if warfarin Coumadin is effective, the dose needs to be adjusted, or the drug should be stopped and changed to an alternative treatment.

Nursing References

Ackley, B. J., Ladwig, G. B., Makic, M. B., Martinez-Kratz, M. R., & Zanotti, M. (2020). Nursing diagnoses handbook: An evidence-based guide to planning care. St. Louis, MO: Elsevier.  Buy on Amazon

Gulanick, M., & Myers, J. L. (2022). Nursing care plans: Diagnoses, interventions, & outcomes. St. Louis, MO: Elsevier. Buy on Amazon

Ignatavicius, D. D., Workman, M. L., Rebar, C. R., & Heimgartner, N. M. (2018). Medical-surgical nursing: Concepts for interprofessional collaborative care. St. Louis, MO: Elsevier.  Buy on Amazon

Silvestri, L. A. (2020). Saunders comprehensive review for the NCLEX-RN examination. St. Louis, MO: Elsevier.  Buy on Amazon


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This information is intended to be nursing education and should not be used as a substitute for professional diagnosis and treatment.

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Anna Curran. RN, BSN, PHN

Anna Curran. RN-BC, BSN, PHN, CMSRN I am a Critical Care ER nurse. I have been in this field for over 30 years. I also began teaching BSN and LVN students and found that by writing additional study guides helped their knowledge base, especially when it was time to take the NCLEX examinations.

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