Patients with specific conditions are prescribed anti-coagulants to prevent the formation of blood clots. While it is regarded as a drug that can help in saving the lives of patients, it could also trigger bleeding through the same mechanism of action that prevents or slows down the formation of blood clots. Consequently, the patient is at risk of experiencing undesirable effects that could be hazardous in nature. Subsequent sections offer a detailed look at the medication, its uses, and the potential side effects of warfarin to help users stay aware of complications and prevent/mitigate any adverse conditions.

Overview of warfarin and its uses

Belonging to the category of anticoagulants, Warfarin is different from medications that belong to the category of antiplatelets. The mechanism of action differs slightly, though both are broadly classified as blood thinners. Warfarin is prescribed for patients who have been diagnosed with certain conditions. For instance, a patient with an artificial heart valve (mechanical) is likely to be exposed to the risk of clotting blood. Similarly, warfarin is also prescribed for patients diagnosed with venous thrombosis; this refers to the formation of a blood clot in the body. Other conditions include pulmonary embolism, wherein blood clots form in the lungs. Patients identified as at risk of having a heart attack, stroke, or damage to organs from blood clots near the heart are also given warfarin. Finally, the medication is also prescribed for patients with arrhythmias, wherein the heart rhythm is inconsistent and could expose the patient to the risk of formation of blood clots.

What happens when blood clots form?

The formation of blood clots, known as thromboses, results in a choking action in the blood vessel. This could be either partial in nature, or it could be complete, and this is known to cause complications that are serious in nature. The narrowing of the arteries and choking of the blood vessels could result in long-term damage or possible fatal conditions such as a heart attack. Blood clots may form in any part of the body; however, the possibility of occurrence is higher in specific areas, and the nature of the outcome depends on the site of thromboses. Conditions that are conducive to the formation of blood clots include the accumulation of fatty deposits.

Mechanism of action of anticoagulants

Warfarin, as a vitamin K antagonist, works by preventing the production of vitamin K, and this, in turn, impacts coagulation.  The broad term of blood thinner given to warfarin is actually not appropriate as the mechanism of action of the medication does not have any impact on the viscosity. Blood clot formation involves the activation of thrombin, and warfarin works by binding to vitamin K, and this, in turn, has an irreversible effect on enzymes, that have a role in the formation of blood clots. This anticoagulation effect can, depending on the dosage and the condition, last for two days.

Side effects of warfarin that occur frequently 

All medications come with the possibility of undesirable effects from the mechanism of action or the properties of the medication. Warfarin is no exception and comes with the possibility of mild, moderate, or adverse effects. The effects may not be the same for all patients and depend on various factors, such as age, gender, the nature of the condition, overall health, existing conditions, and medications in use. It is also necessary to add here that some individuals may not experience any kind of side effects whatsoever. This is essentially a compilation of reported and common effects and is neither exhaustive nor complete.

Frequent – The most frequently reported or documented effect is bleeding, as the medication prevents the formation of blood clots. Consequently, bleeding that is stopped through clotting, will continue without the ability to form blood clots normally. Patients experiencing heavy bleeding may require medical assistance to stem the flow of blood in time before there is severe blood loss.  Nosebleed is another possible undesirable effect of the medication. This is a visible and easily discernible effect that can be identified, with efforts to stop the bleeding. However, there is the possibility of internal bleeding; and this unseen outcome may often remain untreated if not diagnosed or identified in time.

Menstrual bleeding – Patients with certain outcomes are advised to seek urgent and immediate relief in the event of observing or experiencing symptoms listed herein. For instance, women who experience unusually heavy menstrual bleeding when on warfarin are to seek assistance.

Bleeding – Patients who observe discoloration of the urine – either reddish or brownish in color – are to consult the treating specialist at the earliest. Traces of blood in the stool may also have a distinct appearance such as black or tarry stools and this also needs to be treated at the earliest.

Pain – Patients may experience severe pain in the stomach or may experience throbbing headaches. These conditions are to be treated symptomatically, for relief. These conditions or symptoms do not necessarily indicate any other serious underlying outcome. There is also the possibility of pain in the joints or some form of discomfort or swelling in the joints. This is most likely to be experienced after the patient has suffered some kind of injury.

Vomiting and coughing – The patient may vomit up a substance that appears like coffee ground and in some instances, the patient may also vomit blood. Any blood that comes up in vomit needs to be reported to the treating specialist to stem the flow of blood and treat the condition. Similarly, the patient may also cough up blood and this also needs to be treated medically before it turns out of control or is adverse in nature.

Frequent bruising – The patient may end up with frequent bruises without the patient being aware of any injury that could result in bruising. This is a relatively common occurrence, and patients are to seek medical intervention if the bruising and resultant bleeding is heavy. Minor bruises, with little or no bleeding, can be treated locally.

Other effects – Other possible effects that may be experienced include possible dizzy feelings.  The patient may experience overall fatigue and this may have an impact on routines. Weakness arising due to the medication does not have any quick-fix treatment and patients typically cope with the feeling. Dizzy feelings, however, can be managed in a manner so as to prevent other unwanted outcomes. For instance, patients are advised to rise slowly from a resting or reclining position, to avoid falling or losing balance due to the dizzy feeling.

There is also the possibility of the patient experiencing changes in vision as a result of the medication. This also needs to be reported to the treating specialist to prevent it from having a serious impact on the patient. While this could, in most instances be temporary and the problem may resolve for most individuals, there is also the likelihood of it remaining permanent.

Another effect that is a cause for concern is the possibility of the medication having an impact on the skin. Known medically as necrosis, it is essentially the death of skin tissue. This is one of the rare side effects of warfarin and most patients may not experience this. There are clear symptoms that will help in identifying this condition. For instance, the formation of sores after commencing the treatment with warfarin is an indication of the condition. Similarly, any changes in the appearance of the skin, such as color, or any change in skin temperature are also to be considered symptoms of skin necrosis. Pain in the skin is also a possible symptom that indicates necrosis of the skin.

There is the possibility of the patient experiencing bleeding in the gums when brushing teeth. This may occur despite the use of the right kind of brush or less pressure in certain instances and needs to be intimated to the treating specialist. Menstruating women may also experience abnormal bleeding between periods and depending on the volume of blood loss, may require some kind of intervention. Symptoms such as diarrhea and vomiting when experienced by patients for durations in excess of one day need to be treated or managed symptomatically. Patients are known to show a clear dislike to consume food, and when this extends to a long duration, it is necessary to seek a remedy.

Dealing with the undesirable effects

It is possible to reverse or mitigate some of the unwanted outcomes of warfarin. For instance, intravenous administration of vitamin K is a remedial measure to stop bleeding. Other methods include the use of frozen plasma, which is known to reverse the undesirable outcome of warfarin, and medications of the same category. Apart from the above, bleeding is also controlled through the administration of Prothrombin complex concentrate. Finally, protamine sulfate, a blood factor is also part of the treatment protocol to reverse the anticoagulant effect of medications and when there is an inadvertent overdosing of medications of this category. This is especially used when the bleeding is known to be heavy in nature.

Drug interactions and impact

Drug interactions are possible when medications of this category are prescribed along with medications that are known to promote bleeding, diuretics, NSAIDs, and steroids.  In addition to the above, there could be interactions when warfarin is taken along with opioids. Patients on medications to treat certain heart conditions may experience an adverse impact when high doses of warfarin are prescribed. Statin class of medications are also known to trigger unwanted outcomes when taken alongside warfarin. Patients are to exercise caution when on certain antibiotics and when consuming food products that contain high levels of vitamin K.

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