Warfarin why used

For people with low blood count or cancer: Some cancers can cause internal bleeding. You may have a higher risk of bleeding if you take warfarin. For people who have had head trauma: Warfarin thins your blood.

For people with kidney problems: If you have a history of kidney disease, warfarin increases your risk of serious kidney damage. In addition, you have a higher bleeding risk when taking warfarin. For both of these reasons, your doctor will likely monitor your INR international normalized ratio closely to check how your blood is clotting.

For pregnant women: Warfarin should not be used during pregnancy except in women with mechanical heart valves, who are at high risk of clots. A clot can harm both the mother and the baby. Warfarin should be used during pregnancy only if the potential benefit justifies the potential risk. Women who are breastfeeding: Warfarin may pass through breast milk. Your doctor may give you a lower warfarin dose.

This dosage information is for warfarin oral tablet. All possible dosages and forms may not be included here. Your dose, form, and how often you take it will depend on:. The typical starting dose is 5 mg to 10 mg once per day. Your dose may change over time based on your test and your condition. However, because drugs affect each person differently, we cannot guarantee that this list includes all possible dosages.

Always to speak with your doctor or pharmacist about dosages that are right for you. Warfarin may be a short-term or long-term drug treatment. How long you take this medication depends on your condition. If you skip or miss doses: Stopping or missing doses can cause complications, such as heart attack, stroke, or blood clots in your veins or lungs.

If you take too much: Taking too much warfarin can lead to life-threatening bleeding. Call your doctor or local poison control center or go to the nearest emergency room. What to do if you miss a dose: If you miss a dose, take it as soon as you can. This could result in dangerous side effects. How to tell if the drug is working: You may not feel any different if warfarin is working. However, you may notice reduced bleeding.

Your doctor will do blood tests to see how well the drug is working. Warfarin tablets may be split during therapy. A prescription for this medication is refillable. You should not need a new prescription for this medication to be refilled. Your doctor will write the number of refills authorized on your prescription.

You must have regular blood tests and visits with your doctor to monitor your condition. Some foods and beverages can interact with warfarin and affect your treatment and dosage. While taking this drug, eat a normal, balanced diet, and talk to your healthcare provider before you make any diet changes. Eat consistent amounts of vitamin K-containing food on a week-to-week basis.

Do not eat large amounts of leafy, green vegetables or certain vegetable oils that contain large amounts of vitamin K.

Be sure to talk to your doctor before you make any changes in your diet. Talk to your doctor about eating grapefruit and drinking grapefruit juice while taking this medication. Take the missed dose as soon as you remember it, if it is the same day that you were to take the dose. Do not take a double dose the next day to make up for a missed one.

Call your doctor if you miss a dose of warfarin. You should know that warfarin may cause necrosis or gangrene death of skin or other body tissues.

Call your doctor immediately if you notice a purplish or darkened color to your skin, skin changes, ulcers, or an unusual problem in any area of your skin or body, or if you have a severe pain that occurs suddenly, or color or temperature change in any area of your body.

Call your doctor immediately if your toes become painful or become purple or dark in color. You may need medical care right away to prevent amputation removal of your affected body part.

Warfarin may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.

Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat, moisture not in the bathroom , and light. Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet.

Instead, the best way to dispose of your medication is through a medicine take-back program. It is important to keep all medication out of sight and reach of children as many containers such as weekly pill minders and those for eye drops, creams, patches, and inhalers are not child-resistant and young children can open them easily.

To protect young children from poisoning, always lock safety caps and immediately place the medication in a safe location — one that is up and away and out of their sight and reach. In case of overdose, call the poison control helpline at If the victim has collapsed, had a seizure, has trouble breathing, or can't be awakened, immediately call emergency services at Carry an identification card or wear a bracelet stating that you take warfarin. Ask your pharmacist or doctor how to obtain this card or bracelet.

List your name, medical problems, medications and dosages, and doctor's name and telephone number on the card. They adopted a new in vitro clotting assay using plasma from rabbits to guide chemical fractionation of compounds found in the hay.

In , Link considered using a coumarin derivative as a rodenticide. Dicoumarol acted too slowly to be a practical poison. Link and colleagues worked through a list of variations of coumarin, and number 42 was found to be particularly potent. The compound was named 'warfarin' after the funding agency, and was successfully marketed in as a rodenticide.

In , a US Army inductee attempted suicide with multiple doses of warfarin in rodenticide, but fully recovered after being treated with vitamin K in hospital. Studies then began on the use of warfarin as a therapeutic anticoagulant. Clinical anticoagulants were available at this time, but heparin required parenteral administration, and dicoumarol had a long lag period before onset of a therapeutic effect.

The main advantages of warfarin were high oral bioavailability and high water solubility; it was more potent than dicoumarol, but its effect could still be reversed by vitamin K. Therefore, warfarin transitioned into clinical use under the trade name Coumadin, and was approved for use in humans in An early recipient of warfarin was US president Dwight D.

Eisenhower, who was prescribed the drug after a myocardial infarction in Despite its widespread use, the mechanism of action of warfarin was not discovered until , when John W. Suttie and colleagues demonstrated that warfarin disrupts vitamin K metabolism by inhibiting the enzyme epoxide reductase.

Roderick, L. The pathology of sweet clover disease in cattle. Google Scholar. A problem in the coagulation of blood: 'sweet clover disease of cattle'. Campbell, H. The main side effect of warfarin is bleeding. While the risk of major bleeding is low, you need to be aware of potential problems. For example, you might have trouble stopping the bleeding from a cut on your hand or a nosebleed. More-serious bleeding may occur inside the body internal. Rarely, warfarin can cause the death of skin tissue necrosis.

This complication occurs within a few days of starting warfarin treatment. Seek immediate medical care if you notice any sores, changes in skin color or temperature, or severe pain on your skin.

Some studies suggest that the risk of bleeding is generally higher in the first three months of warfarin treatment.

Older adults are generally at greater risk of bleeding. Taking other blood-thinning medication also increases your risk. Some people who take warfarin are at a higher risk of bleeding because their genetics make them more sensitive to the medication.

Your doctor may recommend a genetic test to determine the best dose for you. Like any other medication, warfarin can interact with certain foods, drugs, vitamins or herbal supplements.

An interaction might lower the effectiveness of warfarin or increase your risk of bleeding. It's important to understand the role of vitamin K in warfarin treatment and a healthy diet. Warfarin works by disrupting the role of vitamin K in a complex series of molecular events that cause blood clotting. But vitamin K is a nutrient essential for heart and bone health. Foods rich in vitamin K are green vegetables, including lettuce, spinach and broccoli.

If you are taking warfarin, the amount of vitamin K in your diet may affect how well the medicine works. If you take warfarin, it's important to have a consistent amount of vitamin K in your diet.

Too little vitamin K can increase your risk of bleeding. Too much vitamin K can decrease warfarin's anti-clotting ability.