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Warfarin · e& Afghanistan

Warfarin

Also sold as: Coumadin

Prescription neededBlood thinners

Comes as:Tablet

Usual adult dose

Dose is set by your doctor and adjusted with regular INR blood tests. Usual adult dose is 2 to 10 mg once a day at the same time each day.

Your doctor may give you a different dose. Children's doses depend on weight.

Side effects

Common

bruising
nosebleeds
bleeding gums

Serious — get help

Stop taking it and see a doctor straight away if you notice:

black stools
blood in urine
vomiting blood
severe headache
bleeding that does not stop

Do not take it, or take care, if

Pregnancy (harms the baby)
Active bleeding or recent bleeding in the brain
Severe uncontrolled high blood pressure
People who cannot have regular INR blood tests
Tell every doctor and dentist that you take warfarin

Interactions

Medicines that can react with this one.

Serious24 medicinesDo not take these together unless your doctor says so.

Amiodarone
Amiodarone strongly raises the effect of warfarin; the warfarin dose usually needs lowering and INR checks.
Aspirin

Pregnancy

A
B
C
D
X

Category X

Must not be used in pregnancy. It can harm the baby.

Generic alternatives

Similar medicines your doctor or pharmacist may offer instead.

Together they greatly raise the risk of serious bleeding.

Carbamazepine lowers the effect of warfarin; INR must be checked.

Can strongly raise the effect of warfarin; INR must be checked.

Together they greatly raise the risk of serious bleeding.

Strongly raises the effect of warfarin and the risk of bleeding; INR must be checked.

Show 18 more

Diclofenac
Raises the risk of serious stomach and other bleeding.
Fenofibrate
Fenofibrate raises the effect of warfarin; the warfarin dose may need lowering and INR checks.
Fluconazole
Fluconazole strongly raises the effect of warfarin; INR must be checked.
Ibuprofen
NSAIDs with warfarin raise the risk of stomach and other serious bleeding.
Indometacin
Raises the risk of serious bleeding.
Ketorolac
Raises the risk of serious bleeding; avoid together.
Mefenamic acid
Raises the risk of serious bleeding.
Meloxicam
Raises the risk of serious bleeding.
Metronidazole
Metronidazole strongly raises the effect of warfarin; INR must be checked.
Miconazole
Miconazole, even as oral gel, strongly raises the effect of warfarin and can cause serious bleeding.
Naproxen
Raises the risk of serious stomach and other bleeding.
Phenobarbital
Phenobarbital lowers the effect of warfarin; INR must be checked.
Phenytoin
Phenytoin changes warfarin levels in both directions; INR must be checked closely.
Piroxicam
Raises the risk of serious bleeding.
Rifampicin
Rifampicin strongly lowers the effect of warfarin; INR must be checked closely.
Rifampicin + Isoniazid
Rifampicin strongly lowers the effect of warfarin; INR must be checked closely.
Rifampicin + Isoniazid + Pyrazinamide + Ethambutol
Rifampicin strongly lowers the effect of warfarin; INR must be checked closely.
Tinidazole
Tinidazole raises the effect of warfarin and the risk of bleeding; INR must be checked.

Moderate33 medicinesTake together only with care. Ask your doctor or pharmacist.

Allopurinol
Allopurinol can increase the effect of warfarin; INR should be checked.
Amoxicillin
Can change the effect of warfarin; INR should be checked during the course.
Amoxicillin + Clavulanic acid
Can change the effect of warfarin; INR should be checked during the course.
Ampicillin
Can change the effect of warfarin; INR should be checked during the course.
Azathioprine
Azathioprine can reduce the effect of warfarin; INR should be checked.
Azithromycin
Can raise the effect of warfarin; INR should be checked.

Show 27 more

Carbimazole
As the thyroid returns to normal, the effect of warfarin can change; INR should be checked.
Cefazolin
Can raise the effect of warfarin and the risk of bleeding; INR should be checked.
Celecoxib
Can raise the effect of warfarin and the risk of bleeding; INR should be checked.
Chloramphenicol
Can raise the effect of warfarin; INR should be checked.
Ciprofloxacin
Can raise the effect of warfarin; INR should be checked.
Citalopram
Citalopram can increase the bleeding risk with warfarin.

Minor5 medicinesUsually not a problem, but tell your doctor.

Cefixime
May slightly raise the effect of warfarin; INR may need checking.
Ceftriaxone
May raise the effect of warfarin; INR may need checking.
Ivermectin
A rise in INR has been reported; check INR if both are used.
Mesalazine
Mesalazine may reduce the effect of warfarin; INR should be checked.
Pantoprazole
INR may change; check it when starting or stopping pantoprazole.

Rivaroxaban

Check with my other medicines

Always follow your doctor or pharmacistThis page is general information, not a prescription. Do not start, stop or change a medicine on your own.

Can lower the effect of warfarin; INR should be checked during the course.

Steroids can change the effect of warfarin; INR should be checked.

Can raise the effect of warfarin; INR should be checked.

Can raise the effect of warfarin; INR should be checked.

Escitalopram can increase the bleeding risk with warfarin.

May increase the effect of warfarin; INR should be checked.

Fluoxetine can increase the bleeding risk with warfarin; INR should be checked.

Griseofulvin can lower the effect of warfarin; INR should be checked.

Used together when starting warfarin, but bleeding risk is higher and needs blood tests.

Ketoconazole tablets can raise the effect of warfarin; INR should be checked.

Can raise the effect of warfarin; INR should be checked.

Starting or changing levothyroxine can increase the effect of warfarin; INR should be checked.

Can raise the effect of warfarin; INR should be checked.

Omeprazole may increase the effect of warfarin; INR should be checked.

Regular high doses of paracetamol can raise the effect of warfarin; INR should be checked.

Paroxetine can increase the bleeding risk with warfarin.

Propylthiouracil

Propylthiouracil can change the effect of warfarin; INR should be checked.

Rosuvastatin can raise the effect of warfarin; INR should be checked when starting.

Sertraline can increase the bleeding risk with warfarin; INR should be checked.

Sucralfate may reduce the effect of warfarin; INR should be checked.

As the thyroid returns to normal, the effect of warfarin can change; INR should be checked.