What time of day should I take warfarin?

I have atrial fibrillation and take Warfarin. I used to take it every morning at the same time as my beta blocker and flecainide and never forgot. When I was in hospital the nurse said Warfarin should be taken at 6pm. This is not convenient as we eat mainly at midday and are out in the evening and twice I have forgotten to take the Warfarin. What difference would it make if I took it in the morning with my other tablets?
Also the anticoagulation clinic told me not to make up the missed dose the next morning - surely it is better than missing a dose completely? I take 5mg weekdays and 6mg at the weekend so obviously the amount is minutely measured and it seems to me that it would be better to make up the missing dose and anyway the 2 doses would be 10 hours apart. I was also told to mark my yellow card with the date of the missing dose althoug my INR test is only monthly now so it seems pointless or perhaps I am not understanding the way warfarin works..

Since Warfarin is rat poison (used in humans as a blood thinner) you should ask your doc and if they are unavailable ask the chemist.
The nurse most likely gave you 6pm due either to some interaction with another med you take at a specific time, or to make it easier on the hospital staff.
No matter what the logic was, consult your physician BEFORE making a change to your current dosing.
Good luck, HTH

I don't understand why the best answer was chosen for me as I carefully chose the answer by onenonblond. It was very comprehensive and helpful. How come this was not registered? Thanks to others for answering all of which have been helpful. Report It

i am on warfarin, i would advise you to take it at night...and i would also advise against missing or making up doses... what is you inr range? that should tell you if you are messing up... i also take it for atrial fibrillation.. by the way you mention anticoagulation clinic...are you in Group Health in puget sound area by any chance?

Never skip a dose and never take a double dose. The dose is based on a blood test called the INR. This can change. Best time to take it is in the evening.

Warfarin is a very difficult drug to regulate as you are aware by having different dosages on particular days. Your dose is designed to keep you at a maintenance blood level over time. For you, at 5 mg every day your level would decline, so getting a 6mg "bump" on the weekends gets you back in theraputic range.

In the hospital setting, it is always given at the dinner hour 5 pm to 6 pm, and the laboratory standards are based on the drug being given at that time.

Once you go home, if you take the drug at a different time, your lab results could be incorrect which could result in your doctor prescribing an incorrect dosage for you.

The reason that your write down missed dosages is because the INR is a ratio of multiple factors, some peak over days and some over hours. It helps your doctor understand if your lab results are unexpected values.

The reason that you skip a missed dose is "calculated risk"...basically, it is less risky to skip a dose and have your value be less than theraputic for a short while, than to double up and have have your clotting time be too long...and risk a bleeding episode. (If one factor peaks at 8 hours, and you take another dose at 10 hours, you hugely increase your blood level....then you go back to regular time, and maintain at a much higher level, which can be very dangerous)

If remembering to take your pill at the "dinner hour" is causing you to miss doses regularly, perhaps you should discuss with your doctor the possibility of taking it at bedtime. Bedtime is a better option than in the morning because it is less time difference to standard dosage time, and longer between dosage and blood draw than taking it in the morning. Most doctors are agreeable to this because taking it at the same time every day is very important. Please discuss it with your own doctor before you make any changes.

Wheew...that's a lot to think about, huh?? That's not all there is!! In fact, this is an extremely simplified explaination but one that should help you understand the reasoning behind the "goofy warfarin rules." I say that because some lab tech may come along behind me and get really technical and confusing. :)

I've attached a link, if you are interested, just as an example of how complicated dosing and testing really is.

Good Luck and Best Wishes to you!!

I have to agree with onenonblonde's advice. Warfarin is generally advised to take at suppertime. If this is an inconvenience then talk to your doctor about taking it at bedtime. Warfarin (Coumadin) is a blood thinner that needs close monitoring with regular PT/INR's. Your physician determines the acceptable parameters you need to be in with this medication. It's vital you take this medication at the same time DAILY or as prescibed by your MD.
The labwork is drawn in the AM, reported to the MD who determines whether your dosage should be adjusted.
Doubling up on a dose is dangerous as it will increase how thin your blood is! Coumadin is cumulative. Sometimes it takes a day or more to regulate a too high or too low PT/INR.
You might want to GOOGLE: Warfarin there are many reputable websites that provide information on this medication. You might want to talk to the anticoagulation clinic to get more information. Armed with knowledge, it may be easier for you to remember to take this medication at the prescibed time.