Warfarin Institute of America

DEDICATED TO YOUR HEALTH SINCE 2000

Phillip Romero, Pharm D Candidate

University of Colorado School of Pharmacy

Saydie and Sally with Mr. Lodwick

Hearing that your child will require warfarin (Coumadin^®) therapy can be a frightening experience for parents. With proper information and counseling most fears can be addressed. Your child’s physician is a great resource for information. Most, if not all, hospitals will provide parents with information on the use of warfarin before discharging a child. If your child requires frequent monitoring of his or her blood, the clinic in which their blood tests are performed is another good source of information. Remember, "there are no dumb questions, the only dumb question is one that is not asked". Your child’s healthcare providers are there to help, so never be afraid to ask a question. With this paper I hope to address questions you may have about warfarin use in children. I have also included stories from parents whose children are on warfarin therapy.

There are many indications for the use of warfarin. The reason a child is placed on warfarin therapy is for the prevention and treatment of thromboembolic complications.¹ Currently, there are no set guideline recommendations for antithrombotic therapy in children. "…Modified adult guidelines remain the primary source for recommendations in children."¹ Children are treated very similarly to adults. Every individual requires patient specific care, so one child with the same condition as another may receive a slightly different treatment regimen. Age is one of the most influential variables in determining the dose a child will receive. Other influential variables include disease state, possible interactions with other medications, and diet.

The way in which a child metabolizes medications is different than that of an adult. The treatment of children "likely differs from adults because of important ontogenic features of hemostasis that affect both the pathophysiology of the throbotic processes and the response to antithrombotic agents."² This is often the case with warfarin. In a recent study conducted by W. Streif and colleagues, warfarin therapy was analyzed in 319 pediatric patients 1 month to 18 years of age. The study participants were divided into 4 age groups (1) one year old and younger; (2) greater than 1 year of age through children under the age of 6; (3) children 6 years of age through children under the age of 13; (4) and the final group consisted of children 13 years of age to 18 years of age.³ The study investigators found that,

Children 1 year of age or younger, as compared with all other ages, required increased warfarin doses, a longer overlap with heparin, longer periods of time to achieve target INR ranges, more frequent INR testing, more dose adjustments, fewer INR values in the target range, and more INR values below the target range."³

These findings were similar in the age group (2), mentioned above, when compared to the older age groups.³ The mechanism responsible for the age dependency of oral anticoagulant doses are not completely clear.^1,2 The duration of therapy with warfarin is similar to durations of therapy in adults with similar disorders.² These findings display the difficulties associated with the management of anticoagulation therapy in younger patients.³ This is one reason why it is so important to comply with all physician directions when administering the medication to your child. If there are any variations in your child’s daily use of the medication it is important to inform the healthcare provider monitoring your child’s INR of such changes. This allows the healthcare provider the information necessary to make recommendations on adjusting your child’s treatment if necessary.

Getting your child into their recommended therapeutic INR range may take several days. Warfarin starts to work within the first 24 hours of taking the first tablet, but can take up to 72 to 96 hours before the drug’s full effects will occur.⁴ In the study performed by W. Streif and colleagues, all children participating in the study achieved their target INR range. A majority of the children, 79%, achieved this in less than 1 week. It should be noted that all children participating in the study received heparin prior to starting warfarin therapy. When compared with the children who took less than 1 week to achieve their target INR, the children that took longer to achieve their target INR levels were often younger and receiving enteral nutrition.³ Enteral nutrition frequently contains vitamin K, a substance that counter acts the effects of warfarin.

Warfarin works by depleting vitamin K dependent clotting factors in the body which are needed by the body to help the blood to form clots.^4,5,6 The less vitamin K you have in your system the slower your blood will clot. At birth, children have 50% lower levels of vitamin K dependent clotting factors and inhibitors than those found in adults.¹ The levels often reach those of adults by the age of 6 months.¹ A misconception patients on warfarin often have is that they cannot eat foods containing vitamin K. Examples of such food are green leafy vegetables (i.e. cabbage, broccoli, lettuce, etc…). It is important to understand that a child taking warfarin can eat foods containing vitamin K as long as they are consistent with they types of foods they eat on a weekly basis. If there are any major changes in your child’s diet it is important to inform the child’s caregiver of the changes. This will allow them to make any necessary adjustments in the warfarin-dosing schedule of your child.

When a patient is at an increased risk for developing a bleed, or a bleeding episode has occurred there are steps a physician can take to remedy the situation. Vitamin K, fresh frozen plasma (FFP), or prothrombin complex concentrates combined with the discontinuation of warfarin therapy are often given to patients with severe bleeds or INR values well above the recommended therapeutic range.⁷ Each patient’s clinical disease state is unique, and it is the clinical problem that will determine which product is administered. Patients are at increased risks for developing bleeds when their INR levels go higher than 5.0.⁷

Persons not taking warfarin will have an INR of 1. Each individual is different, and the type of ailment affecting each individual will determine the recommended INR range he or she will have. The recommended therapeutic target for the treatment and prevention of venous thromboembolsims (VTEs) and pulmonary embolisms (PEs) is an INR of 2.5 with a range between 2.0 – 3.0, and children with mechanical prosthetic heart valves have a recommended therapeutic INR range of 3.0 INR range between 2.5 – 3.5.^1,2,6 These values are extrapolated from the adult guidelines. Lower INR ranges may be warranted in some children depending on their disease state. Low dose warfarin therapy is often used for a variety of reasons with a target INR range of 1.4 – 1.9.¹ At INR levels greater than 5.0 patients are at an increased risk for developing bleeds. More often than not, if a health practitioner is familiar with a patient with an elevated INR, and the person is not bleeding, the physician will often hold their warfarin dose for a couple of days and re-evaluate at that time. For adults, the guidelines recommend administering oral vitamin K₁ 1.0 – 2.5 mg to patients with and INR value between 5.0 to 9.0, and larger doses to patients with an INR value >9.0.⁷ These guidelines vary somewhat in the patient population.¹ The professional recommendation of Al Lodwick, RPh, CACP, and head of anticoagulation services at the hospital in which he works, that vitamin K should be reserved for patients with evidence of bleeding. The reasoning behind this is because vitamin K can reduce a patient’s INR below the recommended therapeutic range, and it is difficult to raise it back up in a timely manner. This can place the patient at risk for developing a clot. It is much easier to treat a bleed than it is a clot. If your child’s INR is out of range, consult the child’s healthcare provider. They advise you on the course of action that should be taken. More often than not, a patient whose INR is out of range will require a slight adjustment in their weekly warfarin dose.

Bleeding is the primary adverse affect associated with anticoagulant medications.^1,2 Bleeding can be divided into two categories: minor bleeding and major bleeding. Minor bleeding that is of little clinical consequence, as defined by clinical guidelines, includes bruising, nosebleeds, heavy menses, coffee-ground emesis, microscopic hematuria, bleeding from cuts and loose teeth, or ileostomy.^1,2 Minor bleeds occurs in approximately 20% of children on oral anticoagulation therapy.¹ Major bleeding is defined as any bleeding requiring professional medical treatment. It is recommended that you contact your child’s physician if they experience any of the following signs or symptoms of a bleed: severe headache, dizziness, or weakness, bleeding from cuts that will not stop, nosebleeds that occur frequently or a nosebleed that will not stop, throwing up blood (coffee-ground emesis), unusual bruising for unknown reasons, red or dark brown urine (hematuria), heavier than usual menses or unexpected bleeding from vagina, yellow skin or eyes, purple discoloration of toes or soles of feet, skin necrosis, and/or unusual pain or swelling.^4,5

Monitoring of children’s INR values is done in the same fashion as adults. A patient’s INR can be obtained via venepuncture or finger sticks. However, children often require more frequent monitoring of the INR values than adults because of differences in diet, medications, primary medical problems, and age distribution.² In a study conducted by V. Marzinotto and colleagues, they measured the accuracy and precision of the CoaguChek (Roche Diagnostics Corp., Indianapolis, IN) capillary whole blood monitoring system in eighty children with various disease states.⁸ In a majority of the cases, less than 70%, the investigators found the CoaguChek INR values differed from the venepuncture values obtained in a laboratory setting by less than 0.5.⁸ The investigators felt the CoaguChek monitoring system is and effective and safe method for monitoring INR values in children. When asked, all patients and parents stated they preferred the CoaguChek method over venepuncture.⁸ In the clinic headed by Al Lodwick, RPh, CACP, the CoaguChek machine is used to monitor both adults and children. The finger stick measurements are periodically assessed against venepuncture measurements to ensure the accuracy of finger stick methods.

If you have any questions relating to warfarin therapy feel free to e-mail them to allodwick@earthlink.net. Questions will be acknowledged within 24 to 48 hours. Do not wait for a reply to a question if it is related to an emergent situation. Take your child to the emergency department, or contact the child’s primary care physician. If you have a story, or experiences you would like to have posted on the website www.warfarinfo.com please feel free to e-mail it to Al Lodwick at the above address.

Madison Six days After Getting An Arotic Valve Implanted

When my wife went in for her 20 week ultrasound, the tech told us it appeared the baby (Later to be known as Madison) had some heart problems. The clinic referred us to a "specialist" in pediatric cardiolgy at Duke University. We went to Duke for a level II ultrasound. After thirty minutes of looking at the echo, the cardioligist told us he could not find anything wrong with the baby, and in his words "Her heart looks perfectly normal" We were RELIEVED! My wife went two weeks late, and her doctor scheduled another ultrasound just to check the babys size. The same ultrasound tech from before looked at the baby and told us "there is something wrong with your babies heart" at which time we became very defensive and told her "you said that at 20 weeks and we went to a specialist at Duke and he said everything was fine". She quite bluntly said "I know you saw the specialist, and what I'm telling you is that he was wrong". They then sent us to East Carolina University to see another Cardioligist, where he correctly diagnosed Madison with TGA, VSD and a coarctation of the Aorta. Madison was born and 2 days later was flown via lifeflight to the Childrens Hospital of Philadephia where she had her first surgery. I shudder to think that if my wife would have delivered on time, our Madison would have been born at the podunk hospital in Goldsboro NC, where some nurse might have misdiagnosed her. If her arterial ductus would have closed, she would not have made it. At ECU they kept the ductus open with medication, allowing her to survive long enough to make it to CHOP for her first surgery. Sometimes we feel like the doctors feel like we ask to many questions, but you know what, oh well. We could quite possibly owe our daughters life to that ultrasound tech at Wayne's womens clinic in Goldsboro NC. I guess it was Gods way of getting us through it, if we had known of her problems during pregnancy, we might have gone crazy. God is handling everything, and has made sure Madison has gotten the care she needs. After her surgery on March 5th, the surgeon told us he could not understand how Madison was thriving with no noticable symptoms, with an aortic valve that was virtually missing one leaflet. I know how, she was in God's hands....period. Trust in God, not in the doctors , they are after all, only human with huge variances in expertise. 

  Madison's Battle Scars 06-99 TGA, VSD, Coarctation of the Aorta Dr. Thomas Spray, Childrens Hospital of Philadelphia 5 Days Old 08-99 Pulmonary Stenosis repair, VSD patch Dr. Kirk Kanter, Childrens Hospital of Atlanta 2 months old 03-04 Aortic Valve Replacement, Dr. Kirk Kanter, Childrens Hospital of Atlanta 23MM St Judes 4 1/2 years old

Sally is a 2-year-old female from Colorado who was placed on Coumadin therapy for the prevention of clot formation often associated with her medical condition. Sally has two mechanical valves located in her heart. She has been on anticoagulation therapy her entire life. Dalila, Sally’s mother, was familiar with Coumadin prior to her daughter’s need for the medication because Sally’s grandmother had been on the medication for some time. Dalila said her previous knowledge of the medication was very helpful in adjusting to her daughter’s need for the medication. The hospital that preformed Sally’s surgeries provided a training course about the use of Coumadin. Dalila indicated this course helped reinforce her knowledge of the medication, and provided some new information on the medication. However, she felt as though the hospital staff were not empathetic to her situation when explaining the reasons why her daughter was being placed on Coumadin. Dalila found the personnel at the anticoagulation clinic were much more helpful in explaining and answering any questions she and her husband had.

Initially, the hardest issue to deal with in her daughter’s Coumadin treatment was watching her child having her blood checked. At first, Sally was not very enthusiastic about having her blood checked, but as time has passed both Dalila and Sally learned to cope with check ups. Dalila said having her mother on the medication allowed Sally to see another person going through the same testing as her.

Although Dalila was familiar with Coumadin prior to her daughter’s use of the medication, she still had many concerns. When I spoke with Dalila three concerns stood out in her mind. Her first concern was the use of the medication in such a young person. She was worried about possible long-term side effect associated with the medication. The second concern she had was knowing how to give the correct amount of the medication to her daughter, since Sally could not swallow or chew the tablets when they were first prescribed. She did not know if her Sally was getting the correct amounts of medication because she had been crushing the tablets and mixing them with Sally’s food. The problem was that Sally did not finish all of her meals. This problem resolved once Sally was able to chew and swallow the tablets. The third concern she had was getting Sally’s INR into therapeutic range. She told me it took several weeks before Sally’s INR was in the desired range. This is not uncommon in patients starting Coumadin. Dalila said the personnel at the anticoagulation clinic were able to address all of her concerns, and as time went on, she and her husband became familiar with the medication and the routine of having their daughter take Coumadin. Today Sally is doing fine, and she is a regular visitor to her anticoagulation clinic.

Ryan is a teenage boy from Colorado who underwent mitral valve replacement early in his life. Ryan’s mother, Debbie, indicated the physicians caring for Ryan refused to perform the surgery because of Ryan’s age, and it would require Ryan to be on Coumadin for the rest of his life. In addition to Ryan being so young at the time, Ryan has Down’s Syndrome. At that time, the physicians felt Ryan would be okay without the valve replacement. As time progressed Ryan’s condition worsened. He was becoming ill more frequently, and he eventually developed pneumonia. It was at this point Debbie was able to convince the physicians to perform the surgery.

Since the surgery Ryan has been doing fine. Debbie indicated that it has been tough, but they’ve managed to work through it. Debbie works in the medical field, so she was able to cope with the surgery, illnesses that have occurred, and medications her son has had to take. Like all mothers, Debbie did have some concerns when her son was first placed on Coumadin. One of the concerns Debbie had was that Ryan would not be able to participate in activities most children participate in. She was worried about the bleeding risks associated with injuries due to physical activities. To this day Ryan has not learned to ride a bicycle, but Debbie did indicate her family tries to keep Ryan as active as possible. It is difficult for Debbie and her family to keep Ryan active because he does not have kids in the neighborhood to play with.

One issue Debbie says she frequently has to deal with is physicians prescribing medications that interact with Coumadin. She constantly has to remind them he is on Coumadin. She said Ryan has taken a few medications that have raised his INR level greater than 8. Normally, she purchases Ryan’s medications from a mail order service, but there are times when she must purchase prescription in town. I recommended to her to inform pharmacists filling new prescriptions for Ryan he is taking Coumadin and if they could make a note of this in his profile. This will alert the pharmacists to look for possible drug-drug interactions each time Ryan has a prescription filled.

One of the toughest hurdles for her family to overcome when Ryan was placed on Coumadin was getting Ryan to the physician’s office for regular blood checks. This was particularly difficult when Ryan was first placed on the medication because he required more frequent monitoring. Eventually, Debbie purchased an anticoagulation blood monitor. With her medical background, she said it was easy for her and her spouse to perform the tests at home. She indicated that any person could learn to use the blood monitors at home. The manufacturer from which she purchased the monitor requires all persons to be trained prior to the purchase of a machine. She said the trainer came to her home and should her how to use the machine. She said purchasing the machine is much more convenient than having to make visits to the clinic every few weeks. I asked her about the cost of the machine, and she said her family paid for the machine out-of-pocket because the insurance company said it was not medically necessary. She indicated the test strips used in the machine are a bit pricey, but the cost of the strips is much lower than the wages she was losing by taking time off from work to make visits to the clinic.

The only major scare Debbie could recall having in relation to Ryan’s use of Coumadin was a bleeding episode that occurred when one of Ryan’s teeth feel out. Ryan’s gums were bleeding on and off for approximately 18 hours. She and her spouse were just about to take Ryan to the emergency department when the bleeding stopped. Other than this incident, Debbie did not mention any other incidents where she has had to take Ryan to the emergency department for Coumadin related emergencies.

Nicholas is a 4 year-old boy from Colorado who was diagnosed with Kawasaki’s Disease with two cardiac aneurysms a few months ago. Shortly after his diagnosis he was place on Coumadin. Mary, Nicholas’s mother, was familiar with Coumadin prior to her son using the medication. Mary’s father had been on Coumadin, so she was able to adjust rather easily to her son’s use of the medication. She did not have many questions about Coumadin when her son was placed on it, but she did have concerns about the medication.

Mary’s biggest worry was that Nicholas would not be able to live an active lifestyle. She was concerned that her son could be injured while playing, and the injury would be amplified due to his Coumadin use. Her worries have subsided over time. Nicholas has had one minor injury while on warfarin. He was running in the kitchen when he slipped and hit his head on a chair. Mary took him into the hospital for an evaluation, and everything was reported as normal.

Like many mothers, Mary is worried about the possible long-term effects of warfarin. It has been the experience of pharmacist Al Lodwick that warfarin has a safe long-term profile. He has cared for numerous patients on long-term warfarin therapy. He cared for one patient who was on warfarin for 43 years, and he has cared for a large number of patients who have been on warfarin 20 years or more. The main side effect, in his experience, that he has seen has been bleeding. Most of the bleeding he has witnessed has been minor.

Angel is a 2-year-old girl from Colorado who underwent aortic valve replacement. Angel’s mother Brittany, and grandmother Jill, both play important roles in Angel’s care. Both help with the needs associated with caring for a child on Coumadin. They both experience the same concerns. Initially, Brittany had a hard time coping with watching Angel getting her finger pricked for INR measurements. It did take some time for her to adjust. Now she does fine watching Angel get checked. At first, Angel had a hard time dealing with having her finger stuck, but now she does just fine. One thing that Brittany did to ease the experience for Angel, as well as other children visiting the clinic, was to provide the clinic with theme Band-Aids (Elmo, Blue’s Clues, etc…). Most children look forward to receiving the theme Band-Aids.

One concern the two had, which I found interesting, involved conflicting information the two received about whether Angel could eat foods containing vitamin K. The nutritionists caring for Angel told them she was not to eat any foods containing vitamin K while Angel’s physician indicated it was okay. They did not know whose advice to follow. I informed them it is okay for Angel to eat foods containing vitamin K as long as she was consistent in the amount she ate on a weekly basis. As long as a person on Coumadin maintains a relatively consistent diet, the healthcare provider monitoring their INR can make any necessary adjustments to their Coumadin dosing. It is important to inform the person monitoring a patient’s INR of any diet, activity, or medication changes that have occurred since their last visit. These types of changes can account for changes occurring in a patient’s INR level.

Other concerns Angel’s mother and grandmother expressed were bleeding, bruising, clotting, and long-term effects of warfarin. To ease there concerns, Al Lodwick described the worse case of bruising he has seen in a child. He described the patient as a young, female who received numerous bruises on her abdomen after playing on a Slip ‘N’ Slide toy. The bruises healed over time, and the girl was all right. Parents must understand that there are risks associated physical activities and warfarin use. Warfarin should not prevent children from participating in all activities. If children are monitored during activities, and parents selecting the activities make sound judgments their children participate in, children should be allowed to play like children.

As time has gone on, and as Brittany and Jill gained experience with the medication, they have come to realize Angel’s Coumadin use is not as unpleasant as it once seemed.

Saydie is a 5-year-old female from Colorado who underwent mechanical mitral valve replacement. Saydie is a very bright young lady. Through the years she has learned what her medication is for and when to take it. In the beginning of her warfarin thearapy, Saydie’s mother found it a little difficult to give Saydie the medication. She started by crushing Saydies’s tablets and placing them into milk. Saydie eventually moved up to taking the medication with her applesauce, then chewing the tablets, and by age four she was able to swallow the tablets.

By the time Saydie reached age 5, she was reminding her mother to give her her medications. She is also very alert to the dangers of her medications. She knows to tell other kids (her cousins) not to play with her medication bottles, and to tell them the medication is not candy.

Sadie is a good example of the knowledge children can display if they are properly informed about their medications. It is important to inform children why they are taking the medication, and the dangers of the medication if not taken as directed. This may be difficult for some, but if you are tactful in your explanation, a child does not have to be afraid of taking their medication.

References:

1. Monagle P, Michelson AD, Bovill E, Andrew M. Antithrombotic therapy in children. Chest 2001; 119:344S-370S.
2. Michelson AD, Bovill E, Andrew M. Antithrombotic therapy in children. Chest 1995; 108(4):506S-522S.
3. Streif W, Marzinotto V, et. al. Analysis of warfarin therapy in pediatric patients: A prospective cohort study of 319 patients. Blood 1999; 94(9):3007-3014.
4. Product Information: Coumadin (A patient’s guide to using Coumadin). Bristol-Myers Squibb Company; 2003.
5. Hutchison TA & Shahan DR (Eds): DRUGDEXÒ System. MICROMEDEX, Greenwood Village, Colorado (Edition Expires [Feb 2005]).
6. Hirsh J, Dalen JE, Anderson DR, et. al. Oral Anticoagulants: mechanism of action, clinical effectiveness, and optimal therapeutic range. Chest 2001; 119:8S-21S.
7. Ansell J, Hirsh J, Dalen J, et. al. Managing oral anticoagulant therapy. Chest 2001; 119:22S-38S.

Marzinotto V, Monagle P, Chan A, et. al. Capillary whole blood monitoring of oral anticoagulants in children in outpatient clinics and the home setting. Pediatr Cardiol 2000; 21:347-352.

©2004 Phillip Romero  Used by permission

CHLOE'S STORY

...'I can’t believe it’s over 3 years since I last wrote about Chloe for the Heartline magazine! I have just sat and read through what I wrote back then and it brought back so many memories – and not many of them good ones! Thankfully, since then, Chloe has gone from strength to strength and is sitting beside me now, a healthy, happy 5 year old.

My reason for updating on Chloe now is to write about our experience of living with a child on warfarin. Since Chloe was started on it at 18 months of age, I have spoken to many parents either dealing with it too or facing the prospect of it and found that the majority of the time, the advice we are given by doctors about it, however medically correct it may be, does not truly reflect what life with a child on warfarin is really like.

I should very briefly explain Chloe’s story again for those who don’t know us.
She was born on 31st October 1999 with a complete AVSD and had her first open heart surgery at Southampton General when she was 6 weeks old to repair the huge hole and to separate her single AV valve into a mitral and a tricuspid. This was only partly successful so in June 2001 when she was just 18 months old and after we came so dangerously close to loosing her, Chloe underwent 3 more surgeries within 3 days, resulting in her own mitral valve being replaced with a 25mm, ‘On-X’, prosthetic valve. This was the start of Chloe’s journey with warfarin (or rat poison as the newspapers like to call it!) and beginning of her new life as a ‘healthy’ child.

Warfarin is basically a drug which slows the blood’s ability to clot. Contrary to popular beliefs, it does not ‘thin’ the blood – a misconception I have fallen for in the past too!
It does have some side effects and limitations on what the children can do but the worst of those that I have experienced are the bruises and bleeding. We have to watch Chloe carefully if she bangs her head or stomach nastily as warfarin can cause internal bleeding in some cases. This can also sound worse than it is when described by doctors. Chloe has had her share of bumped heads and tummies – being the fearing nothing, dare-devil she is – but after quick trips to casualty and a couple of overnight stays, she’s (touching all kinds of wood!!) been fine. She has also looked like one giant walking bruise in the past too, as warfarin does make the children more prone to bruising. Bleeding takes longer to stop with Chloe, due to her bloods slow ability to clot but with a bit of firm pressure, all cuts, scrapes and nose bleeds stop bleeding eventually.
Another thing we have learnt to consider on warfarin is Chloe’s intake of foods high in vitamin K. This is found in high quantities in green vegetables amongst other foods, but that’s not to say she can’t have them (much to her disgust!) – just that we watch how much of them she has and make sure the quantity of them she has is consistent otherwise her INR ends up all over the place.

Which brings me to talk about INR and how we deal with that too. Patients on warfarin need their blood regularly checked to ensure their INR (blood clotting level) is within the levels the doctors want. We aim to keep Chloe’s INR between 3 and 4 whereas a ‘normal’ persons INR would be a level of 1 and children on warfarin for reasons other than a valve replacement would have an INR range somewhere in the middle of the two.

When Chloe first started on warfarin, we had to take her to the local hospital for regular blood tests. These started off at weekly tests and gradually lengthened out to fortnightly, then monthly as her INR became more stable. To say Chloe disliked these blood tests would be a massive understatement. We had screams, nightmares, tears (her and me!) and a one point a HUGE haemotoma on her hand where a nurse did not apply pressure firmly enough after the test! This continued for several months until, with a little help from some friends (namely Hazel Greig-Midlaine and the charity ACE – anti-coagulation Europe) Chloe had a coagu-chek machine donated to her.

(Coagu-chek is a machine for home testing INR – not dissimilar from one used for diabetics.)

I initially had problems with getting trained and started with my machine. Chloe’s cardiac unit at Southampton General, for some unknown reason, had decided not to train anyone on its use that didn’t live in Southampton and since we live in Portsmouth that ruled us out. Our GP didn’t agree with its use and the local hospital refused to help me with dosage etc if I insisted on home testing Chloe’s blood. We weren’t defeated there though. In the end, a lovely rep. from Roche, the makers of Coagu-chek, came out to train me and Southampton eventually agreed to help me out with dosage according to INR if I home tested.
Our coagu-chek machine is excellent!!! I have been using it on Chloe for over 3 years now and it’s proved its accuracy more than once when Chloe has had bloods taken at the local hospital to collaborate results.
No more hospital screaming matches, brusied hands, collapsed veins etc etc. Just a quick needle prick and I have the result in less than 2 minutes. Simple!

Don’t get me wrong though, it’s not all been simple, I have had some very ‘down’ times through Chloe’s treatments and they didn’t stop after the replacement either, but I have now learnt to live with her condition as she does and have long since come to the conclusion that the side effects and restrictions of warfarin are absolutely nothing compared to the life Chloe would have had (had she had one!) without her valve replacement.

I can never stress enough the difference that having that valve replaced made! At her worst coming up to the replacement, Chloe was unable to walk far, she was grumpy and tired, had a cough through CHF and the drug captopril and was getting more and more swollen from fluid due to CHF.
To bring you right up to date now though, Chloe started school in September and LOVES it, she’s very bright, extremely chatty(!!) and is becoming a very keen dancer and swimmer. She doesn’t let her condition rule her life in the slightest and nor do we! She lives life to the fullest and as yet I’ve not found anything I’ve had to stop her doing because of her condition or medications. She goes to parties, plays in the playground with her friends, does PE in school, everything the others do. Obviously as she gets older, there will be some limitations – piercings, tattoos, alcohol and certain contact sports, but for now we are looking forward to celebrating her mechanical valve’s 4th birthday(!) and Chloe is just enjoying life as any other 5 year old… the future will look after itself.'

©2005 Emma Cornish - Used by Permission

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  WARFARIN THERAPY IN CHILDREN ON TOTAL PARENTERAL NUTRITION (TPN) AND OPINIONS ABOUT OTHER PEDIATRIC WARFARIN PATIENTS 

One of the problems with using long-term TPN is that the catheter in the superior vena cava is a foreign object.  This can cause a blood clot to form.  This serious complication can cause this source of nutrition to be abandoned or even cause death.  Warfarin can prevent these clots from forming, but little is known about long-term warfarin use in children.

  Newall et al (Pediatrics.2003;112:E386) studied the results of giving warfarin to eight children who required TPN.  The time studied accounted for 15.2 patient years.  The INR was in the target range 51.1% of the time.  (Editor's note:  This is a fairly good amount of time to be spent in the target range.  At my clinic we average about 58% of the visits being in the desired range.  It is not just the time in range that is important.  How far out of range and how long the person is out of range is important also.)  The target range was an INR of 2.0 to 3.0.  The mean dose of warfarin was 0.33 mg/kg/day.  The mean vitamin K intake was 0.367 mg/kg/day.  (Editor's note: Warfarin works by inhibiting the effects of vitamin K.  However, if you are totally lacking in vitamin K your blood will have a serious clotting deficiency.  Therefore, some vitamin K must be included in the dietary intake.  The higher the amount of vitamin K intake, the higher the warfarin dose will have to be.  In my experience children usually require somewhere between 0.14 and 0.28 mg/kg/day of warfarin.  The amount of warfarin here was not all that much greater than what I have experienced.)  There were no major bleeding events.

  Personally, I have not monitored warfarin for any children with TPN or other central venous access lines.  

  However, I have monitored warfarin for 10 to 15 children between the ages of 5 months and 17 years who have mechanical heart valves or experienced strokes due to clotting disorders.  Fortunately, there have been no serious bleeding or clotting disorders. 

  It is a little more difficult to monitor small children because there is no liquid formulation of warfarin.  The tablet must be finely crushed and place in the feeding bottle just before the product is consumed.  Small children often spit up feedings shortly after intake, making accurate estimation of the dose difficult.  As children age, the dose is then placed in soft foods.  Again whether or not the children actually ingest the entire dose and keep it in their stomach long enough for absorption is subject to interpretation.  The answer for this problem is weekly monitoring until they are old enough for the problem to resolve.  These children seem to be able to swallow whole tablets at remarkable young ages.  This is probably because the caregivers tire of crushing the tablets and encourage swallowing the dose as a whole tablet.

  If a child has a feeding tube, I prefer to give the warfarin dose by the following technique.  Wait until about two hours after the feeding is finished.  Flush the tube with water.  Give the finely crushed tablet with water.  Flush the tube again with water.  Wait about one hour before starting the next feeding.  The reason for this is that the tube feeding formulas are high in fiber.  In adults, giving the warfarin dose too close to the feeding time or flushing the tube with the feeding formula results in the fiber binding the warfarin.  This results in the dose never being absorbed and lost with the fiber in the bowel movement. 

The journal Pediatric Research will be publishing a study by C. Barnes et al showing that 17 children who have been on warfarin for about 8 years had lower spinal bone mineral density that comparable children who were not on warfarin.

I wish I could tell you exactly what this means but I do not know. Apparently they are at increased risk for fracture.

I also wish I could tell you what the treatment is. The obvious answer would be calcium. However, that has not been proven because vitamin K also has a role in bone formation. Since warfarin inhibits the function of vitamin K there may not be an effective treatment.

The authors recommend screening of children but if there is no treatment, I'm not sure what good this will do without a proven treatment.

So why did I start this thread. I guess because it is something to keep in the back of a parent's mind. Calcium might not help but it probably won't hurt. They may need to do some studies with Fosamax.

Keep it in mind but do not be worried about it

  Because so little is known about pediatric patients on warfarin, I will be happy to hear from some parents with various experiences.  This website serves as an informal clearing house for warfarin information.  There have been visitors from over 130 countries.  So I have access to a lot of information that is available nowhere else.

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Last updated July 16, 2007