NSAID's and blood clots

March 13th, 2010
  • Hi, I have a medical situation here that I would like opinions on. The subject has some symptoms of a classic Deep Vein Thrombosis for about a year. These symptoms include swelling of the superficial veins, pain, and swelling of the leg about 3 to 4 inches larger in circumference than the normal leg size for this person. Question 1: Would it be medically competent to prescribe a patient with these symtoms an NSAID, Diclofenac for the leg pain? Here is a link to Diclofencac information: http://www.rxlist.com/cgi/generic/diclofen_ad.htm Of particular interest is the fact that Diclofenac increases Platlet aggregation and can cause statistically signifigant changes in prothrombin and and partial thromboplastin times. It is also stated that "..all drugs that inhibit prostaglandin synthesis interfere with platelet function to some degree; therefore, patients who may be adversely affected by such an action should be carefully observed. " With that being said, with the subject displaying symptoms of a blood clot, or DVT, and also being prescribed Diclofenac, please answer the following questions: Question 2. Could increased platlet aggregation worsen or lead to a DVT condition? Question 3. Could changes in prothrombin and and partial thromboplastin times lead to a worsening or occurance of the DVT condition?


  • There seems to be a little confusion in the question. The asker states that diclofenac increases platelet aggregation. In normal doses it actually decreases platelet aggregation. As stated in the website which the asker cited, it increases platelet aggregation time, which is a lab test of how long it takes the platelets to aggregate, or clump, under specific conditions. Diclofenac inhibits the aggregation, and thus increases the amount of time it takes. In itself this could be helpful for a patient prone to DVTs, as it would make them less likely to occur. However those patients are usually on anticoagulants, most commonly coumadin (warfarin), and adding diclofenac or other NSAIDs, such as ibuprofen, or aspirin, could cause the opposite problem, i.e. inability to clot sufficiently, resulting in uncontrolled bleeding. Patients on coumadin are usually followed closely with lab tests which measure clotting ability and are sensitive to effects of coumadin dose, other medications, and even diet. Thus if the patient is on coumadin it is usually best to avoid other medications which affect bleeding or can affect coumadin levels in the blood. For this reason, it is important for the doctor to be aware of all medications and monitor for interactions. One further note, you state the patient has had symptoms of DVT and wonder if a patient with these symptoms should be put on this medication. The first question should be whether the patient has a DVT or has some other condition which produces the same symptoms. If DVT has been looked for and ruled out, then it shouldn't matter, but if the patient definitely has DVTs the above info would have to be carefully considered. And if the possibility of DVT has not been investigated and either ruled in or out, that needs to be done before prescribing medications. Certainly though, this needs to be brought to the attention of the doctor doing the prescribing, since it is impossible to provide complete and accurate advice without the full information, including examination, etc.


  • Hello tonyvu, Before I begin my answer, I must direct your attention to the disclaimer at the bottom of this page. I must also remind you that this answer is for informational purposes only, and is not intended to replace medical advice from a licensed physician. ==================================================================== Question 1: Would it be medically competent to prescribe a patient with these symtoms an NSAID, Diclofenac for the leg pain? ==================================================================== According to this Arthritis Central site, it is safe to take NSAIDs, including diclofenac sodium, concurrently while taking coumadin. The concern while taking NSAIDs is stomach irritation. Vioxx and Celebrex are know to be milder on the stomach that diclofenac sodium, however. ?In patients who are taking Coumadin as an anticoagulant, only the NSAIDs that are the least irritating to the gastrointestinal tract should be utilized. COX-2 selective inhibitors are preferable, but it is still important to monitor the prothrombin times to make sure that these are not adversely affected. Also, the patient needs to be monitored to make sure that there is no gastrointestinal bleeding while on these medications in combination with an anticoagulant? http://arthritiscentral.com/html/medsnsaids.htm Contrary to the above site, this page, from The Newcastle Upon Tyne Hospitals, says NOT to take NSAIDs, especially diclofen. (Page 5) http://www.newcastle-hospitals.org.uk/v2/PDF/patientleaflets/Haematology/Large/deep%20vein%20thrombosis.pdf If the patient in question IS on anticoagulants, this site recommends avoiding diclofenac (as well as azapropazone, flurbiprofen, indometacin, phenylbutazone, and piroxicam. http://www.netdoctor.co.uk/medicines/showpreparation.asp?id=2796 NSAIDs (Non steroidal anti-inflammatory drugs) work by inhibiting cyclooxygenase, abbreviated as COX, which is needed to produce prostaglandins. Prostaglandins are responsible for the inflammation and swelling that induce pain, as well as acting as a stimulant to platelet formation. NSAIDs are known also as COX-Inhibitors and are separated by classes. Cox-1, COX-2 recently, COX-3. COX-1 and COX-2 enzymes were discovered as recently as 1989! ?However, these COX-2 inhibitors do not decrease platelet aggregation or thromboxane synthesis while decreasing production of prostacyclin (an agent which decreases platelet aggregation). Therefore, concerns have been raised that individuals chronically treated with COX-2 inhibitors are at increased risk for platelet aggregation- associated adverse cardiovascular events? http://www.aaaai.org/aadmc/currentliterature/selectedarticles/2003archive/selective_cox2_inhibitors.html This page focuses on pain management of osteoarthritis but has some good information on alternative pain relievers. ?Can prolong the half-life of warfarin sodium, so careful monitoring of prothrombin time is recommended in patients taking warfarin sodium who subsequently begin higher-dose acetaminophen treatment. http://www3.aaos.org/research/imca/OAkneeContents/OA_knee_m5_4.htm About Diclofenac (Voltaren) ?Voltaren (Diclofenac sodium) is a nonsteroidal anti-inflammatory drug (NSAID) that is used to treat inflammation, mild to moderate pain, and fever. NSAID?s are called ?nonsteroidal? because they are not related to the steroid drugs (synthetic drugs that closely resemble cortisol, a hormone that is naturally produced by the adrenal glands). Steroids work by suppressing the immune system, whereas NSAID?s work mainly by preventing the formation of prostaglandins, hormone-like substances which trigger pain and inflammation.? ?The conventional, first generation NSAID?s like Voltaren etc. (Diclofenac sodium) work by inhibiting both COX-1 and COX-2 enzymes. By blocking COX-2 they are effective in relieving pain and inflammation, but by inhibiting COX-1 they often produce unacceptable gastrointestinal side effects including diarrhea, bloating, heartburn, upset stomach (dyspepsia) and ulcers. These first generation NSAID's show different potencies against COX-1 compared with COX-2. Some, like ketoprofen, are relatively COX-1 selective; others, like aspirin, ibuprofen and naproxen, are equally selective; and some like diclofenac are relatively COX-2 selective.? http://www.nlm.nih.gov/medlineplus/druginfo/medmaster/a699002.html http://www.vetmedpub.com/cp/pdf/symposium/nov_1.pdf This Ingenta site refers to an obstetrical study that showed Vioxx to have a smaller effect on platelet aggregation than diclofenac ?Conclusion: Besides having a smaller effect on platelet aggregation, one oral dose of rofecoxib 50 mg given before surgery provided postoperative analgesia similar to that given by three doses of diclofenac 50 mg and was associated with less use of anti-emetics and less surgical blood loss in gynaecological surgery compared with diclofenac.? http://www.ingenta.com/isis/searching/ExpandTOC/ingenta?issue=infobike://oup/bjaint/2004/00000092/00000004&index=11 ?There are controversial results regarding the influence of diclofenac on hemostasis? http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=411036 ?Truly specific COX-2 inhibitors, celecoxib ( Celebrex, Pharmacia corporation) , and Rofecoxib (Vioxx, Merck) are now commercially available, and others are currently being researched? http://www.arthritis.co.za/cox.html This Medline site recommends ?tell your doctor and pharmacist what prescription and nonprescription medications you are taking, especially other heart medications; antibiotics; aspirin and other non-steroidal antiiflammatory drugs such as ibuprofen (Advil, Motrin) and naproxen (Aleve, Naprosyn); cimetidine (Tagamet); medications for cancer, depression, diabetes, digestive problems, epilepsy, gout, high cholesterol, and thyroid problems; and vitamins. Many medications interfere with the effectiveness of warfarin. It is important that you tell your doctor every medication that you take, including nonprescription medications. Do not take any new medications without talking to your doctor.? http://www.nlm.nih.gov/medlineplus/druginfo/medmaster/a682277.html It would therefore seem prudent to take acetominophen (Tylenol), instead of diclofenac, for leg pain from DVT, or possibly aspirin, but only if the patient is NOT on coumadin. (I can?t see a DVT patient NOT taking an anti-coagulant!) Do NOT take aspirin AND coumadin. The patient?s physician is the best source of information for proper pain management in a DVT patient, as s/he is familiar with the patients entire medical history. ========================================================================= Question 2. Could increased platlet aggregation worsen or lead to a DVT condition? ========================================================================= Did know that the knifelets and forklets conglomerate while the platelets aggregate? ;-) (I couldn?t resist a bit of hospital humor!) The short answer to your question is yes. You want to avoid having platelets aggregate or clump in DVT patients, as this could precipitate clot formation. Aspirin, if the patient is NOT on anticoagulants, is effective in reducing the ?stickiness? of platelets. ?Platelets begin the formation of blood clots by clumping together (a process called aggregation). Platelet clumps are then strengthened and expanded by the action of clotting factors (coagulants) that result in the deposition of protein (fibrin) among the platelets? http://www.medicinenet.com/Heart_Attack/page3.htm As platelets pass through a vein with DVT, they adhere to the injured area. The platelets that collect then trigger a chain reaction; thrombin is produced, which produces fibrin strands, the strands clump together into a web. This web then entraps passing red blood cells and other platelets, and a clot is born! Vitamin C is thought to reduce platelet aggregation, while smoking and consuming sugar may increase platelet stickiness! http://www.docguide.com/news/content.nsf/news/8525697700573E1885256BC200721D3E ?Eating foods high in sugar increases the content of serotonin in platelets. It is known that platelets with increased quantities of serotonin are more likely to have stickiness. Therefore, it can be concluded that the use of large quantities of sugar in the diet would increase platelet stickiness and therefore increase the likelihood of having intravascular clotting. (Ref. Diabetes 40 (suppl. I):588A May, 1991)? http://www.ucheepines.org/blood_clotting.htm http://www-als.lbl.gov/als/science/sci_archive/69platelet.html You may be also be referring to the platelet aggregation test. A platelet aggregation test is a way to determine clotting and bleeding problems. Normal results are >60% of platelets aggregate with each agonist used for testing. http://www.mgh.harvard.edu/labmed/lab/coag/handbook/CO003900.htm ?There are many medications that can affect the results of the platelet aggregation test. The patient should discontinue as many as possible beforehand. Some of the drugs that can decrease platelet aggregation include aspirin, some antibiotics, beta blockers, dextran (Macrodex), alcohol, heparin (Lipo-Hepin), nonsteroidal anti-inflammatory drugs (NSAIDs), tricyclic antidepressants, and warfarin (Coumadin).? http://www.healthatoz.com/healthatoz/Atoz/ency/platelet_aggregation_test.html There is an animation on this page depicting the blood clotting process. Click onto the video called ?How a Blood Clot Forms? (Of course the others are informative too!) http://www.dvt.net/preventionCenter/animations.jsp?id=27 ==================================================================== Question 3. Could changes in prothrombin and and partial thromboplastin times lead to a worsening or occurance of the DVT condition? ==================================================================== Pro Time and PTT The protime (PT) and PTT (Partial thromboplastin time) results themselves have no bearing on DVT, but a change in the results of a PT can indicate the need for a coumadin dosage change. The PTT test is only useful while the patient is on IV heparin. Once a hospitalized patient comes home, the IV heparin is stopped, and oral coumadin begins. (Heparin is administered only via IV, as it is not stable in oral form) Pro times ARE useful in DVT patients. However, patients taking coumadin for DVT would be expected to have a longer PT than non-medicated patients, and this is desirable. The INR is the portion of the Pro time result that the doctor is interested in, as opposed to the results. An INR result of 2 to 3 is a target range for a patient on coumadin for DVT. If the patient is taking too much coumadin, the INR will be become elevated, indicating the need to decrease the amount of anti-coagulant medication If the INR gets too low, indicating that not enough coumadin is being taken, yes, the risk of aggravating DVT esists. The dose of anti-coagulant therapy is increased if this occurs. http://www.nlm.nih.gov/medlineplus/ency/article/000156.htm INR The INR (International Normailzed Ratio) was developed, I?m *guestimating*, about 10 years ago, for the purpose of standardizing PT results between labs. As each lab has its own methodology and normal ranges, a way to correlate results from different labs was needed. The INR is, simply put, a ratio derived from the patients PT results, the control results and an internationl standard factor. http://health.ucsd.edu/labref/P609.html http://www.newlinemedical.com/pro%20time%20table.html D-dimer Another helpful test for monitoring DVT is the D-dimer, sometimes called Fragment D-dimer or Fibrin degradation fragment, which is elevated in DVT patients. D-dimer indicates that there is a there is clotting and fibrinolysis (clot break down) process occurring in the circulatory system. The normal range, indicating no DVT or pulmonary empbolism, for D-dimer is < 0.41 g/mL http://www.labtestsonline.org/understanding/analytes/d_dimer/test.html http://www.medicalpost.com/mpcontent/article.jsp?content=/content/EXTRACT/RAWART/3734/47A.html http://www.pathology.vcu.edu/clinical/coag/ranges.html ?D-Dimer levels remain elevated in DVT for about 7 days. Patients presenting late in their course, after clot organization and adherence have occurred, may have low levels of D-dimer. Similarly, patients with isolated calf-vein DVT may have a small clot burden and low levels of D-dimer below the analytic cut-off value of the assay. This accounts for the reduced sensitivity of the D-dimer assay in the setting of confirmed DVT.? Emedicine http://www.emedicine.com/EMERG/topic122.htm MD Alert says about the D-dimer test o?Do not rely solely on a negative D-dimer test to exclude DVT when a patient has more than one of the characteristics listed above. Patients with more than one of these factors are considered to be at higher risk of DVT. For these higher-risk patients, the negative predictive value of a D-dimer test is only 89%. When D-dimer tests are negative in such patients, compression leg ultrasound tests should still be obtained to confirm the absence of DVT. oConfirm that your laboratory is using an appropriate D-dimer assay. The assays with the best negative predictive values for DVT are the SimpliRED and IL-Test. http://praxis.md/index.asp?page=alertsarchive&news_id=5693&alert=MD ==================================================================== Additional Reading: ==================================================================== An excellent description of the physiology and metabolic pathways of COX inhibitors. http://www.emedicine.com/med/topic3096.htm From DVT net, download several informative documents on DVT. http://www.dvt.net/preventionCenter/preventionGuides.jsp?id=23 http://www.weissortho.com/glossary/ http://www.spineuniverse.com/displayarticle.php/article2482.html http://www.healthinaging.org/public_education/pef/deep_venous_thrombosis.php This site has a good illustration of how NSAIDs work: http://elfstrom.com/arthritis/nsaids/actions.html I hope this is the information you were seeking! If any part of my answer is unclear, or if I have duplicated information you already had, please request an Answer Clarification, before rating. This will enable me to assist you further, if possible. Regards, crabcakes Search Terms DVT NSAIDs DVT Thrombolytics Diclofenac DVT Nasaids coumadin concurrently Platelet aggregation Diclofenac effect platelets Coagulation labs


  • Thank you for the stars! Regards, crabcakes


  • Good information. Thank you very much.







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