Anti-coagulation medications & precautions

1. What are the broad categories for the prescription of heparin and warfarin, both as prophylaxis and for acute management? 
   
   Acute episode of DVT, PE, or a history or of DVT, PE.  Also for cardiovascular disease, cerebrovascular disease, arrhythmias (atrial fibrillation), mitral valve prolapse.
   
   
2. After major surgery, e.g. hip arthroplasty, describe the typical anticoagulant regimen
   • Inpatient: commonly started on IV heparin during the procedure, e.g. bypass surgery (rapid acting)
   • Inpatient: prior to hospital discharge begin subcutaneous enozaparin (Lovenox), which is a low molecular weight heparin (LMWH) which is has a lower risk of adverse events (hemorrhage). It has a more predictable response and does not require routine monitoring of prothrombin time (PT), international normalized ration (INR) and partial prothrombin time (PPT).
   • The subcutaneous route is more practical for home or outpatient administration. It serves as a bridge to long term oral medication use, i.e. warfarin, which takes longer to load.
   • Eventually the patient is transitioned to warfarin (Coumadin), oral. Warfarin has a narrow therapeutic index (benefit/risk ratio), so it requires frequent monitoring of blood levels so that the lowest therapeutic dose is maintained. Warfarin can be potentiated or inhibited by other drugs. It can be inhibited by some foods.
     
     
3. What are additional precautions the therapist should take when the patient is using an anticoagualant like warfarin?
   • Coumadin (warfarin) is monitored regularly to see if prothrombin time (PT), international normalized ration (INR) and partial prothrombin time (PPT) are prolonged.  
   • Bruising that can be explained by unusual tissue trauma is not likely to be a problem, but if bruising occurs without the patient being aware of the cause, or if bruises are extensive, the physician should be contacted.  In addition, the therapist should consider the possibility of physical abuse when bruises are present.   How might you distinguish bruises caused by anticoagulant therapy from bruises received from trauma, either accidental or from abuse? A circumferential bruise on the forearm, for example, would be suspect.
   • Warfarin increases the risk of internal hemorrhage that could present insidiously as anemia, and possibly result in vertigo and balance disturbances. 
   • Warfarin can have GI hemorrhage side effects.  REMEMBER, women are more likely to report gastric discomfort as a symptom of angina than are men.  Is your patient on a med for gastritis?  Is so, that can mask this effect.
     Consider how to go about muscle testing if bruises are easily produced. 
   • REHAB CONSIDERATIONS:
     • wound care and debridement methods need to take into account the increased bleeding risk
     • precaution with forceful chest percussion
     • precaution with deep tissue massage
       
       
4. Anticoagulants can interact with other drugs or food. List interactions that should be monitored.
   • The patient is advised to avoid OTC NSAIDs unless consulting the prescribing physician.  These drugs will potentiate the anticoagulation properties resulting in an added risk of GI hemorrhage.
   • Persons on Warfarin should eat moderately or minimize the consumption of green leafy vegetables, which are high in Vitamin K, a nutrient essential to the production of Prothrombin for clotting.  Vitamin K counteracts the effect of Warfarin.  * Don’t get Vitamin K confused with Potassium Supplements “K”.
   • Alcohol (ETOH) potentiates the effect of Warfarin. 
     
     
5. Once anticoagulation therapy for an acute DVT has been initiated, describe current best practice regarding early ambulation.
   • Early ambulation with lower extremity compression garments is begun after either 24 hours of bedrest or after up to 72 hours of bedrest, depending on the physician and the guidelines at the institution. If the patient has adequate cardiac reserve, there is not an increased risk of pulmonary embolism. Walking contributes to more rapid resolution of pain and swelling.
     

Resources:

• Ciccone, C. (2007). Pharmacology in Rehabilitation. (4th ed.). Philadelphia: F. A. Davis Company. Chapter 25.
• Watchie, J. (2010). Cardiovascular and Pulmonary Physical Therapy. (2nd ed.). Philadelphia: Saunders-Elsevier. p.199-202, p.124-125.
• MU PT - Pharmacy Tool Kit: CV & Pulm Meds (Prost)