COMPLEMENTARY AND ALTERNATIVE MEDICATIONS

Brief History. S.G. is a 75-year-old man who began experiencing osteoarthritic changes in his right knee when he was in his 50s. This condition worsened progressively, necessitating a total knee arthroplasty, which was performed 2 years ago. The initial knee replacement became unstable and was recently revised surgically to decrease pain and to promote better function. While in the hospital for this revision, the patient developed a deep vein thrombosis and was placed on heparin followed by warfarin (Coumadin) to control excessive coagulation. He continued taking the warfarin when he was discharged, and a physical therapist began providing home care on a regular basis. During the initial visit, the therapist asked the patient if he was taking any additional medications. He replied that he had recently started taking a nonprescription product that contained St. John’s wort. Apparently, this patient had become very discouraged and despondent because of problems with his knee replacement and his inability to resume his hobbies and social activities, such as playing golf and gardening. A friend had recommended he take St. John’s wort as an alternative way to improve his mood while recovering from the most recent knee surgery Problem/Infl uence of Medication. St. John’s wort can cause enzyme induction, which results in an increase in the liver’s ability to metabolize other medications, including warfarin. This process could result in the warfarin being metabolized too rapidly and therefore failing to reach therapeutic levels. Lack of adequate anticoagulant effects would place the patient at increased risk for subsequent thrombosis and pulmonary embolism. Questions to Consider

1. What should the therapist do to resolve concerns about the interaction of St. John’s wort and warfarin?

2. What additional monitoring might be helpful to assess whether warfarin is still effective?