Optiflex-G

There are 0 contraindications.

There are 0 severe interactions.

There are 1 moderate interactions. The clinician should assess the patient’s characteristics and take action as needed. Actions required for moderate interactions include, but are not limited to, discontinuing one or both agents, adjusting dosage, altering administration.

Drug Interaction	Drug Names
Coumarin Anticoagulants/Glucosamine and-or Chondroitin SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: The exact mechanism is unknown, but may be the result of additive or synergistic effects on coagulation. Glucosamine is a component of heparin(1) and chondroitin is a component of danaparoid.(2) Glucosamine has been shown not to inhibit CYP2C9,(3) thus inhibition of warfarin metabolism is thought to be unlikely. CLINICAL EFFECTS: Concurrent use of glucosamine-chondroitin may result in increased effects on coagulation, including elevated International Normalized Ratio (INR) and bleeding. PREDISPOSING FACTORS: The risk for bleeding episodes may be greater in patients with disease-associated factors (e.g. thrombocytopenia). Drug associated risk factors include concurrent use of multiple drugs which inhibit anticoagulant/antiplatelet metabolism and/or have an inherent risk for bleeding (e.g. NSAIDs). PATIENT MANAGEMENT: Use caution with adding or discontinuing glucosamine-chondroitin to warfarin therapy. Monitor patients receiving concurrent therapy closely for elevated INR and signs of bleeding. Patients who discontinue glucosamine-chondroitin may need their warfarin dosage adjusted to maintain therapeutic INRs. If concurrent therapy is warranted, monitor patients receiving concurrent therapy for signs of blood loss, including decreased hemoglobin, hematocrit, fecal occult blood, and/or decreased blood pressure and promptly evaluate patients with any symptoms. When applicable, perform agent-specific laboratory test (e.g. INR, aPTT) to monitor efficacy and safety of anticoagulation. Discontinue anticoagulation in patients with active pathologic bleeding. Instruct patients to report any signs and symptoms of bleeding, such as unusual bleeding from the gums or nose; unusual bruising; red or black, tarry stools; red, pink or dark brown urine; acute abdominal or joint pain and/or swelling. The time of highest risk for a coumarin-type drug interaction is when the precipitant drug is initiated or discontinued. Contact the prescriber before initiating, altering the dose or discontinuing either drug. DISCUSSION: There have been numerous reports of increased INR following the addition of glucosamine, glucosamine-chondroitin, or chondroitin alone to warfarin therapy, including 20 from the United States Food Drug Administration (US FDA), 22 from the World Health Organization (WHO), 3 from the Australian Therapeutic Goods Association (TGA), and 2 published reports. INR values typically increased between two and 20 days after the addition of glucosamine and/or chondroitin to warfarin therapy. In most cases, patients were asymptomatic; however, there were at least two reports of bleeding.(4-8) There has also been one report involving glucosamine and acenocoumarol.(9)	DICUMAROL, JANTOVEN, WARFARIN SODIUM

Drug Interaction

Drug Names

Coumarin Anticoagulants/Glucosamine and-or Chondroitin

SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.

MECHANISM OF ACTION: The exact mechanism is unknown, but may be the result of additive or synergistic effects on coagulation. Glucosamine is a component of heparin(1) and chondroitin is a component of danaparoid.(2) Glucosamine has been shown not to inhibit CYP2C9,(3) thus inhibition of warfarin metabolism is thought to be unlikely.

CLINICAL EFFECTS: Concurrent use of glucosamine-chondroitin may result in increased effects on coagulation, including elevated International Normalized Ratio (INR) and bleeding.

PREDISPOSING FACTORS: The risk for bleeding episodes may be greater in patients with disease-associated factors (e.g. thrombocytopenia). Drug associated risk factors include concurrent use of multiple drugs which inhibit anticoagulant/antiplatelet metabolism and/or have an inherent risk for bleeding (e.g. NSAIDs).

PATIENT MANAGEMENT: Use caution with adding or discontinuing glucosamine-chondroitin to warfarin therapy. Monitor patients receiving concurrent therapy closely for elevated INR and signs of bleeding. Patients who discontinue glucosamine-chondroitin may need their warfarin dosage adjusted to maintain therapeutic INRs.

If concurrent therapy is warranted, monitor patients receiving concurrent therapy for signs of blood loss, including decreased hemoglobin, hematocrit, fecal occult blood, and/or decreased blood pressure and promptly evaluate patients with any symptoms. When applicable, perform agent-specific laboratory test (e.g. INR, aPTT) to monitor efficacy and safety of anticoagulation. Discontinue anticoagulation in patients with active pathologic bleeding.

Instruct patients to report any signs and symptoms of bleeding, such as unusual bleeding from the gums or nose; unusual bruising; red or black, tarry stools; red, pink or dark brown urine; acute abdominal or joint pain and/or swelling. The time of highest risk for a coumarin-type drug interaction is when the precipitant drug is initiated or discontinued. Contact the prescriber before initiating, altering the dose or discontinuing either drug.

DISCUSSION: There have been numerous reports of increased INR following the addition of glucosamine, glucosamine-chondroitin, or chondroitin alone to warfarin therapy, including 20 from the United States Food Drug Administration (US FDA), 22 from the World Health Organization (WHO), 3 from the Australian Therapeutic Goods Association (TGA), and 2 published reports. INR values typically increased between two and 20 days after the addition of glucosamine and/or chondroitin to warfarin therapy. In most cases, patients were asymptomatic; however, there were at least two reports of bleeding.(4-8) There has also been one report involving glucosamine and acenocoumarol.(9)

DICUMAROL, JANTOVEN, WARFARIN SODIUM

OPTIFLEX-G (glucosamine sulfate)