Isosulfan Blue

Clinical summary

Indications and usage 1 INDICATIONS AND USAGE Isosulfan blue injection 1% upon subcutaneous administration, delineates the lymphatic vessels draining the region of injection. It is an adjunct to lymphography in: primary and secondary lymphedema of the extremities; chyluria, chylous ascites or chylothorax; lymph node involvement by primary or secondary neoplasm; lymph node response to therapeutic modalities (1.1). 1.1 Lymphatic Vessel Delineation Isosulfan blue injection 1% upon subcutaneous administration, delineates lymphatic vessels draining the region of injection. It is an adjunct to lymphography in: primary and secondary lymphedema of the extremities; chyluria, chylous ascites or chylothorax; lymph node involvement by primary or secondary neoplasm; and lymph node response to therapeutic modalities. Dosage and administration 2 DOSAGE AND ADMINISTRATION Isosulfan blue injection 1% is to be administered subcutaneously, one-half (1/2) mL into three (3) interdigital spaces of each extremity per study. A maximum dose of 3 mL (30 mg) isosulfan blue is, therefore, injected (2.1). 2.1 Subcutaneous administration Isosulfan blue injection 1% is to be administered subcutaneously, one-half (1/2) mL into three (3) interdigital spaces of each extremity per study. A maximum dose of 3 mL (30 mg) isosulfan blue is, therefore, injected. Warnings and cautions 5 WARNINGS AND PRECAUTIONS Life-threatening anaphylactic reactions have occurred after isosulfan blue 1% administration. Monitor patients closely for at least 60 minutes after administration of isosulfan blue 1% (5.1). The admixture of isosulfan blue 1% with local anesthetics results in an immediate precipitation of 4 to 9% drug complex. Use a separate syringe for anesthetics (5.2). Isosulfan blue 1% interferes with measurements in peripheral blood pulse oximetry. Arterial blood gas analysis may be needed (5.3). 5.1 Hypersensitivity Reactions Life-threatening anaphylactic reactions (respiratory distress, shock, angioedema) have occurred after isosulfan blue 1% administration. Reactions are more likely to occur in patients with a history of bronchial asthma, allergies, drug reactions or previous reactions to triphenylmethane dyes. Monitor patients closely for at least 60 minutes after administration of isosulfan blue 1%. Trained personnel should be available to administer emergency care including resuscitation. 5.2 Precipitation of Isosulfan Blue 1% by Lidocaine The admixture of isosulfan blue 1% (with local anesthetics (i.e. lidocaine)) in the same syringe results in an immediate precipitation of 4 to 9% drug complex. Use a separate syringe to administer a local anesthetic. 5.3 Interference with Oxygen Saturation and Methemoglobin Measurements Isosulfan blue 1% interferes with measurements of oxygen saturation in peripheral blood by pulse oximetry and can cause falsely low readings. The interference effect is maximal at 30 minutes and minimal generally by four hours after administration. Arterial blood gas analysis may be needed to verify decreased arterial partial pressure of oxygen. Isosulfan blue 1% may also cause falsely elevated readings of methemoglobin by arterial blood gas analyzer. Therefore, co-oximetry may be needed to verify methemoglobin level. Drug interactions 7 DRUG INTERACTIONS No drug interactions have been identified with isosulfan blue 1%. No drug interactions have been identified for isosulfan blue 1% (7).