Warning about Tegretol® Suspension
(carbamazepine USP)
In April, Dr. Jean-Paul Castaigne (MD; Vice President, Medical & DRA, Novartis Pharmaceuticals Canada Inc.) distributed a letter to physicians, pharmacists and other health care workers, warning that "Tegretol® (carbamazepine USP) Suspension should not be administered simultaneously with other liquid medicinal agents or diluents."
"There has been a report of a patient in the U.S. who passed an orange rubbery mass in his stool the day after ingesting Tegretol® Suspension immediately followed by Thorazine (chlorpromazine) solution. Subsequent testing has shown that mixing Tegretol® Suspension and chlorpromazine solution (both generic and brand name) as well as Tegretol® Suspension and liquid Mellaril (thioridiazine HCL USP) results in the precipitation of a rubbery orange mass. It is not known if the formation of this precipitate results in decreased bioavailability of Tegretol® or of either of the other two medications tested."
"The extent to which this interaction occurs, if at all, with other liquid medications is not known."
"Systematic testing is underway to determine the cause and nature of this interaction. We will communicate additional information when it becomes available.... Please inform your patients...."
For medical information about any Novartis product, contact
Novartis Pharmaceuticals Canada Inc.
385 Bouchard Boulevard
Dorval, Québec H9R 4P5
1-800-363-8883
514-631-6775
514-639-7054 fax
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