WHO Pharmaceuticals Newsletter 1998, No. 03&04
(1998; 18 pages)
Table of Contents
Close this folderRegulatory actions
View the documentAluminium in total parenteral nutrition - labelling requirements & warning
View the documentAstemizole - warning concerning cardiovascular adverse events
View the documentBromfenac - warning label: liver damage
View the documentCarbamazepine - warning concerning precipitation
View the documentChlormezanone - withdrawn
View the documentCounterfeit drugs - warning to the public
View the documentDietary supplement "Sleeping Buddha" - warning concerning estazolam content
View the documentFenfluramine - withdrawn
View the documentHuman dura mater (freeze-dried) - restrictive measures
View the documentIsotretinoin - psychiatric adverse effects
View the documentPyrithione zinc (Skin-CapR) - withdrawn
View the documentSertindole - approval application withdrawn
View the documentTerfenadine - additional drug interactions
View the documentTerfenadine - withdrawn following approval of fexofenadine
Open this folder and view contentsDrug surveillance
Open this folder and view contentsNew developments
View the documentRecent approvals
Open this folder and view contentsMedical devices
Open this folder and view contentsGeneral information
Open this folder and view contentsVeterinary medicine

Carbamazepine - warning concerning precipitation

Novartis. The manufacturer of carbamazepine has alerted health professionals that carbamazepine suspension (TegretolR Suspension: Novartis) should not be administered simultaneously with other liquid medicinal agents or diluents because of a risk of precipitation and the possibility of decreased bioavailability.

The company has submitted to the US Food and Drug Administration a report of a patient who passed an orange rubbery mass in his stool the day after ingesting TegretolR Suspension immediately followed by chlorpromazine (ThorazineR) solution. Subsequent testing has shown that mixing TegretolR Suspension and chlorpromazine solution (both generic and brand name) as well as TegretolR Suspension and liquid MellarilR (thioridazine) results in the precipitation of a rubbery orange mass. It is not known if the formation of this precipitate results in decreased bioavailability of carbamazepine 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 under way to determine the cause and nature of this interaction.

The package insert has been modified to include this information in the relevant sections.

Reference: "Dear Doctor" letter, Novartis Pharmaceutical Corporation, East Hanover, USA, March 1998.

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