Severe. These medicines may interact and cause very harmful effects and are usually not taken together. Contact your healthcare professional (e.g. doctor or pharmacist) for more information.
How the interaction occurs:
Some medicines may slow down how quickly your liver processes conivaptan and tolvaptan.
What might happen:
The amount of conivaptan or tolvaptan in your body may build up and cause more side effects than normal.
What you should do about this interaction:
Let your healthcare professional (e.g. doctor or pharmacist) know right away that you are taking these two medications together.Contact your healthcare professional right away if you begin feeling dizzy, drowsy, or confused; are more thirsty than usual; have trouble speaking or swallowing; or have any mood changes, trouble controlling body movements, weakness in the arms or legs, or seizures.Your healthcare professionals may already be aware of this interaction and may be monitoring you for it. Do not start, stop, or change the dosage of any medicine before checking with them first.
1.Vaprisol (conivaptan hydrochloride) US prescribing information. Astellas Pharma US, Inc. February, 2012.
2.Samsca (tolvaptan) US prescribing information. Otsuka Pharmaceutical Co., Ltd. February, 2014.
3.Samsca (tolvaptan) US prescribing information. Otsuka Pharmaceutical Co., Ltd. November, 2012.
4.US Food and Drug Administration (FDA). Drug Development and Drug Interactions: Table of Substrates, Inhibitors and Inducers. Available at: http://www.fda.gov/Drugs/DevelopmentApprovalProcess/DevelopmentResources/D rugInteractionsLabeling/ucm093664.htm. Updated 08/05/2011.