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 anticonvulsants such as carbamazepine, phenobarbital, phenytoin, and primidone may speed up how quickly your body processes nifedipine, nimodipine or nisoldipine.
What might happen:
If you are taking carbamazepine, phenobarbital, phenytoin, or primidone, the amount of nifedipine, nimodipine or nisoldipine in your blood may decrease and it may not work as well, or it may not work at all.
What you should do about this interaction:
Let your healthcare professionals (e.g. doctor or pharmacist) know right away that you are taking these medicines together. Your doctor may want to adjust the dose or change your medicine.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.Adalat (nifedipine) US prescribing information. Bayer Healthcare Pharmaceuticals Inc. February, 2011.
2.Nimotop (nimodipine) UK summary of product characteristics. Bayer plc April 23, 2008.
3.Tartara A, Galimberti CA, Manni R, Parietti L, Zucca C, Baasch H, Caresia L, Muck W, Barzaghi N, Gatti G, et al. Differential effects of valproic acid and enzyme-inducing anticonvulsants on nimodipine pharmacokinetics in epileptic patients. Br J Clin Pharmacol 1991 Sep;32(3):335-40.
4.This information is based on or an extract from the UW Metabolism and Transport Drug Interaction Database (DIDB) Platform, Copyright University of Washington 1999-2014..
5.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.
6.Sular (nisoldipine) US prescribing information. Shionogi, Inc. December, 2012.
7.Michelucci R, Cipolla G, Passarelli D, Gatti G, Ochan M, Heinig R, Tassinari CA, Perucca E. Reduced plasma nisoldipine concentrations in phenytoin-treated patients with epilepsy. Epilepsia 1996 Nov; 37(11):1107-10.