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Epitol

Interactions

Valproic Acid/Carbamazepine

This information is generalized and not intended as specific medical advice. Consult your healthcare professional before taking or discontinuing any drug or commencing any course of treatment.

Medical warning:

Moderate. These medicines may cause some risk when taken together. Contact your healthcare professional (e.g. doctor or pharmacist) for more information.

How the interaction occurs:

When these two medicines are taken together, your body may process carbamazepine more slowly. You may also process valproic acid more quickly.

What might happen:

Your blood levels of carbamazepine may increase and cause toxic effects. Your blood levels of valproic acid may decrease and cause seizures.

What you should do about this interaction:

If you experience confusion, fever, tremors, mental or mood changes, weakness, seizures, or other symptoms, contact your doctor. It may be necessary to change your dose of one or both medicines. Your doctor may also want to measure your blood levels of these medicines more often.Your healthcare professionals (e.g. doctor or pharmacist) 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.

References:

1.Adams DJ, Luders H, Pippenger C. Sodium valproate in the treatment of intractable seizure disorders: a clinical and electroencephalographic study. Neurology 1978 Feb;28(2):152-7.

2.Wilder BJ, Willmore LJ, Bruni J, Villarreal HJ. Valproic acid: interaction with other anticonvulsant drugs. Neurology 1978 Sep;28(9 Pt 1):892-6.

3.Schapel GJ, Beran RG, Doecke CJ, O'Reilly WJ, Reece PA, Rischbieth RH, Sansom LN, Stanley PE. Pharmacokinetics of sodium valproate in epileptic patients: prediction of maintenance dosage by single-dose study. Eur J Clin Pharmacol 1980 Jan;17(1):71-7.

4.Reunanen MI, Luoma P, Myllyla VV, Hokkanen E. Low serum valproic acid concentrations in epileptic patients on combination therapy. Curr Ther Res 1980 Sep;28(3):456-62.

5.Hoffmann F, von Unruh GE, Jancik BC. Valproic acid disposition in epileptic patients during combined antiepileptic maintenance therapy. Eur J Clin Pharmacol 1981;19(5):383-5.

6.Brodie MJ, Forrest G, Rapeport WG. Carbamazepine 10, 11 epoxide concentrations in epileptics on carbamazepine alone and in combination with other anticonvulsants. Br J Clin Pharmacol 1983 Dec;16(6):747-9.

7.Levy RH, Moreland TA, Morselli PL, Guyot M, Brachet-Liermain A, Loiseau P. Carbamazepine/valproic acid interaction in man and rhesus monkey. Epilepsia 1984 Jun;25(3):338-45.

8.Jann MW, Fidone GS, Israel MK, Bonadero P. Increased valproate serum concentrations upon carbamazepine cessation. Epilepsia 1988 Sep-Oct; 29(5):578-81.

9.Robbins DK, Wedlund PJ, Kuhn R, Baumann RJ, Levy RH, Chang SL. Inhibition of epoxide hydrolase by valproic acid in epileptic patients receiving carbamazepine. Br J Clin Pharmacol 1990 Jun;29(6):759-62.

10.Ramsay RE, McManus DQ, Guterman A, Briggle TV, Vazquez D, Perchalski R, Yost RA, Wong P. Carbamazepine metabolism in humans: effect of concurrent anticonvulsant therapy. Ther Drug Monit 1990 May;12(3):235-41.

11.Johnsen SD, Johns DW. Carbamazepine epoxide toxicity in children receiving carbamazepine and valproate. Ann Neurol 1991;30(3):491.

12.Ketter TA, Pazzaglia PJ, Post RM. Synergy of carbamazepine and valproic acid in affective illness: case report and review of the literature. J Clin Psychopharmacol 1992 Aug;12(4):276-81.

Selected from data included with permission and copyrighted by First Databank, Inc. This copyrighted material has been downloaded from a licensed data provider and is not for distribution, expect as may be authorized by the applicable terms of use.

CONDITIONS OF USE: The information in this database is intended to supplement, not substitute for, the expertise and judgment of healthcare professionals. The information is not intended to cover all possible uses, directions, precautions, drug interactions or adverse effects, nor should it be construed to indicate that use of a particular drug is safe, appropriate or effective for you or anyone else. A healthcare professional should be consulted before taking any drug, changing any diet or commencing or discontinuing any course of treatment.

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