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carbamazepine oral

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.


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.
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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.
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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.
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