Valproic acid carnitine deficiency

A. Valproic acid is a low-molecular-weight (144.21), branched-chain carboxylic acid (pKg = 4.8) that increases levels of the inhibitory neurotransmitter gamma-aminobutyric acid (GABA) and prolongs the recovery of inactivated sodium channels. These properties may be responsible tor its action as a general central nervous system depressant. Valproic acid also alters amino acid and fatty acid metabolism with dismption of the urea cycle, and can cause hepatotoxicity, metabolic perturbations, cerebral edema, and bone marrow depression. Some of these effects may be associated with carnitine deficiency. 

We conclude that C8-camitine levels measured by MS-MS, are very useful to monitor the metabolic status in patients with MCAD deficiency. This marker will allow determining the best dietary treatment and fasting tolerance for these patients. This will probably be true as long as normal levels of free carnitine are maintained and valproic acid, which can increase C8-camitine levels and is contraindicated in patients with MCAD deficiency, is not given. Our results also highlight the importance of carefully recording the hours of fasting when values of AC are measured in patients with fatty acid oxidation disorders. 

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