Gabapentin and Valproic acid interaction

Children under the age of two years are at a considerably increased risk of developing fatal hepatotoxicity, especially those on multiple anticonvulsants, those with congenital metabolic disorders, those with severe seizure disorders accompanied by mental retardation, and those with organic brain disease.

In patients over two years of age who are clinically suspected of having a hereditary mitochondrial disease, valproic acid oral solution should only be used after other anticonvulsants have failed.

Patients on multiple anticonvulsants, children, those with congenital metabolic disorders, those with severe seizure disorders accompanied by mental retardation, and those with organic brain disease may be at particular risk.

Patients receiving valproate and ethosuximide, especially along with other anticonvulsants, should be monitored for alterations in serum concentrations of both drugs.

Published epidemiological studies have indicated that children exposed to valproate in utero have lower cognitive test scores than children exposed in utero to either another antiepileptic drug or to no antiepileptic drugs.

When the decision is made to co-prescribe NEURONTIN with another CNS depressant, particularly an opioid, or to prescribe NEURONTIN to patients with underlying respiratory impairment, monitor patients for symptoms of respiratory depression and sedation, and consider initiating NEURONTIN at a low dose.

Valproic Acid The mean steady-state trough serum valproic acid concentrations prior to and during concomitant gabapentin administration (400 mg three times a day; N=17) were not different and neither were gabapentin pharmacokinetic parameters affected by valproic acid.

Patients should be carefully observed for signs of central nervous system (CNS) depression, such as somnolence and sedation, when NEURONTIN is used with other drugs with sedative properties because of potential synergy.

Other Antiepileptic Drugs Gabapentin is not appreciably metabolized nor does it interfere with the metabolism of commonly coadministered antiepileptic drugs [see Clinical Pharmacology (12.3) ] .

Drug/Laboratory Test Interactions Because false positive readings were reported with the Ames N-Multistix SG ® dipstick test for urinary protein when gabapentin was added to other antiepileptic drugs, the more specific sulfosalicylic acid precipitation procedure is recommended to determine the presence of urine protein.