• DOI:10.1111/j.1528-1167.2005.00605.x
• Corpus ID: 7696039

Serum Valproate Levels with Oral Contraceptive Use

@article{Herzog2005SerumVL,
  title={Serum Valproate Levels with Oral Contraceptive Use},
  author={Andrew G Herzog and Erin L. Farina and A S Blum},
  journal={Epilepsia},
  year={2005},
  volume={46}
}

• A. Herzog, E. L. Farina, A. Blum
• Published 1 June 2005
• Medicine
• Epilepsia

It has long been recognized that the use of the older enzyme-inducing antiepileptic drugs (AEDs), such as barbiturates, phenytoin (PHT) and carbamazepine (CBZ), is associated with higher failure rates of oral contraceptive pills (OCPs), likely because of the induction of the catabolism and binding of reproductive steroids (1). A newer enzyme-inducing AED, topiramate (TPM), also has been shown to reduce serum OCP steroid levels at daily dosages of ≥200 mg (2). Clinically significant interactions between OCPs and enzyme-neutral [e.g., lamotrigine (LTG), gabapentin (GBP)] and inhibitory [e.g., valproate (VPA)] drugs have not been considered to be of concern (1) until some recent reports suggested that the use of OCPs by women who take LTG is associated with statistically significant and substantial (>50%) reductions in the serum levels of LTG (3,4). In one of these reports (3), the introduction of OCPs was associated with increased seizure frequency or recurrence of seizures in most of the cases. The possibility of a similar relation between VPA and OCP use is raised by the following case.