II. Associated Conditions

  1. Catamenial Seizure
    1. Occurs in up to 50% of women with Epilepsy
    2. Seizure related to Menstrual Cycle
      1. Onset of Menses due to Progesterone withdrawal
      2. Mid-cycle at Ovulation due to Estrogen surge
  2. Polycystic Ovary Disease
    1. Occurs in up to 40% of women with Epilepsy
    2. Subset related to Valproate
      1. Improves with medication change

III. Pearls

  1. Women should not get pregnant while on most Seizure medications
    1. Antiepiletic agents significantly increase the risk of congenital malformation

IV. Management: Contraceptive Selection in Epilepsy

  1. Precautions
    1. Highly effective Contraception is critical
      1. See Pearls above regarding risk of congenital malformation
    2. Many antiepileptic medications decrease efficacy of Oral Contraceptives (see Drug Interactions)
  2. Consider non-Hormonal Contraception
  3. Avoid Oral Contraceptives with antiepileptics that induce CYP P450
    1. Agents listed below under Drug Interactions render OCPs less effective
      1. Oral Contraceptive failure rate with these agents >6%
    2. Norplant (not available in United States) also less effective with these agents
    3. High-dose Estrogen may be needed to suppress Ovulation
      1. Use 50 ug Estrogen pill if OCP used for Contraception
  4. Avoid Oral Contraceptives with Lamotrigine (Lamictal)
    1. Lamotrigine clearance is increased in the presence of Estrogen containing Oral Contraceptives
  5. Avoid Depo Provera if possible
    1. Both Depo Provera and many anti-epileptics increase Osteoporosis risk
  6. Intrauterine Devices
    1. Copper-T IUD may be preferred
    2. Mirena IUD (Levonorgestrel) has higher failure rate (1.1 pregnancies per 100 woman-years)

V. Drug Interactions: Oral Contraceptives (OCP)

  1. Antiepileptics that induce P450 system (avoid with OCP)
    1. Carbamazepine (Tegretol)
    2. Ethosuximide (Zarontin)
    3. Felbamate
    4. Phenobarbital
    5. Phenytoin (Dilantin)
    6. Primidone (Mysoline)
    7. Oxcarbazepine (Trileptal)
    8. Topiramate (Topamax)
  2. Antiepileptics that do not affect OCP efficacy
    1. Gabapentin (Neurontin)
    2. Levetiracetam (Keppra)
    3. Lamotrigine (Lamictal)
    4. Tiagabine (Gabitril)
    5. Valproate (Depakote)
    6. Zonisamide (Zonegran)

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