• Which of the anti-epileptic drugs affect the metabolism of the Pill (oral contraceptive) and what are the implications of this? Which drugs are safe to use in combination with the Pill? 

• Phenobarbitone
• Phenytoin
• Carbamazepine
• Oxcarbazepine
• Topiramate
•  Perampenel (decreases levonorgestrel-containing contraceptives).

All these medication decreases the pill effectiveness. This may cause unexpected pregnancies and teratogenic effects.

Drugs that are safe to use with the Pill:

• • Valproate
  • Lamotrogine
  • Gabapentin
  • Leviteracetam
  • Vigabatrin.

• Can oral contraceptives also affect the effectivity of the anti-epileptic drugs?

Yes, oral contraceptives decrease Lamotrigine and Valproate serum levels. This can result in seizures.

• How does age affect the kinetics of these drugs (from neonates to old age)?
  • Neonates have a slow metabolism, so must receive lower dosages.
  • Babies and children have a faster metabolism than adults, so they receive higher dosages.
  • Geriatric patients have a slow metabolism and decreased renal function, so they should receive lower dosages.

• In which cases is plasma blood level monitoring indicated?

Plasma blood level monitoring is required, where protein binding takes place. Anti-epileptic drugs that does affect protein binding:

• • Gabapentin
  • Ethosuximide
  • Topiramate.

Certain diseases which may affect protein binding and require plasma blood level monitoring:

• • Kidney failure
  • Liver diseases
  • Hypoalbuminemia

Other conditions/instances that require plasma blood level monitoring

 : burns, pregnancy, malnutrition, age

Reference list:

Brand, L.Prof.  2021.  Study Unit 4:Anti-Epileptic Drugs.  Unpublished lecture notes on efundi, FKLG 312.  Potchefstroom: NWU.  [PowerPoint presentation].