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? 

Affects the metabolism:

• Phenobarbitone
• Phenytoin
• Carbamazepine
• Oxcarbazepine
• Topiramate

Oral contraceptives’ serum concentration may be decreased by anti-epileptic drugs. This can cause unplanned pregnancies. Higher doses of contraceptives is then needed and additional contraceptive methods should be used if breakthrough bleeding occurs.

Safe to use:

• Valproate
• Lamotrigine
• Gabapentin
• Levetiracetam
• Vigabatrin

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

Yes. Oral contraceptives decreases lamotrigine and valproate serum levels.

How does age affect the kinetics of these drugs (from neonates to old age)?

Neonates: Slow metabolism of drugs

Children: Metabolism is faster than adults.

Adults: Metabolism is slower than children

Geriatrics: Slow metabolism of drugs.

In which cases is plasma blood level monitoring indicated?

• A change in dosage is made
• Finding a suitable maintenance dose
• To monitor any side-effects
• Neonates
• Geriatrics
• During pregnancy
• When seizures occur
• Drug interactions.