Which of the AED affect the metabolism of the pill (contraceptives)? What are the implications? Which drugs are safe to use in combination with the pill?

Drugs that affect the pill’s metabolism are:

• Phenobarbitone
• Phenytoin
• Carbamazepine
• Oxcarbazepine
• Topiramate

All of the drugs mentioned above decrease the pill’s effectiveness and could lead to the patient becoming pregnant whilst using contraceptives

Drugs that are safe to use in combination with the pill:

• Valproate
• Lamotrigine
• Gabapentin
• Levetiracetam
• Vigabatrin

Can the pill interfere with the effectiveness of the AED?

Yes. Oral contraceptives can decrease the serum levels of drugs such as Lamotrigine or Valproate, which could increase the patient’s risk for seizures

How does age affect the kinetics of these drugs?

Due to your geriatric patients having a decrease in renal function, it means they have decreased clearance of these drugs. They are therefore an increased risk for developing CNS toxicity

Neonates who also have a low renal function will need to receive small doses to prevent toxicity

When is plasma level monitoring necessary?

• When Lamotrigine and Valproate are given in combination. This combination can be fatal
• Patients who have decreased liver function