Switching Medicines
Most switches of seizure medicines require a period of overlap. The new drug usually cannot be added in full protective dose until a build-up schedule allows a person's system to become used to the drug. Sudden discontinuation of an old drug can lead to withdrawal seizures. A switch of seizure medication therefore comprises a few potentially unpleasant weeks, during which a person is on more medication, and subject to withdrawal symptoms.
A few exceptions exist for which sudden changes are reasonable, for example, Trileptal in place of Tegretol. If a medication is causing an allergy or other severe side effects, then sudden discontinuation may be the only good alternative. Changes of medicine regimens are complicated. The patient and family should have a written schedule detailing changes day-by-day or week-by-week. Typical change regimens decrease the old pills and increase the new pills every 3, 7, 14, or 30 days. The rate of switch will be individualized according to the severity of seizures, side effects and the properties of the drugs being changed.
Phone access to the treating physician or nurse is very useful during seizure medication changes, since reaction of the individual to a new medication is not entirely predictable.