Dilantin is an anti-convulsant or anti-seizure medication that has been used to treat epilepsy since 1938. It works on the cerebral cortex to reduce the strength and speed of electrical discharges in the motor region of the cortex, helping to control seizure activity. Dilantin is also used to treat irregular heart rhythms. The effects of Dilantin on the body and brain are dose related. Small changes in blood levels of Dilantin can cause significant side effects.
Seizures
It may seem odd that a medication used to control seizure activity has the potential to cause seizures; but this is related to the very narrow therapeutic index of Dilantin. The Epilepsy Foundation advises that the dose range that provides the best therapeutic effect is very narrow. A decrease in a prescribed Dilantin dose can lead to increased seizure activity. Withdrawing Dilantin abruptly can cause status epilepticus or uncontrolled grand mal seizures. Patients must be educated to prevent this dangerous adverse effect. Dilantin must be taken as prescribed, and blood tests should be conducted to check blood levels.
Billie Ann Wilson, Ph.D., Margaret Shannon, Ph.D., and Kelly Shields Pharm.D., authors of "Pearson Nurse's Drug Guide 2010," emphasize that patients and caregivers must also understand that Dilantin interacts with many drugs. This results in increased potency of Dilantin. Folic acid, vitamin D, coumadin, oral contraceptives and many other anticonvulsants are a few examples of drugs that interact with Dilantin. Therapeutic blood levels can rise quickly to dangerous levels, causing drowsiness, confusion and seizures. Alcohol also potentiates (strengthens) Dilantin and should be avoided when taking Dilantin.
Cardiovascular Collapse
Dilantin has a similar inhibiting effect on electrical impulses in the heart as it does in the brain. Overdose of Dilantin causes a slow heart rate called bradycardia, and very low blood pressure, called hypotension. The respiratory rate drops and a person can experience cardiovascular collapse. When Dilantin is given intravenously, vital signs and level of consciousness are monitored closely to watch for this adverse reaction.
Severe Skin Reactions
Serious skin reactions can occur while taking Dilantin. Any sign of rash should be reported to a physician immediately. A scarlet fever-type reaction can occur, characterized by a measle-like rash, ulcers and hemorrhaging under the skin. Dilantin can cause necrolysis or death of tissue, especially if it infiltrates into tissues when given intravenously.
Gingival Hyperplasia
Dilantin is completely absorbed from the gastrointestinal tract. A very common side effect is overgrowth of gum tissue predominantly occurring in children and adolescents. In addition to this, constipation can be a frequent problem, as well as nausea and indigestion.
Nutrition Deficiencies
Because of the way Dilantin is absorbed and metabolized, deficiencies in vitamin D, folic acid, magnesium and calcium can occur. Ensure a balanced diet with supplements when food intake is restricted or diminished. Periodic lab work should be performed to check electrolyte levels. See a doctor if tremors, nystagmus, dizziness, and muscle twitching occur. These are symptoms of low magnesium.
References
- The Epilepsy Foundation: "Medicines for Epilepsy: Dilantin"
- "Pearson Nurse's Drug Guide 2010"; Wilson, B. A., Shannon, T. M., & Shields, K. M.; 2010
