Medical Editor: John P. Cunha, DO, FACOEP
Dilantin Kapseals (extended phenytoin sodium) is an antiepileptic drug used to control generalized tonic-clonic (grand mal) and complex partial (psychomotor, temporal lobe) seizures and to prevent and treat seizures occurring during or following neurosurgery. Dilantin Kapseals is available in generic form. Common side effects of Dilantin Kapseals include headache, nausea, vomiting, constipation, dizziness, spinning sensation, drowsiness, trouble sleeping, or nervousness.
Patients who have received no previous treatment may be started on a dose of one 100-mg Dilantin three times daily and the dosage then adjusted to suit individual requirements. For most adults, the maintenance dosage will be one capsule three to four times a day. Dilantin Kapseals may interact with azapropazone, delavirdine, dofetilide, etravirine, nisoldipine, rilpivirine, colesevelam, molindone, pyridoxine (vitamin B6), sucralfate, sulfa drugs, telithromycin, amiodarone, azole antifungals, cimetidine, antibiotics, estrogens, isoniazid, rifamycins, St. John's wort, other anti-seizure medicines, drugs to treat cancer, steroids, cyclosporine, felodipine, quetiapine, quinidine, theophylline, vitamin D, warfarin, phenothiazines, antidepressants, or hormonal birth control such as pills, patch, or ring. Tell your doctor all medications and supplements you use. Dilantin Kapseals are not recommended for use during pregnancy. It may harm a fetus. Breastfeeding is not recommended while taking Dilantin Kapseals because this drug appears to pass in low concentrations into breast milk. Withdrawal symptoms may occur if you suddenly stop taking this medication.
Our Dilantin Kapseals (extended phenytoin sodium) Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
Phenytoin may cause swelling and bleeding of the gums. Massage your gums and brush and floss your teeth regularly to minimize this problem. See your dentist regularly.
Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.
Tell your doctor immediately if any of these unlikely but serious side effects occur: unusual eye movements, loss of coordination, slurred speech, confusion, muscle twitching, double or blurred vision, tingling of the hands/feet, facial changes (e.g., swollen lips, butterfly-shaped rash around the nose/cheeks), excessive hair growth, increased thirst or urination, unusual tiredness, bone or joint pain, easily broken bones.
A small number of people who take anticonvulsants for any condition (such as seizure, bipolar disorder, pain) may experience depression, suicidal thoughts/attempts, or other mental/mood problems. Tell your doctor immediately if you or your family/caregiver notice any unusual/sudden changes in your mood, thoughts, or behavior including signs of depression, suicidal thoughts/attempts, thoughts about harming yourself.
For males, in the very unlikely event you have a painful or prolonged erection lasting 4 or more hours, stop using this drug and seek immediate medical attention, or permanent problems could occur.
Get medical help right away if any of these rare but very serious side effects occur: uncontrolled muscle movements, muscle weakness/pain, swollen glands (lymph nodes), stomach/abdominal pain, persistent nausea/vomiting, yellowing eyes or skin, dark urine, easy bruising/bleeding, signs of infection (e.g., persistent sore throat or fever), chest pain, trouble breathing, irregular heartbeat.
A serious allergic reaction to this drug is unlikely, but seek immediate medical attention if it occurs. Symptoms of a serious allergic reaction include: rash, high fever, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.
This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.
In the US -
Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.
Read the entire patient information overview for Dilantin Kapseals (Extended Phenytoin Sodium Capsules)
Body as a Whole
The most common adverse reactions encountered with phenytoin therapy are nervous system reactions and are usually dose-related. Reactions include nystagmus, ataxia, slurred speech, decreased coordination, somnolence, and mental confusion. Dizziness, vertigo, insomnia, transient nervousness, motor twitchings, paresthesias, and headaches have also been observed. There have also been rare reports of phenytoin-induced dyskinesias, including chorea, dystonia, tremor, and asterixis, similar to those induced by phenothiazine and other neuroleptic drugs. Cerebellar atrophy has been reported, and appears more likely in settings of elevated phenytoin levels and/or long-term phenytoin use.
A predominantly sensory peripheral polyneuropathy has been observed in patients receiving long-term phenytoin therapy.
Skin And Appendages
Dermatological manifestations sometimes accompanied by fever have included scarlatiniform or morbilliform rashes. A morbilliform rash (measles-like) is the most common; other types of dermatitis are seen more rarely. Other more serious forms which may be fatal have included bullous, exfoliative or purpuric dermatitis, Stevens-Johnson syndrome, and toxic epidermal necrolysis (see WARNINGS section). There have also been reports of hypertrichosis.
Hematologic And Lymphatic System
Hematopoietic complications, some fatal, have occasionally been reported in association with administration of phenytoin. These have included thrombocytopenia, leukopenia, granulocytopenia, agranulocytosis, and pancytopenia with or without bone marrow suppression. While macrocytosis and megaloblastic anemia have occurred, these conditions usually respond to folic acid therapy. Lymphadenopathy including benign lymph node hyperplasia, pseudolymphoma, lymphoma, and Hodgkin's disease have been reported (see WARNINGS section).
Altered taste sensation including metallic taste.
Read the entire FDA prescribing information for Dilantin Kapseals (Extended Phenytoin Sodium Capsules)
© Dilantin Kapseals Patient Information is supplied by Cerner Multum, Inc. and Dilantin Kapseals Consumer information is supplied by First Databank, Inc., used under license and subject to their respective copyrights.