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Dilantin 125

Last reviewed on RxList: 7/30/2019
Dilantin 125 Side Effects Center

Last reviewed on RxList 7/30/2019

Dilantin-125 (phenytoin oral) Suspension is an anti-epileptic drug, also called an anticonvulsant used to control seizures. Dilantin-125 is not made to treat all types of seizures. Dilantin-125 is available in generic form. Common side effects of Dilantin-125 include:

  • headache,
  • nausea,
  • vomiting,
  • constipation,
  • dizziness,
  • drowsiness,
  • sleep problems (insomnia),
  • nervousness, or
  • swelling and bleeding of the gums.

Tell your doctor if you have unlikely but serious side effects of Dilantin-125 including:

  • unusual eye movements,
  • loss of balance or coordination,
  • slurred speech,
  • confusion,
  • muscle twitching,
  • double or blurred vision,
  • tingling of the hands or feet,
  • facial changes (e.g., swollen lips, butterfly-shaped rash around the nose or cheeks),
  • excessive hair growth,
  • increased thirst or urination,
  • unusual tiredness,
  • bone or joint pain, or
  • easily broken bones.

Dosage of Dilantin-125 is individualized. Patients who have received no previous treatment may be started on one teaspoonful (5 mL) of Dilantin-125 Suspension three times daily, and the dose is then adjusted to suit individual requirements. Dilantin-125 may interact with stomach acid reducers, sedatives, estrogen hormone replacement, phenothiazines, disulfiram, methylphenidate, sulfa drugs, carbamazepine, sucralfate, molindone, phenobarbital, valproic acid, divalproex sodium, steroids, antidepressants, antibiotics, digoxin, furosemide, and theophylline. Tell your doctor all medications and supplements you use. During pregnancy, Dilantin-125 should be used only if prescribed. It may harm a fetus. Untreated seizures are a serious condition that can harm both a pregnant woman and her fetus; do not stop taking this medication unless directed by your doctor. If you are planning pregnancy, become pregnant, or think you may be pregnant, talk to your doctor. Since birth control pills, patches, implants, and injections may not work if taken with this medication, discuss birth control with your doctor. This drug passes into breast milk. Consult your doctor before breastfeeding. Abrupt withdrawal of this medication can cause status epilepticus.

Our Dilantin-125 (phenytoin oral) Suspension 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.


Epilepsy: Symptoms, Causes and Treatment See Slideshow
Dilantin 125 Consumer Information

Get emergency medical help if you have signs of an allergic reaction (hives, difficult breathing, swelling in your face or throat) or a severe skin reaction (fever, sore throat, burning in your eyes, skin pain, red or purple skin rash that spreads and causes blistering and peeling).

Seek medical treatment if you have a serious drug reaction that can affect many parts of your body. Symptoms may include: skin rash, fever, swollen glands, muscle aches, severe weakness, unusual bruising, or yellowing of your skin or eyes.

Report any new or worsening symptoms to your doctor, such as: mood or behavior changes, anxiety, panic attacks, trouble sleeping, or if you feel impulsive, irritable, agitated, hostile, aggressive, restless, hyperactive (mentally or physically), more depressed, or have thoughts about suicide or hurting yourself.

Call your doctor at once if you have:

  • slow or uneven heartbeats, chest pain, fluttering in your chest, and dizziness (like you might pass out);
  • any skin rash, no matter how mild;
  • fever, chills, sore throat, swollen glands;
  • red or swollen gums, mouth sores;
  • easy bruising, unusual bleeding, purple or red spots under your skin; or
  • liver problems--loss of appetite, upper stomach pain, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes).

Common side effects may include:

  • drowsiness, confusion;
  • slurred speech;
  • abnormal eye movement; or
  • problems with balance or muscle movement.

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.

Read the entire detailed patient monograph for Dilantin 125 (Phenytoin Oral Suspension)


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Dilantin 125 Professional Information


The following serious adverse reactions are described elsewhere in the labeling:

  • Withdrawal Precipitated Seizure, Status Epilepticus [see WARNINGS AND PRECAUTIONS]
  • Suicidal Behavior and Ideation [see WARNINGS AND PRECAUTIONS]
  • Serious Dermatologic Reactions [see WARNINGS AND PRECAUTIONS]
  • Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS)/Multiorgan Hypersensitivity [see WARNINGS AND PRECAUTIONS]
  • Hypersensitivity [see WARNINGS AND PRECAUTIONS]
  • Cardiac Effects [see WARNINGS AND PRECAUTIONS]
  • Hepatic Injury [see WARNINGS AND PRECAUTIONS]
  • Hematopoietic Complications [see WARNINGS AND PRECAUTIONS]
  • Effects on Vitamin D and Bone [see WARNINGS AND PRECAUTIONS]
  • Exacerbation of Porphyria [see WARNINGS AND PRECAUTIONS]
  • Teratogenicity and Other Harm to the Newborn [see WARNINGS AND PRECAUTIONS]
  • Hyperglycemia [see WARNINGS AND PRECAUTIONS]

The following adverse reactions associated with the use of DILANTIN were identified in clinical studies or postmarketing reports. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.

Body as a Whole: Allergic reactions in the form of rash and rarely more serious forms and DRESS have been observed, as has angioedema [see WARNINGS AND PRECAUTIONS]. Anaphylaxis has also been reported.

There have also been reports of coarsening of facial features, systemic lupus erythematosus, periarteritis nodosa, and immunoglobulin abnormalities.

Digestive System: Acute hepatic failure, toxic hepatitis, liver damage, nausea, vomiting, constipation, enlargement of the lips, and gingival hyperplasia.

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 AND PRECAUTIONS].

Laboratory Test Abnormality: Phenytoin may decrease serum concentrations of thyroid hormone (T4 and T3), sometimes with an accompanying increase in thyroid-stimulating hormone (TSH), but usually in the absence of clinical hypothyroidism. Phenytoin may also produce lower than normal values for dexamethasone or metyrapone tests. Phenytoin may cause increased serum levels of glucose [see WARNINGS AND PRECAUTIONS], alkaline phosphatase, and gamma glutamyl transpeptidase (GGT).

Nervous System: 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 [see WARNINGS AND PRECAUTIONS].

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, acute generalized exanthematous pustulosis, Stevens-Johnson syndrome, and toxic epidermal necrolysis [see WARNINGS AND PRECAUTIONS]. There have also been reports of hypertrichosis and urticaria.

Special Senses: Altered taste sensation including metallic taste.

Urogenital: Peyronie's disease

Read the entire FDA prescribing information for Dilantin 125 (Phenytoin Oral Suspension)


If you have had a seizure, it means you have epilepsy. See Answer
Related Resources for Dilantin 125

Read the Dilantin 125 User Reviews »

© Dilantin 125 Patient Information is supplied by Cerner Multum, Inc. and Dilantin 125 Consumer information is supplied by First Databank, Inc., used under license and subject to their respective copyrights.


Epilepsy: Symptoms, Causes and Treatment See Slideshow

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