Dilantin (Phenytoin) Side Effects, Important Information, Before Taking & What to Avoid

Dilantin is an externally administered medicine. Its formulation contains phenytoin as its primary ingredient. This primary ingredient is an anti-convulsing drug, i.e., an anti-seizure medication.


It is used for the prevention and treatment of certain seizures. It is important to note that it does not cure any of them; it helps in controlling your condition and is used with a combination of other drugs.

It may also be used for other purposes not mentioned in this guide.


Side effects of Dilantin:

Dilantin, just like other medications, too has some side effects. These range from mild to severe and must be reported immediately.

Some of the common side effects that are considered to be mild in nature are as follows:

  • Dizziness
  • Feeling drowsy
  • Confusion and nervousness
  • Nausea and vomiting
  • Constipation
  • Tremors
  • Slurred speech
  • Poor balance due to impaired muscular coordination
  • Signs of allergy such as a rash
  • Abnormal eye movement
  • A headache
  • Sleep disorders, e.g., insomnia


Most of these side effects occur at the start of the treatment and perish within a day or two as it does not take long for the body to adjust and get accustomed to the presence of the medicine. However, they may persist and start to worsen, triggering serious medical conditions. Therefore, seek medical help promptly if any side effect is experienced.


Some of the potential side effects Dilantin is known to cause are:

  • Hyperactivity
  • Suicidal thoughts
  • Extreme weakness
  • Signs of a severe allergic reaction; skin rash, swollen glands, patches, etc.
  • Severe pain in the bones and muscle
  • Fever accompanied by chills
  • Jaundice
  • Clay-colored stools indicating a liver disorder



Note that other side effects not listed in this guide may also be experienced. Usually, doctors and/or pharmacists inform the patients about the side effects they are likely to experience at the start of their treatment.

For further queries and concerns regarding this, you may consult your doctor and/or pharmacist.


How to use Dilantin

Before starting, you are advised to read the direction on the prescription label and follow them carefully.

Dilantin is administered orally. Usually, it is prescribed once a day. However, if your doctor directs you otherwise, you are to follow his/her instructions. Take timely and balanced doses. Swallow the extended-release capsules without chewing or crushing. Chew the chewable tablets before swallowing. You may take Dilantin with or without food.


Precautions for Dilantin:

  • Neither use nor prescribe it without the doctor’s prescription.
  • Dilantin makes birth control pills less effective; thus, you are advised to go for mechanical contraception while taking this medicine.
  • It may interact negatively with certain medications. Thus, give your doctor the list of all the medicines, if any, that you use for safety.
  • It is not recommended under certain conditions. Make sure to provide your doctor your medical history to avoid any inconvenience.
  • If pregnant or nursing a baby, inform your doctor immediately.
  • Keep it away from children’s reach, moisture, sunlight, and heat.
  • Don’t take calcium products with the medicine.