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Phenacemide (Systemic)

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Phenacemide (Systemic)

Another commonly used name is phenacetylcarbamide .


Phenacemide (fe-NASS-e-mide) is used to control certain seizures in the treatment of epilepsy. This medicine acts on the central nervous system (CNS) to reduce the number and severity of seizures.

Phenacemide is available only with your doctor's prescription in the following dosage form:


    • Tablets

Special Considerations

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For phenacemide, the following should be considered:


Tell your doctor if you have ever had any unusual or allergic reaction to phenacemide or any other anticonvulsant medicines in the past. Also tell your health care professional if you are allergic to any other substances, such as foods, preservatives, or dyes.


Phenacemide has been reported to cause birth defects when taken by the mother during pregnancy. However, this medicine may be necessary to control seizures in some pregnant patients. Be sure you have discussed this with your doctor. In addition, when taken during pregnancy, phenacemide may cause a bleeding problem in the mother during delivery and in the newborn. This may be prevented by giving vitamin K to the mother 1 month before and during delivery, and to the baby immediately after birth.


It is not known whether this medicine passes into breast milk.


Although there is no specific information comparing use of phenacemide in children with use in other age groups, this medicine is not expected to cause different side effects or problems in children than it does in adults.

Older adults

Many medicines have not been studied specifically in older people. Therefore, it may not be known whether they work exactly the same way they do in younger adults. Although there is no specific information comparing use of phenacemide in the elderly with use in other age groups, this medicine is not expected to cause different side effects or problems in older people than it does in younger adults.

Other medicines

Although certain medicines should not be used together at all, in other cases 2 different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking phenacemide, it is especially important that your health care professional know if you are taking the following:

    • Other anticonvulsants-Use of phenacemide may increase the chance of serious side effects

Other medical problems

The presence of other medical problems may affect the use of phenacemide. Make sure you tell your doctor if you have any other medical problems, especially:

    • Blood disease or

    • Kidney disease or

    • Liver disease or

    • Personality disorder (mental illness)-Phenacemide may make the condition worse


To control your medical problem, take this medicine every day exactly as ordered by your doctor. Do not take more or less of it than your doctor ordered. To help you remember to take the medicine at the correct times, try to get into the habit of taking it at the same times each day.


The dose of phenacemide will be different for different patients. Follow your doctor's orders or the directions on the label . The following information includes only the average doses of phenacemide. If your dose is different, do not change it unless your doctor tells you to do so:

    • Adults-Oral, at first, 500 milligrams three times a day. After one week, your doctor may add an additional 500 milligram dose to be taken upon arising if needed. In the third week, your doctor may add another 500 milligram dose to be taken at bedtime if needed. Your doctor may increase your dose further. However, the dose is usually not more than 5000 milligrams a day.

    • Children 5 years of age and older-Oral, at first, 250 milligrams three times a day. The doctor may increase the dose further. However, the dose is usually not more than 1500 milligrams a day.

    • Children up to 5 years of age-Dose must be determined by the doctor.

Missed dose

If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.


To store this medicine:

    • Keep out of the reach of children.

    • Store away from heat and direct light.

    • Do not store in the bathroom, near the kitchen sink, or in other damp places. Heat or moisture may cause the medicine to break down.

    • Do not keep outdated medicine or medicine no longer needed. Be sure that any discarded medicine is out of the reach of children.


Your doctor should check your progress at regular visits , especially during the first few months of treatment with this medicine. During this time, the amount of medicine you are taking may have to be changed often to meet your individual needs.

If you have been taking phenacemide regularly, do not stop taking it without first checking with your doctor. Your doctor may want you to decrease gradually the amount you are taking before stopping completely. This will help reduce the possibility of seizures.

Be sure to tell your doctor as soon as possible if you have a sore throat, fever, or general feeling of tiredness, or if you notice any unusual bleeding or bruising , such as reddish or purplish spots on skin, or recurring nosebleeds or bleeding gums.

Also, be sure to tell your doctor as soon as possible if you or your family notice any changes in your behavior or mood , such as aggressiveness, depression, or a decreased interest in your surroundings.

This medicine will add to the effects of alcohol and other CNS depressants (medicines that cause drowsiness). Some examples of CNS depressants are antihistamines or medicine for hay fever, other allergies, or colds; sedatives, tranquilizers, or sleeping medicine; prescription pain medicine or narcotics; barbiturates; other medicine for seizures; muscle relaxants; or anesthetics, including some dental anesthetics. Check with your doctor before taking any of the above while you are using this medicine .

This medicine may cause some people to become dizzy or drowsy. Make sure you know how you react to this medicine before you drive, use machines, or do anything else that could be dangerous if you are dizzy or are not alert .

Phenacemide may cause some serious side effects, including behavior or mental changes, blood problems, liver problems, or kidney problems. You and your doctor should discuss the good this medicine will do as well as the risks of receiving it.

Check with your doctor as soon as possible if any of the following side effects occur:

More common

Behavior or mood changes.


Blood in urine; dark-colored urine; difficulty in breathing, shortness of breath, wheezing, or tightness in chest; drowsiness; flu-like symptoms (fever with or without chills, headache, body ache); nausea or vomiting; skin rash; sore throat and fever; swelling of face, feet, or lower legs; swollen or painful glands; unusual bleeding or bruising; unusual tiredness or weakness; weight gain; white spots, sores, or ulcers on lips, or in mouth or throat; yellow eyes or skin.

Symptoms of overdose

(in the order in which they may occur) Unusual excitement, nervousness, or irritability; clumsiness or unsteadiness; drowsiness (severe).

Other side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. However, check with your doctor if any of the following side effects continue or are bothersome:

More common

Drowsiness; headache; loss of appetite.

Less common or rare

Dizziness; fever; muscle pain; pounding heartbeat; tingling, burning, or prickly sensations; trouble in sleeping; unusual tiredness or weakness; weight loss.

Other side effects not listed above may also occur in some patients. If you notice any other effects, check with your doctor.

May 26, 1998

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