Place Your Advertisement Here. All ad revenues support the mission of the Epilepsy Therapy Project.
 
Thu, 5/24/2012

Sign up for our Mailing List
Receive your weekly epilepsy news in an easy to read email format every Wednesday



Place Your Advertisement Here

Take control of your epilepsy and seizures. Seizure management has never been easier.

TAKE CONTROL TODAY

Interactions of Dilantin with other medications: Professional

Topics List
New comprehensive downloadable medication sheet
  • Additional information on this drug and how to use it.
  • A starting point for discussion with your doctor.
  • Answers to frequently asked questions.

When prescribing Dilantin, question patients or family members extensively about the use of prescription and OTC medications, herbal products, vitamins, alcohol, and other substances. Interactions with phenytoin are common. Usually all necessary medications can be used, but the dosages may need to be adjusted to achieve therapeutic levels.

Effects of Dilantin (phenytoin) on other drugs
If combination therapy using phenytoin and another antiepileptic drug (AED) is begun, the dosage of the initial AED may need to be adjusted. Similarly, if a medication previously used in combination therapy is to be stopped, the dosage of the remaining AED may need to be changed.

Phenytoin will lower the blood levels of other AEDs:

  • carbamazepine
  • clonazepam
  • lamotrigine
  • oxcarbazepine
  • tiagabine
  • topiramate
  • valproate
  • zonisamide

Phenytoin also will lower the blood levels of other types of medication:

  • acetaminophen
  • amiodarone
  • aminophylline
  • chloramphenicol
  • cholecalciferol
  • cyclosporine
  • dicoumarol
  • digoxin
  • disopyramide
  • doxycycline
  • estrogens
  • felodipine
  • folic acid
  • furosemide
  • itraconazole (large effect)
  • levodopa
  • meperidine
  • methadone
  • metronidazole
  • mexiletine
  • misonidazole
  • nisoldipine
  • oral contraceptives
  • paroxetine
  • phenobarbital
  • praziquantel
  • prednisone/prednisolone
  • psoralens
  • quetiapine
  • quinidine
  • rifampin
  • theophylline
  • topotecan
  • tirilazad
  • tricyclic antidepressants
  • vitamin D
  • warfarin (variable effect)

Phenytoin may increase the blood levels of a few other drugs:

  • phenobarbital (changes insignificant in most patients)
  • warfarin (variable effect)

Effects of other drugs on Dilantin (phenytoin)
Some substances that are safe to use in small amounts with phenytoin can be a problem if larger amounts are used. For instance, one or two drinks of alcohol will seldom affect the level of phenytoin in any important way, but if a person who does not often consume alcohol drinks a moderate or large amount, the level of phenytoin in the blood may be significantly increased. On the other hand, a person who chronically abuses alcohol may experience decreased levels of phenytoin and be more susceptible to seizures.

Aspirin and other salicylates are generally safe to take with phenytoin at the usual doses. If more than 1500 mg per day is taken, however, the total level of phenytoin in the blood may be decreased but the free level may increase. Effects may vary.

Medications that contain calcium, including some antacids, should not be taken at the same time as phenytoin, to prevent absorption problems. They can be used, but the times should be staggered.

A few other AEDs may decrease the blood level of phenytoin:

  • carbamazepine (varies by individual)
  • phenobarbital (varies by individual)
  • valproate (variable)
  • vigabatrin

Other medications that decrease the blood level of phenytoin include:

  • alcohol (chronic abuse)
  • aminophylline
  • antacids containing calcium (if taken together)
  • ciprofloxacin
  • folic acid
  • methotrexate
  • reserpine
  • rifampin
  • sucralfate
  • vinblastine

Other AEDs that increase the blood level of phenytoin include:

  • carbamazepine (varies by individual)
  • clobazam
  • diazepam
  • ethosuximide
  • felbamate
  • methsuximide
  • oxcarbazepine
  • phenobarbital (varies by individual)
  • topiramate
  • valproate

Other medications that increase the blood level of phenytoin include:

  • alcohol (occasional moderate or large intake)
  • amiodarone
  • aspirin (more than 1500 mg/d)
  • chloramphenicol
  • chlordiazepoxide
  • cimetidine
  • dicoumarol
  • diltiazem
  • disulfiram
  • estrogens
  • fluconazole
  • fluoxetine
  • halothane
  • isoniazid
  • itraconazole
  • methylphenidate
  • metronidazole
  • miconazole & flucytosine
  • omeprazole
  • phenothiazines
  • propoxyphene
  • ranitidine
  • sertraline
  • sulfonamides
  • ticlopidine
  • tolbutamide
  • trazodone
  • trimethoprim
  • warfarin

AED Interaction Sheets:
Seizure drugs are often affected by drug-drug interactions. Print these informative sheets for practical help.


Welcome to the Wiki. This space is created for epilepsy.com members to share their own experiences and expertise to help refine and expand the discussion around important topics.

No members have yet contributed to this topic. If you are not yet an epilepsy.com member, register today to get started on this Wiki topic and the many other advantages of being a member. If you are a member and wish to be the first to edit this Wiki topic, please make sure to login, then click on the orange "Start Wiki" button at the top of this page. Or, learn more about Wikis.


Related Content

View all Forums
 
New - Does a seizure disorder = epilepsy?
Created by at3/28/08 - 9:15 pm|8 Comments
New - Hello Im new here and I have a question
Created by at3/6/08 - 2:30 pm|3 Comments
New - Changing AEDs while pregnant?
Created by at2/26/08 - 10:21 pm|1 Comment
EEG while on Keppra/Dilantin...shows normal...duh?
Created by at2/15/08 - 1:51 pm|7 Comments
New - Smoking marijuana and drinking
Created by at2/6/08 - 11:30 pm|4 Comments
New - Keppra and Alcohol
Created by at2/4/08 - 10:49 am|16 Comments
New - Dilantin
Created by at2/1/08 - 5:28 pm|9 Comments
YOUR EXPERIENCES
Created by at1/20/08 - 8:30 pm|1 Comment
Dilantin vs Phenytoin
Created by at1/14/08 - 8:30 pm|4 Comments
New - Another Drinking Discussion
Created by at12/12/07 - 3:50 pm|3 Comments