Fosphenytoin is known by its marketing name of Cerebyx in the US as well as Prodilantin in European markets. This drug produces Phenytoin when introduced to the body as a prodrug, which is a drug that is non-active until metabolized. Considered to be much safer than the intravenously administered Phenytoin, Fosphenytoin has been approved for use since 1996.
Fosphenytoin is used only in a professional medical setting such as a hospital or clinic. It is most often prescribed for use in epileptic patients and to prevent and treat neurosurgical related convulsions or seizures.
How does Fosphenytoin work?
After being introduced to the body via injection route, Fosphenytoin changes to an anticonvulsant drug known as Phenytoin on a one to one ratio. Fosphenytoin itself is a prodrug in that it does not have any effect until it changes, which requires interaction with certain enzymes in the body.
Fosphenytoin affects the motor cortex of the brain, which is the area that controls movement, both voluntary and involuntary. Fosphenytoin works to stop the seizure activity from spreading, reducing the chance of the seizure becoming full blown, also known as grand mal.
Fosphenytoin is believed to stop the involuntary energy conduction activity in the brain cells of someone experiencing a seizure. By passing through the neuron cell membranes, Fosphenytoin serves to dampen abnormal energy synapses, normalizing activity and calming the seizure. This drug is intended for the short-term use of five days or less or until the patient can be assigned other drug treatment for long-term care.
Fosphenytoin has been determined to be faster acting than Phenytoin, which has proven to result in better control over seizures. Fosphenytoin is also tolerated well compared to Phenytoin, with a lower risk for heart rhythm and low blood pressure risks. Fosphenytoin additionally does not demonstrate a risk for purple glove syndrome, which is a skin condition sometimes severe enough to require amputation. Purple glove syndrome is associated with IV administration of Phenytoin.
Epilepsy is a brain condition that gives the patient seizures on a semi-regular basis. All brain activity is electrical, consisting of cellular communication back and forth. When a person has a seizure, it is the result of an explosion of electrical activity in the brain cells, which temporarily disrupt normal function.
The type of seizure a person has depends on the part of the brain that is affected by the energy burst. Not all seizures are epileptic in nature and not all seizures are controlled with drugs such as Fosphenytoin and Phenytoin.
Fosphenytoin, through its active drug ingredient of Phenytoin, directly affects brain activity at the cellular level, in the motor cortex portion of the brain. It is a very powerful drug and, due to the way it works, may cause adverse health effects that can require urgent medical attention. Notify your physician or medical staff if you exhibit any of the following symptoms:
Other patients experience unwanted health effects that are temporary in nature and disappear as the medication is absorbed into your system. If you do have the following symptoms, pass them along to your physician in case there is a way to eliminate or ease them:
Still other adverse health effects occur for some patients, so if your health changes in any way after being treated with Fosphenytoin, it is best to alert your physician to these changes to provide you with assistance, should it be required.
This medication is administered only in a hospital setting by a trained doctor, surgeon or nurse. Your dosage has been determined based on your particular condition and needs as well as many other factors.
In general, an injected dosage of Fosphenytoin for a patient with epileptic seizures is from 15 to 20 milligrams Phenytoin equivalents per kilogram of body weight, not to exceed 150 milligrams per minute intravenously. This should be followed by maintenance doses, as required. Other drugs may also be given at this time depending on the need required by the patient's health.
Patients will be monitored continuously with regard to blood pressure levels, function of the respiratory system and electrocardiogram analysis.
Patients younger than 17 years old are typically given the same 15 to 20 milligrams Phenytoin equivalents per kilogram of body weight as adult patients, also not to exceed 150 milligrams per minute of intravenous administration.
Hypersensitivity to other medications, certain foods, animals, artificial additives and dyes should be communicated to your health care provider to avoid any unwanted reactions to Fosphenytoin. Inform your health care provider if you are taking any other medications including those that are available over the counter, vitamin and herbal therapies or holistic remedies. As this drug will most likely be administered to you while you are hospitalized, make sure that your medical history is up to date on your latest drug treatments so that it can be referred to for possible interactions.
All drug therapies come with risk factors that will be explained to you by your physician. You will also be given a patient leaflet that you should read completely. Ask questions about any information contained in this leaflet that you don't understand.
Some medications are able to be used together without harm or reduced effectiveness of either drug. Combination therapies are a way to combat symptoms and make the patient more able to live a normal life. However, there are some drugs that should not be combined. The following medications should never be administered while you are being treated with Fosphenytoin:
The following medications are known to have adverse reactions with Fosphenytoin but may be critical to your health care. Make sure your physician knows if you take any of the following substances so that dosage amounts can be appropriately altered for safety and effectiveness:
The following drugs, while they may increase unwanted health effects with use of Fosphenytoin, may be necessary to your health care as well. Let your physician know if you are taking:
Consult with your physician on whether to eat prior or during your treatment with Fosphenytoin or whether certain foods should be eliminated from your diet altogether. You should also inform your doctor if you are a regular user of tobacco products or alcoholic beverages, as these could affect the way Fosphenytoin works for you. It is not advised that you consume anything ethanol based while taking Fosphenytoin.
Your full medical history should be communicated to your physician in case you have diseases that would be dangerously affected by chemotherapy treatment such as Fosphenytoin. Specifically, the following health conditions have been known to become worse or limit the effectiveness of this medication:
Your health condition will be closely monitored while you are being treated with Fosphenytoin to make sure it is controlling your condition and that you aren't suffering from any adverse health effects. Blood sample testing may be involved in this monitoring process.
Fosphenytoin has been known to pose a risk to unborn children and should not be used in women who are pregnant or who may become pregnant. An effective birth control method is advised for use in women being treated with this medication. If you become pregnant while being treated with Fosphenytoin, inform your health care provider as soon as possible.
Data from studies on women who are breastfeeding has not been provided with any level of confidence that determines a risk to children and infants as far as transmission of Fosphenytoin through breast milk. Use of this medication on women who are nursing should be determined with regard to their health needs and the health of their children.
No data has been provided from studies on pediatric or geriatric patients with regard to the effectiveness of Fosphenytoin or with regard to increased risks. It is believed to be appropriate for these age groups, with the caution that geriatric patients may have kidney, heart or liver problems that may create an increased risk for them.
Delavirdine, also marketed as Rescriptor, is a medication that should not be used with Fosphenytoin treatment as the effect on your condition that is expected of Delavirdine will not be met if taking Fosphenytoin.
Some patients become lightheaded, pass out or are dizzy and less alert than they normally are. For this reason, driving, operating heavy machinery or power tools should not be done while you are on this medication.
Do not discontinue using the medication you are prescribed post injected dose of Fosphenytoin as your seizure condition could return if you do.
Be alert for signs of Drug Reaction with Eosinophilia and Systemic Symptoms condition, or DRESS, with use of Fosphenytoin, which includes:
Alert your physician if you feel as if your skin is burning or if you have needles and pins sensations or itching and tingling after your injection. Symptoms including hives or rashes on the skin or other hypersensitivities should also be reported to your doctor immediately.
This medication puts patients at risk for a skin condition called PGS, which can potentially be serious. Also known as purple glove syndrome, PGS can be indicated by signs of discoloration, swelling or pain at the site of the injection of Fosphenytoin. Let your health care professional know if your injection site appears strange in any way.
Blood sugar levels can be affected by the use of Fosphenytoin and diabetic patients should especially be monitored for glucose levels. Your doctor will need to know if you are diabetic or pre-diabetic if you have been given an injection of Fosphenytoin.
Avoid consuming alcoholic beverages while you are being treated with Fosphenytoin. Seek assistance if you require it during this time.
Your birth control pills may not be effective if you have been treated with Fosphenytoin injection, so use alternate forms of birth control while you are being administered this drug. Discuss your birth control options with your health care provider.
Many medications, vitamins and mineral supplements interact adversely with Fosphenytoin. Avoid taking any other medications while you are being treated with this drug, including over-the-counter, herbal, and holistic or vitamin supplements.
Fosphenytoin will be stored and administered in a hospital or medical clinic setting only, with storage according to the manufacturer's instructions carried out by the professional staff.
The manufacturer recommends that the vials of medication be stored in their original packaging under refrigerated conditions. While Fosphenytoin can be stored at room temperature, it should be discarded after 48 hours. Any opened Fosphenytoin should be used immediately or discarded according to safety instructions and local guidelines.
Fosphenytoin is a prodrug that isn't active until it is injected into the body, when it changes into Phenytoin, a powerful anti-seizure medication used to prevent and treat convulsions and seizures that may result when a patient has neurosurgery as well as those experienced by patients with epilepsy. Proven to be safer than an administration of Phenytoin itself, it provides better tolerance at the injection site and has less of a risk of causing cardiac and blood pressure issues. The cost of Fosphenytoin, however, is higher than that of Phenytoin, so it is typically administered to patients who cannot tolerate intravenous route drugs or those who could not withstand PGS, if infected.
By blocking certain channels in the motor cortex region of the brain, which is the central portion, Fosphenytoin effectively calms hyperactive electrical activity generated in the brain of patients who are epileptic. Fosphenytoin calms this activity and halts the seizure.
This medication is only for temporary administration via injection and should not be used for longer than 5 days to control the seizure condition. After this, the patient will be prescribed oral medication to take control of their seizures. Dosage amount, storage safety and other considerations are the responsibility of professional medical staff located at the hospital or clinic where Fosphenytoin is administered.
Unwanted health effects may include confusion, drowsiness, nervous demeanor, nausea, constipation, skin symptoms, uncontrolled body, eye or facial movements, headaches and insomnia or upset stomach. Serious, severe or prolonged symptoms should be reported to your physician immediately. Fosphenytoin poses a risk of PGS, an infection of the injection site as well as liver damage and DRESS syndrome. Changes to your overall health or wellbeing should be communicated to your health care professional immediately to avoid long-term health damage.
Patients are instructed not to consume alcoholic beverages while being treated with Fosphenytoin. Patients should also avoid taking any other medications with this drug, whether they are prescription or non-prescription, as the list of interactivity that causes adverse health effects is extensive. Patients may be at risk of heart failure if this drug is administered too quickly. Patients are also at risk if they have liver or kidney diseases or if they are diabetic. Make sure your full medical history is available to your doctor should you require treatment with Fosphenytoin.
Most patients are able to benefit from the effects of Fosphenytoin, should they need emergency brain seizure treatment. Women who are pregnant or who are nursing should avoid this treatment unless it is an emergency, as it can pose a risk to their unborn children or infants. Geriatric patients who have kidney, liver or cardiac diseases should also be administered Fosphenytoin with caution.