The recommended starting dose of phenytoin (the active ingredient in Phenytek) for adults is 100 mg (extended release) three times daily. Because Phenytek is not available in a 100 mg form, a different phenytoin product must be used. However, once your healthcare provider has found a good phenytoin dose, you may be switched to one Phenytek 300 mg capsule per day.
The dose of Phenytek® (phenytoin sodium) that your healthcare provider recommends will vary depending on a number of factors, including:
- Your age and weight
- The amount of Phenytek in your blood (measured using a blood test)
- Other medications you are taking
- Other medical conditions you have.
As is always the case, do not adjust your Phenytek dose unless your healthcare provider specifically instructs you to do so.
When starting phenytoin for the first time, it is recommended to take phenytoin 100 mg (extended release) three times daily. Phenytek does not come in a 100 mg dose, so a different phenytoin product (such as Dilantin® or generic phenytoin) must be used. Most likely, your healthcare provider will measure the amount of phenytoin in your blood (using a blood test) and adjust your dose as necessary.
After your healthcare provider has found a good phenytoin dose for you, you can be switched to one Phenytek 300 mg capsule per day. Sometimes, a dose of Phenytek 200 mg three times daily may be necessary.
For children, the starting phenytoin dose is based on weight: 5 mg per kg per day (about 2.3 mg per pound per day), divided into two or three doses per day. Because Phenytek comes in strengths that are relatively high (200 mg and 300 mg) compared to other phenytoin products, Phenytek usually cannot be used when starting a child on phenytoin.
Once an appropriate dose is determined (as some dose adjustment is usually required), Phenytek can be used in place of other phenytoin products. However, the available Phenytek doses may still be too high for many children.