Phenytek
Phenytek is an extended-release brand-name formulation of phenytoin sodium, an anticonvulsant (anti-seizure) medication. It functions by stabilizing neuronal membranes and limiting the spread of seizure activity in the brain. Because phenytoin has a narrow therapeutic window and exhibits non-linear pharmacokinetics, serum level monitoring is highly recommended to ensure efficacy and avoid toxicity.
Dosage by Body Weight
Dosage must be strictly individualized. For adults, the typical starting dose is 100 mg to 120 mg three times daily, or 300 mg once daily once a maintenance level is established. Pediatric dosing is usually calculated by body weight (starting at 5 mg/kg/day in divided doses) and adjusted based on clinical response and blood levels. Do not switch brands without supervising medical guidance.
- Body Weight
- Below 5 kg
- Dose
- Not routine
- Frequency
- Use only if prescribed
- Tracking Notes
- Safety and efficacy in newborns and young infants are highly variable; close serum level monitoring is mandatory.
- Body Weight
- 5-7 kg
- Dose
- 25 mg to 35 mg daily
- Frequency
- Divided into 2 to 3 doses
- Tracking Notes
- Calculated based on initial 5 mg/kg/day. Dosage adjustments should be made slowly under specialist supervision.
- Body Weight
- 8-10 kg
- Dose
- 40 mg to 50 mg daily
- Frequency
- Divided into 2 to 3 doses
- Tracking Notes
- Requires periodic therapeutic drug monitoring (TDM) to ensure blood levels remain within the 10-20 mcg/mL therapeutic range.
- Body Weight
- 11-15 kg
- Dose
- 55 mg to 75 mg daily
- Frequency
- Divided into 2 to 3 doses
- Tracking Notes
- Maintenance dose may eventually be increased to 4 to 8 mg/kg/day based on clinical response and tolerance.
- Body Weight
- 16-20 kg
- Dose
- 80 mg to 100 mg daily
- Frequency
- Divided into 2 to 3 doses
- Tracking Notes
- Do not exceed standard pediatric limits unless carefully monitored. Watch for signs of toxicity such as nystagmus or ataxia.
| Body Weight | Dose | Frequency | Tracking Notes |
|---|---|---|---|
| Below 5 kg | Not routine | Use only if prescribed | Safety and efficacy in newborns and young infants are highly variable; close serum level monitoring is mandatory. |
| 5-7 kg | 25 mg to 35 mg daily | Divided into 2 to 3 doses | Calculated based on initial 5 mg/kg/day. Dosage adjustments should be made slowly under specialist supervision. |
| 8-10 kg | 40 mg to 50 mg daily | Divided into 2 to 3 doses | Requires periodic therapeutic drug monitoring (TDM) to ensure blood levels remain within the 10-20 mcg/mL therapeutic range. |
| 11-15 kg | 55 mg to 75 mg daily | Divided into 2 to 3 doses | Maintenance dose may eventually be increased to 4 to 8 mg/kg/day based on clinical response and tolerance. |
| 16-20 kg | 80 mg to 100 mg daily | Divided into 2 to 3 doses | Do not exceed standard pediatric limits unless carefully monitored. Watch for signs of toxicity such as nystagmus or ataxia. |
Formulation
Purpose
Control of generalized tonic-clonic (grand mal) and complex partial seizures, and prevention or treatment of seizures occurring during or after neurosurgery.
Generic Name
Phenytoin Sodium (Extended)Scheduled Drug
No. This medicine is generally not treated as a scheduled/prescription-only drug in common consumer references, but local rules may vary.