What is the therapeutic serum drug range for phenytoin (Dilantin)?

The therapeutic serum drug range for phenytoin, commonly known by its brand name Dilantin, is crucial for treatment effectiveness while minimizing the risk of toxicity. The correct range of 10 to 20 mcg/mL is based on clinical guidelines that support optimal management of seizure disorders. Within this range, phenytoin effectively stabilizes neuronal activity and helps prevent seizures in patients with epilepsy.

Measurements of drug levels below 10 mcg/mL may be ineffective, leading to breakthrough seizures, while levels exceeding 20 mcg/mL can result in toxicity, manifesting as neurological complications such as ataxia, nystagmus, or even more serious side effects. Hence, maintaining serum levels within this therapeutic range is essential for ensuring patient safety and achieving therapeutic efficacy.

This understanding underscores the importance of continuous monitoring and adjusting dosages based on individual patient needs, response to therapy, and potential interactions with other medications.