Evaluation of Therapeutic Drug Monitoring Services for Patients on Anticonvulsants at Neurological Clinics in Ibadan, Oyo State, South West Nigeria

Therapeutic drug monitoring is an established pharmacokinetic tool used to optimize antiepileptic drug therapy by measuring serum drug concentrations and adjusting doses to achieve therapeutic targets while minimizing toxicity. In Nigerian neurological clinics, access to and utilization of therapeutic drug monitoring for anticonvulsant therapy management remain inadequately explored. This study evaluated the availability, utilization, and clinical outcomes associated with therapeutic drug monitoring services for patients on anticonvulsant therapy at neurological clinics in Ibadan, Oyo State, South West Nigeria. A mixed-methods cross-sectional study was conducted at three major tertiary hospitals, reviewing 220 patient case records and interviewing 20 neurologists, pharmacists, and laboratory scientists. Therapeutic drug monitoring was available in only one of three hospitals, and serum anticonvulsant level monitoring was performed in fewer than 15 percent of patients on phenytoin or carbamazepine in any facility. Among patients where monitoring had been performed, dose adjustments based on levels were made in only 58 percent. Pharmacists reported minimal involvement in interpreting serum level results or recommending dose modifications. Laboratory turnaround time exceeding 72 hours was identified as a practical barrier to therapeutic drug monitoring utilization. The study advocates for pharmacist-led therapeutic drug monitoring programs within neurological clinics, supported by rapid laboratory turnaround and standardized dosing protocols. Investment in therapeutic drug monitoring laboratory infrastructure across Ibadan teaching hospitals is recommended. Keywords: therapeutic drug monitoring, anticonvulsants, neurological clinic, Ibadan, clinical pharmacokinetics