Evidence-based Implementation of Free Phenytoin Therapeutic Drug Monitoring

Evidence-based implementation of free phenytoin therapeutic drug monitoring.

BACKGROUND The majority of laboratories measure total phenytoin concentration for therapeutic drug monitoring. However, there are substantial interindividual variations in free phenytoin concentrations, the pharmacologically active component. METHODS We describe the process and data used to implement monitoring of free phenytoin only in an urban medical center. Over a 6-week period, total and...

Clinical decision support of therapeutic drug monitoring of phenytoin: measured versus adjusted phenytoin plasma concentrations

BACKGROUND Therapeutic drug monitoring of phenytoin by measurement of plasma concentrations is often employed to optimize clinical efficacy while avoiding adverse effects. This is most commonly accomplished by measurement of total phenytoin plasma concentrations. However, total phenytoin levels can be misleading in patients with factors such as low plasma albumin that alter the free (unbound) c...

Influence of aging on serum phenytoin concentrations: a pharmacokinetic analysis based on therapeutic drug monitoring data.

The influence of aging on the pharmacokinetics of phenytoin at steady-state was evaluated retrospectically by comparing apparent oral clearance values (CL/F) in 75 patients aged 65-90 years (mean, 71.7 +/- 5.3 years) receiving phenytoin alone (n = 58) or in combination with phenobarbital (n = 17) and in an equal number of control patients aged 20-50 years (mean, 36.7 +/- 8.5 years) matched for ...

ABC of monitoring drug therapy. Phenytoin.

A Review on Therapeutic Drug Monitoring of Immunosuppressant Drugs

Immunosuppressants require therapeutic drug monitoring because of their narrow therapeutic index and significant inter-individual variability in blood concentrations. This variability can be because of factors like drug-nutrient interactions, drug-disease interactions, renal-insufficiency, inflammation and infection, gender, age, polymorphism and liver mass. Drug monitoring is widely practiced ...