Primidone

Specimen:

5 mL blood in plain tube.

Method:

Chromatography or immunoassay.

Therapeutic Interval:

22-50 µmol/L (4.8-11.0 mg/L).

Application:

Therapeutic drug monitoring.

Interpretation:

Phenobarbitone is an active metabolite of primidone and the level of phenobarbitone is often measured as well as, or instead of, primidone. Steady state level of primidone is reached after 48 h. Mean half-life 10 h (range 3-20 h).

Reference:

Cloyd JC et al. Clin Pharmacol Ther 1981; 29: 402-407.