Drug | Residual concentration at time of sampling (ng/mL) Ct | Mean half-life (h) t1/2 | Elimination constant k = log(2)/t1/2 | Initial concentration 48 h prior to sampling (ng/mL) C0 = Ct/e−kt | Blood concentration from database (ng/mL) |
Lormetazepam | 6.8 | 10 [16] | 0.693/10 = 0.0693 | 6.8/e−(0.0693)48 6.8/0.036 = 189 | Therapeutic: 2 - 10 [12] Toxic: 100 [12] |
Lorazepam | 6.3 | 14 [17] | 0.693/14 = 0.0495 | 6.3/e−(0.0495)48 6.3/0.093 = 68 | Therapeutic: 20 - 250 [12] Toxic: 300 - 500 [12] |
Nordiazepam | 16.2 | 65 [11] | 0.693/65 = 0.0106 | 16.2/e−(0.0106)48 16.2/0.6 = 27 | Therapeutic: 200 - 800 [12] Toxic: 1500 - 2000 [12] |
Oxazepam | Assumed to be 1.0 (limit of quantification) | 8 [13] | 0.693/8 = 0.0866 | 1.0/e−(0.0866)48 1.0/0.0156 = 64 | Therapeutic: 200 - 1500 [12] Toxic: 2000 [12] |