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Table 1 Calculation formulas to estimate blood pregabalin kinetics and clearances

From: High-flow continuous hemodiafiltration successfully decreased blood pregabalin levels in a patient with severe pregabalin intoxication: a case report

Calculating formula

Elimination rate constant (hour−1)

K_Pt =  − (lnC0 − lnC2.5)/(T0 − T2.5)

K_Pt+CHDF =  − (lnC2.5 − lnC3.5)/(T2.5 − T3.5)

Half-life time (hours)

t_Pt = 0.693/ K_Pt

t_Pt+CHDF = 0.693/ K_Pt+CHDF

Clearance (mL/min)

CL_Pt = Vd/F × K_Pt × 1000/60

CL_CHDF = (CBi − CBO)/CBi × (QB − QF/60) + QF/60

Estimated serum level (μg/mL)

eCx = C2.5 × (1/2)^[(Tx − 2.5)/t_Pt+CHDF]

  1. K_Pt, elimination rate constant depends on the patient’s metabolism; K_Pt+CHDF, elimination rate constant during performing continuous hemodiafiltration; Cx, actual serum pregabalin level X hours after the hospital arrival; TX, elapsed time after the hospital arrival; t_Pt, pregabalin half-life time depends on the patient’s metabolism; t_Pt+CHDF, pregabalin half-life time during performing continuous hemodiafiltration; CL_Pt, patient’s metabolic pregabalin clearance; Vd/F, volume of distribution (assumed as 36 L in this case); CL_CHDF, continuous hemodiafiltration’s pregabalin clearance; CBi, serum pregabalin level at the hemofilter inlet (serum pregabalin level at 7.5 h was assumed as CBi in this case); CBo, serum pregabalin level at the hemofilter outlet; QB, blood flow rate (mL/min); QF, blood filtration rate (mL/h); eCX, estimated serum pregabalin level X hours after the hospital arrival