Table 5.

Comparative studies highlighting clinical benefits of performing therapeutic drug monitoring for gentamicin, voriconazole and ribavirin

Study/country/population	Patients	Study design	Clinical outcomesa	TDM	Non-TDM
Van Lent-Evers (1999)	Total: 232	Multi-centre, non-randomised, before-and-after trial	Dose changes (%)*	48.6	80.4
Netherlands	TDM: 105	TDM: Bayesian-guided dosing	Duration of therapy (days)*	5.9 ± 2.9	8.0 ± 4.9
Gentamicin	Non-TDM: 127	Non-TDM: standard or nomogram	Length of stay (days)*	20.0 ± 13.7	26.3 ± 31.5
Gram-negative sepsis			Mortality (%) Nephrotoxicity (%)* Total costs (in DFL)*	9 (8.6%) 3 (2.8) 13,125 ± 9,267	18 (14.2) 17 (13.4) 16,862 ± 17,721
Park (2012)	Total: 110	Single-centre, assessor-blinded, randomised controlled trial	Adverse events (%)	23 (42)	22 (42)b
South Korea	TDM: 55	TDM: concentration-controlledc	Drug discontinuation (%)*	2 (4)	9 (17)b
Voriconazole	Non-TDM: 55	Non-TDM: standard therapy	Treatment response (%)*,d	30 (81)e	20 (59)f
Invasive fungal infections
Stickel (2013)g	Total: 16	Multi-centre, open-labelled, randomised controlled trial	Sustained virological response (%)h	10 (62.5)	6 (37.3)
Switzerland	TDM: 16	TDM: concentration-controlledi	Mean haemoglobin (g/L)*	99.6	106.3
Ribavirin	Non-TDM: 16	Non-TDM: weight-based dosing
Chronic hepatitis C

DFL = Dutch florin, i.e. the currency of Netherlands up to 2002; TDM = therapeutic drug monitoring

^aAn asterisk indicates a significant difference between TDM and non-TDM groups

^bOnly 53 patients were included

^cTarget trough concentration of 1.0–5.5 mg/L

^dIncluded either complete or partial response

^eOnly 37 patients were included

^fOnly 34 patients were included

^gReported in a research letter

^hCumulative ribavirin exposure above 224.3 mg/L was significantly associated with sustained virological response

ⁱTarget concentration of 3.7 mg/L