Pharmacokinetics of tramadol after subcutaneous administration in a critically ill population and in a healthy cohort

Table 2 Pharmacokinetic parameters

Parameter/ units	Healthy subjects mean (SD), (n = 8)	Patients mean (SD), (n = 15)	p value	Differences between patients and healthy subjects
				Mean	Standard error
C _max (mcg/ml)	0.47 (0.13)	0.44 (0.18)	0.67	-0.032	0.073
AUC _∞ *(mcg/mlmin)**	175 (75)	177 (109)	0.96	2.07	43.6
t½ (min)	310 (147)	306 (164)	0.96	-3.5	69.6
t _max (min)	20.6 (18.8)	23.3 (17.1)	0.73	2.7	7.7
MRT (min)	466 (224)	463 (233)	0.97	-3.4	100.8

All eight healthy subjects and 15 patients received 50 mg tramadol as a subcutaneous bolus injection. The p-value is for a One Factor ANOVA comparing the cohorts. The mean difference between the patient and healthy groups is shown with its standard error as an indicator of study power.
*represents the unit of AUC as in product of ml and min.

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