Moving toward Personalized Medicine in the Methadone Maintenance Treatment Program: A Pilot Study on the Evaluation of Treatment Responses in Taiwan

Table 4

Influence of ABCB1 polymorphism on methadone plasma concentrations in responders and nonresponders (𝑛=176)^a.

ABCB1 genotype	𝑛 (%)	Dose (SD)	R,S-Methadone^b(SD)	R-Methadone^b(SD)	S-Methadone^b(SD)
Responders (𝑛=61)
G2677T
G/G	22 (36.1)	47.6 (31.4)	5.20 (0.98)	4.09 (0.83)	3.95 (0.76)
G/T	21 (34.4)	61.3 (29.8)	5.00 (0.72)	4.15 (0.51)	3.93 (0.61)
T/T	18 (29.5)	47.1 (30.1)	5.97 (0.71)	4.72 (0.72)	4.55 (0.75)
𝑃 value	—	0.24	0.001*	0.01*	0.01*

aNo available data on genotype for two subjects due to methodological problems.
^bR,S-Methadone, R-methadone, and S-methadone plasma concentrations were divided by the methadone dose (in milligrams per day) and by the patient weight (in kilograms). The unit of concentration is ng·kg/mL·mg. Then, the values were natural log transformed before analysis. All values are expressed as the mean and standard deviation (SD).
*Statistical significance set at 𝑃<0.05; comparisons were performed by the ANOVA or Kruskal-Wallis test as appropriate.