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. Author manuscript; available in PMC: 2009 Apr 14.
Published in final edited form as: Pain. 2008 Apr 9;139(1):5–14. doi: 10.1016/j.pain.2008.02.023

Fig. 2.

Fig. 2

Median effective doses (ED50) of intrathecal fentanyl according to genotype using sequential allocation (SA). Data show effective (success) and ineffective (failure) analgesic outcomes for wild-types (Group A) and women carrying one or more 304G allele (Group G) with solid bars representing ED50 and dotted bars representing 95% confidence intervals (95% CI). (A) Using up-down analysis, ED50 was 26.8 μg (95% CI 22.7–30.9) in women 304A homozygotes (per-protocol analysis, n = 25). (B) Using up-down analysis, ED50 was 17.7 μg (95% CI 13.4–21.9) in women carrying at least one 304G allele (per-protocol analysis, n = 19), ED50 ratio (A:G) for genotype is 1.51 (95% CI 1.18–2.01), p = 0.009.