. Author manuscript; available in PMC: 2009 Nov 12.

Published in final edited form as: Eur J Pharmacol. 2008 Aug 30;597(1-3):39–45. doi: 10.1016/j.ejphar.2008.08.025

Table 3.

Tolerance following treatment with hydromorphone

Infusion		Injection
			Shift in ED_{50 (±SEM)}
(Multiple of ED₅₀)	Shift in ED_{50 (±se)}	(Multiple of ED₅₀)	1 Day	7 Days
10	3.0 ^a (± 0.8)	10	1.6 (± 0.1)	1.2 (± 0.1)
50	6.3 ^a (± 0.8)	50	1.8 (±0.2)	1.9 (± 0.5)
100	13.7 ^a (± 0.9)	100	1.5 (±0.3)	2.9 ^a (± 0.6)
150	24.1 ^a (± 0.8)

Estimation of morphine tolerance following 7 day continuous infusion (left), and 1 or 7 day injections (right) with hydromorphone. At the end of hydromorphone treatment, morphine cumulative dose response studies were performed (see methods). Infusion studies present the shift in the ED₅₀ (±se from Probit analysis) and are from a single determination, except for 100 times the ED₅₀, which is the combined data from two experiments. Intermittent studies were repeated three times and the mean (± S.E.M.) is presented.

significantly different from 1.0 (P< 0.05).