Possible Interaction: Morphine and Quinine

“Keto derivatives of cholic acid, such as 3a, 7a, dihydroxy-12-keto-5a-cholic acid (sodium salt … methyl ester) are potential modifiers of blood-brain barrier transport and have been shown to promote quinine up-take, enhance … analgesic effect of morphine and prolong the sleeping time induced by pentobarbital.”

“However, the value of using quinine solutions to control for effects due to the bitter taste of morphine was more limited than has sometimes been supposed; the relative palatabilities of the two drugs seemed to vary across experiments.”

“Thus, quinine is effective to drive morphine consumption and engender dependence but may confound the ability to measure oral abuse liability of morphine.”

“Independent groups of mice of the same strains were exposed to quinine in a parallel manner to control for the bitter alkaloid taste of morphine.”

“Furthermore, quinine at a lower dose (25 mg/kg) that showed no per se effect on gastrointestinal transit, significantly potentiated the response to 2.5 mg/kg morphine.”

“In addition, when tested in the absence of morphine, rats displayed a reduced aversion to quinine, suggesting that quinine became conditionally less aversive following previous pairings with morphine.”

“ Morphine pretreatment attenuates aversive taste reactions elicited by quinine solution when assessed by the taste reactivity test.”

“The results suggest that amphetamine, like morphine , attenuates the aversiveness of the taste of quinine solution.”

“ Morphine reduced the aversive hedonic properties of both novel and familiar quinine solution (0.05% and 0.1%) but did not modify the palatability of 20% sucrose solution.”

“KCN (10(-2) M), mepiperphenidol (Darstine, 10(-4) M) and quinine (10(-4) M) inhibited [3H]morphine uptake by 55-70%.”

“Narcotic antagonists and analogs (methadone, nalorphine and levorphanol) and quinine also reduced the uptake of morphine from medium levels of 0.01 to 0.1 μM. However, at morphine concentrations above 10 μM, narcotic analogs or antagonists up to 50 μM did not inhibit uptake.”