Andrew Menelaou

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OBJECTIVE To determine plasma racemic methadone concentration-effect relationships for subjective and objective responses and whether pharmacokinetic and/or pharmacodynamic factors influence withdrawal severity. METHODS Eighteen patients enrolled in a public methadone maintenance program, nine of whom experienced significant withdrawal, received constant(More)
The individual cytochrome P450 isoforms in dextropropoxyphene N-demethylation to nordextropropoxyphene were determined and the pharmacokinetics of dextropropoxyphene and nordextropropoxyphene in cytochrome P4502D6 (CYP2D6) extensive (EM) and poor (PM) subjects were characterized. Microsomes from six CYP2D6 extensive metabolizers and one CYP2D6 poor(More)
A simple, robust HPLC method was developed to measure simultaneously the plasma concentrations of amoxycillin and metronidazole in order to assess their disposition in the eradication of Helicobacter pylori. Plasma samples were protein precipitated, pH adjusted and the supernatant injected onto the HPLC system which used a C18 column, paired-ion aqueous(More)
AIM To determine the Michaelis-Menten kinetics of hydrocodone metabolism to its O- and N-demethylated products, hydromorphone and norhydrocodone, to determine the individual cytochrome p450 enzymes involved, and to predict the in vivo hepatic intrinsic clearance of hydrocodone via these pathways. METHODS Liver microsomes from six CYP2D6 extensive(More)
We have previously shown that methadone maintenance patients are hyperalgesic. Very little is known about the antinociceptive effects of additional opioids in these patients. This study (1) compared the intensity and duration of antinociceptive responses, at two pseudo-steady-state plasma morphine concentrations (C(SS1) and C(SS2)), between four patients on(More)
High-performance liquid chromatographic assays for the O- and N-demethylated oxidative metabolites of hydrocodone and oxycodone formed in human liver microsomes are described. A solvent-solvent extraction/re-extraction procedure followed by reversed-phase HPLC with UV detection at 210 nm allows for the quantification of hydromorphone, norhydrocodone,(More)
OBJECTIVE The aims of this study were to determine the effects of the CYP2C8*3 and *4 polymorphisms on imatinib metabolism and plasma imatinib concentrations in chronic myeloid leukaemia (CML) patients. METHODS We genotyped 210 CML patients from the TIDELII trial receiving imatinib 400-800 mg/day for CYP2C8*3 (rs11572080, rs10509681) and *4 (rs1058930).(More)
Although methadone maintenance is designed to stabilize opioid-dependent patients, some experience significant withdrawal in the latter part of the 24-hour interdosing interval. This study was designed to determine the mood changes that maybe associated with such withdrawal. Eighteen methadone patients, nine of whom experienced significant withdrawal, were(More)
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