Metabolism of levomepromazine in man

Levomepromazine for schizophrenia

BACKGROUND

Levomepromazine is an 'older' typical antipsychotic medication licensed for use in schizophrenia but sparingly prescribed in the United Kingdom.

OBJECTIVES

To determine the clinical effects and safety of levomepromazine compared with placebo or antipsychotic medications for schizophrenia and schizophreniform psychoses.

SEARCH STRATEGY

We searched the Cochrane Schizophrenia Group's Register (December 2008) which is based on regular searches of, amongst others, BIOSIS, CENTRAL CINAHL, EMBASE, MEDLINE and PsycINFO. References of all identified studies were inspected for further trials. We also contacted relevant pharmaceutical companies for additional information.

SELECTION CRITERIA

All randomised trials comparing levomepromazine with placebo or other antipsychotics for schizophrenia and schizophreniform psychoses were included.

DATA COLLECTION AND ANALYSIS

Data were extracted independently. For dichotomous outcomes, we calculated relative risk (RR) (random-effects model), 95% confidence intervals (CI) and, where appropriate, number needed to treat (NNT) was calculated. We avoided the use of number needed to harm (NNH), as an alternative we used number needed to treat for an additional beneficial outcome (NNTB) and number needed to treat for an additional harmful outcome (NNTH) to indicate the direction of effect. For continuous outcomes, we calculated weighted mean differences (WMD).

MAIN RESULTS

The review currently includes 4 RCTs with 192 participants. For our primary outcome of leaving the study early, levomepromazine was not significantly different compared with other antipsychotics. The levomepromazine arm was significantly better on CGI severity compared with chlorpromazine (n=38, 1 RCT, WMD -0.80 CI -1.51 to -0.09). Risperidone was better for CGI endpoint scores (n=42, 1 RCT, RR 2.33 CI 1.11 to 4.89, NNT 3 CI 2 to 10) compared with levomepromazine. Recipients given levomepromazine had a better BPRS endpoint score (n=38, 1 RCT, WMD -9.00, CI -17.46 to -0.54) and PANSS total score (n=38, 1 RCT, WMD -15.90, CI -30.30 to -1.50) than chlorpromazine. Risperidone recipients noticed a significant difference for the outcome 'at least 20% reduction' on BPRS endpoint score (n=42, 1 RCT, RR 3.33 CI 1.07 to 10.42, NNT 3 CI 2 to 14) compared with levomepromazine. Levomepromazine caused less tremor (n=41, 1 RCT RR 0.12 CI 0.02 to 0.87 NNTB 3 CI 2 to 8), less antiparkinsonian medication administration (n=79, 2 RCTs, RR 0.39 CI 0.17 to 0.90, NNTB 5, CI 2 to 21) compared with haloperidol. Levomepromazine caused less akathisia compared with chlorpromazine, but more hypotension compared with risperidone (n=42, 1 RCT, RR 2.50 CI 1.21 to 5.18, NNTH 3, CI 2 to 7). Dizziness was common with levomepromazine compared with other antipsychotic medications.

AUTHORS' CONCLUSIONS

Available data does not enable us to confidently comment on the effectiveness of levomepromazine for schizophrenia. Larger, more robust, studies comparing levomepromazine with other antipsychotics including clozapine are much needed.

Comparative study between target-controlled-infusion and continuous-infusion anesthesia in dogs treated with methotrimeprazine and treated with propofol and remifentanil

PURPOSE: To compare two propofol infusion techniques in bitches subjected to ovaryhisterectomy by estimating the efficiency of the propofol target-dose, evaluating the cardiorespiratory and hemogasimetric attributes, and the bispectral scale index (BIS) as well as the recovery period characteristics. METHODS: Twenty anesthetized bitches were divided into two groups of 10 each (G1, G2). Animals of G1 were pre-treated with methotrimeprazine and anesthetized with target-controlled propofol infusion by means of a Harvard infusion pump combined to remifentanil through a syringe pump. RESULTS: Bradycardia and light hypotension, hemogasimetric and respiratory stability besides a good myorelaxation, more evident during continuous infusion and good hypnosis. CONCLUSIONS: Dosis used in both techniques, after methotrimeprazine pre-treatment and combined to the opioid, were efficient for the surgery. The target-controlled anesthesia required a smaller anesthetic consumption (propofol) with faster recovery periods.

Comparative study of the sedative and antinociceptive effects of levomepromazine, azaperone and midazolam in laboratory animals

The sedative and antinociceptive effects of levomepromazine, azaperone and midazolam were studied in rats and mice using three behavior evaluation methods. Both exploratory behavior and spontaneous locomotor activity were significantly diminished in a spontaneous locomotor activity test in open field when using levomepromazine and azaperone. However, the azaperone effects were short lived in comparison to levomepromazine effects. Midazolam caused reduction in exploratory activity with no effect in spontaneous locomotion. When assessing the antinociceptive effect in the tail flick reflex latency test after infliction of a pain stimulus in rats, tested drugs did not show any antinociceptive effect. The drugs studied were able to abolish the writhing reflex in mice when compared to control. Levomepromazine, azaperone and midazolam, at the doses were able to inhibit the exploratory behavior in rats, proving their sedative effect. Regarding the antinociceptive effects for visceral pain, these drugs were able to block contortions in mice.

Simultaneous determination of levomepromazine, midazolam and their major metabolites in human plasma by reversed-phase liquid chromatography

A sensitive and reliable high-performance liquid chromatographic (HPLC) assay is a prerequisite for pharmacokinetic analysis of continuous infusion of levomepromazine adjuvant to midazolam. We developed such a method to determine the levels of levomepromazine, midazolam and their major metabolites (levomepromazinesulfoxide, desmethyl-, didesmethyllevomepromazine, O-desmethyllevomepromazine and alpha-hydroxy-midazolam) simultaneously. Desmethylclomipramine was used as an internal standard (I.S.). The lower limit of quantification of this assay was set for levomepromazine 4.1 microg/l, levomepromazinesulfoxide 4.9 microg/l, O-desmethyllevomepromazine 18.4 microg/l, alpha-hydroxymidazolam 26.6 microg/l, midazolam 23.4 microg/l, didesmethyllevomepromazine 15.8 microg/l, and desmethyllevomepromazine 6.6 microg/l. The between- and within day assay variations were commonly below 5%. The recovery in human plasma for the different analytes varied between 85 and 11%. The accuracy of this assay varied between 95 and 105% for the different concentrations. The linearity of this assay was set between 25 and 800 microg/l (r(2)>0.999 of the regression line). The first results of pharmacokinetic analysis of midazolam indicated that half-life varied between 1.1 and 1.9 h. Pharmacokinetic analysis using a one-compartment model of levomepromazine revealed that the apparent volume of distribution was 4.1+/-2.4 l per kg lean body mass and the metabolic clearance was 309+/-225 l per hour per 70 kg. This assay proved to be robust and reproducible. It can reliably be used for further study of the pharmacokinetics of continuous infusion of levomepromazine.

Determination of phenothiazines in human body fluids by solid-phase microextraction and liquid chromatography/tandem mass spectrometry

Eleven phenothiazine derivatives with heavy side-chains were found to be extractable from human whole blood and urine samples by solid-phase microextraction (SPME) with a polyacrylate-coated fiber. The fiber was then injected into the desorption chamber of an SPME-liquid chromatography (LC) interface for LC/tandem mass spectrometry (MS/MS) with positive ion electrospray (ES) ionization. All compounds formed base peaks due to [M + 1](+) ions by LC/ES-MS/MS. By use of LC/ES-MS/MS, the product ions produced from each [M + 1](+) ion showed base peaks due to side-chain liberation. Selected reaction monitoring (SRM) and selected ion monitoring (SIM) were compared for the detection of the 11 phenothiazine derivatives from human whole blood and urine. SRM showed much higher sensitivity than SIM for both types of sample. Therefore, a detailed procedure for the detection of drugs by SRM with SPME-LC/MS/MS was established and carefully validated. The extraction efficiencies of the 11 phenothiazine derivatives spiked into whole blood and urine were 0. 0002-0.12 and 2.6-39.8%, respectively. The regression equations for the 11 phenothiazine derivatives showed excellent linearity with detection limits of 0.2-200 ng ml(-1) for whole blood and 4-22 pg ml(-1) for urine. The intra- and inter-day precisions for whole blood and urine samples were not greater than 15.1%. The data obtained after oral administration of perazine or flupentixol to a male subject are presented.