A double-blind, randomized, multi-center, parallel-group study was conducted in Finland to compare the efficacy and safety of risperidone with zuclopenthixol in patients with acute exacerbations of schizophrenia or schizophreniform disorder. Ninety-eight patients were randomly assigned to treatment with risperidone (n = 48) or zuclopenthixol (n = 50), in variable doses, for 6 weeks. The mean daily doses of risperidone and zuclopenthixol at the end of the trial were 8 mg and 38 mg respectively. Efficacy was assessed throughout by the Positive and Negative Syndrome Scale for schizophrenia and Clinical Global Impression. Safety assessments included the Extrapyramidal Symptom Rating Scale, UKU Side-Effect Rating Scale, vital signs, body weight and laboratory screening. The results indicate that risperidone is at least as effective as zuclopenthixol for the treatment of acute schizophrenic episodes, with a trend towards greater improvement in the overall severity of symptoms. The onset of action was significantly shorter with risperidone than with zuclopenthixol. Although the general tolerability of the two drugs was comparable, fewer patients experienced extrapyramidal symptoms with risperidone, so that significantly fewer risperidone-treated patients required antiparkinsonian medication.
Influenza vaccination using conventional trivalent influenza vaccine does not affect serum concentrations of clozapine or its main metabolites. However, an infection-related increase in CRP may be associated with increased serum concentration of clozapine.
Clozapine and caffeine are metabolised mainly by the cytochrome P4501A2 (CYP1A2) enzyme. Studies suggest that caffeine in coffee inhibits clozapine metabolism and increases serum clozapine concentrations. Our objective was to study whether coffee in the amounts usually consumed has an effect on steady-state serum clozapine concentrations. A randomised placebo-controlled cross-over design with two phases was used. Twelve hospitalised clozapine-using patients volunteered in the study where, after one-week run-in period, either caffeine-containing or decaffeinated instant coffee was available ad libitum for seven days. Serum concentrations of clozapine, N-desmethylclozapine, clozapine-N-oxide, caffeine, paraxanthine and C-reactive protein were measured after run-in period and on days 4 and 8 of the following study phases. Two patients were excluded from the statistical analysis because of non-compliance based on serum caffeine and paraxanthine determinations. In six fully compliant patients caffeine-containing coffee increased the mean serum trough concentration of clozapine by 26% (non-significant (NS), 95% CI ª3% to π54%, PΩ0.07), N-desmethylclozapine by 6% (95% CI 1% to 12%, PΩ0.03), and clozapine-N-oxide by 7% (NS, 95% CI ª6% to π20%, PΩ0.22). The ratio of N-desmethylclozapine/clozapine decreased by 13% (NS, 95% CI ª1% to π27%, PΩ0.06) and that of clozapine-N-oxide/ clozapine by 7% (NS, 95% CI ª5% to π17%, PΩ0.19). In the analysis of combined data (including day 4 data of the four patients compliant up to that point) serum trough concentration of clozapine was 20% (95% CI 3% to 37% to PΩ 0.03) higher, and that of N-desmethylclozapine 7% (95% CI 2% to 13%, PΩ0.02) higher during the caffeine phase than during the decaffeinated phase. We conclude that the effect of instant coffee drinking on serum clozapine concentrations is of minor clinical relevance in most of the patients, but some individuals may be more sensitive to this interaction due e.g. to genetic factors. The increase in serum clozapine concentration was most likely due to the inhibition of the CYP1A2 enzyme by caffeine.
Clozapine and caffeine are metabolised mainly by the cytochrome P4501A2 (CYP1A2) enzyme. Studies suggest that caffeine in coffee inhibits clozapine metabolism and increases serum clozapine concentrations. Our objective was to study whether coffee in the amounts usually consumed has an effect on steady-state serum clozapine concentrations. A randomised placebo-controlled cross-over design with two phases was used. Twelve hospitalised clozapine-using patients volunteered in the study where, after one-week run-in period, either caffeine-containing or decaffeinated instant coffee was available ad libitum for seven days. Serum concentrations of clozapine, N-desmethylclozapine, clozapine-N-oxide, caffeine, paraxanthine and C-reactive protein were measured after run-in period and on days 4 and 8 of the following study phases. Two patients were excluded from the statistical analysis because of non-compliance based on serum caffeine and paraxanthine determinations. In six fully compliant patients caffeine-containing coffee increased the mean serum trough concentration of clozapine by 26% (non-significant (NS), 95% CI ª3% to π54%, PΩ0.07), N-desmethylclozapine by 6% (95% CI 1% to 12%, PΩ0.03), and clozapine-N-oxide by 7% (NS, 95% CI ª6% to π20%, PΩ0.22). The ratio of N-desmethylclozapine/clozapine decreased by 13% (NS, 95% CI ª1% to π27%, PΩ0.06) and that of clozapine-N-oxide/ clozapine by 7% (NS, 95% CI ª5% to π17%, PΩ0.19). In the analysis of combined data (including day 4 data of the four patients compliant up to that point) serum trough concentration of clozapine was 20% (95% CI 3% to 37% to PΩ 0.03) higher, and that of N-desmethylclozapine 7% (95% CI 2% to 13%, PΩ0.02) higher during the caffeine phase than during the decaffeinated phase. We conclude that the effect of instant coffee drinking on serum clozapine concentrations is of minor clinical relevance in most of the patients, but some individuals may be more sensitive to this interaction due e.g. to genetic factors. The increase in serum clozapine concentration was most likely due to the inhibition of the CYP1A2 enzyme by caffeine.
Carbamazepine was switched to its 10-keto analogue oxcarbazepine among six difficult-to-treat schizophrenic or organic psychotic patients using concomitantly haloperidol, chlorpromazine or clozapine. This change resulted within 2-4 weeks in the 50-200% increase in the plasma levels of these neuroleptics and the appearance of extrapyramidal symptoms. None of the patients showed any clinical deteriotation during the following 3-6 months. The results of this case report support the idea that in contrast with carbamazepine oxcarbazepine does not induce the hepatic microsomal enzyme systems regulating the inactivation of antipsychotic drugs.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.