ArticleJournal of research in pharmacy practice
Influence of Cigarette Smoking Habit on Clozapine-to-Norclozapine Ratio in Male Patients.
Article in Journal of research in pharmacy practice. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 3 papers, 1 of them a synthesis that pooled it.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
3 citing papers in PubMed, 1 synthesis or guideline pooled it, 3 citations in OpenAlex.
- Influence of cigarette smoking on drugs' metabolism and effects: a systematic review.European journal of clinical pharmacology · 2025Pooled it
- Predictors of clozapine concentration and psychiatric symptoms in patients with schizophrenia.PloS one · 2025Article
- The effects of clinical and pharmacological factors on the ratio of clozapine to norclozapine in psychiatric patients.Frontiers in pharmacology · 2024Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
2 authors at 2 institutions in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
Objective: This study aimed to evaluate the influence of cigarette smoking habit on the clozapine (CLZ)-to-norclozapine (norCLZ) ratio in male patients. Methods: The sample consisted of plasma concentration of CLZ and norCLZ data set. The mean values of CLZ, norCLZ, and CLZ-to-norCLZ, between male patients who smoke versus nonsmokers were compared. Findings: CLZ mean plasma level of 142 ± 80 ng/ml and 305 ± 159 ng/ml, norCLZ mean plasma level of 93 ± 72 ng/ml and 234 ± 62 ng/ml, and mean CLZ-to-norCLZ plasma level ratio of 2.1 ± 1.1 and 1.5 ± 0.5, were obtained respectively for male patients who smoke and nonsmokers. Conclusion: This study has shown a significant decrease in CLZ and norCLZ plasma levels, and an increase in the CLZ-to-norCLZ ratio, in smokers as compared to nonsmokers, due to an increase in the clearance of CLZ and norCLZ by smoking induction of CYP 1A2 and glucuronidation by uridyl glucuronyl transferase enzymes (UGT), mainly UGT 1A4, respectively, as the most probable cause.
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.