Trial reportBritish journal of clinical pharmacology2004
Drug interaction between St John's Wort and quazepam.
Trial report in British journal of clinical pharmacology, 2004. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 9 papers, 2 of them syntheses 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
9 citing papers in PubMed, 2 syntheses or guidelines pooled it, 50 citations in OpenAlex.
- Interactions between herbal medicines and prescribed drugs: an updated systematic review.Drugs · 2009Pooled it
- The effect of St John's wort extracts on CYP3A: a systematic review of prospective clinical trials.British journal of clinical pharmacology · 2006Pooled it
- Influence ofPharmacogenomics and personalized medicine · 2018Article
- Article
- Drug interactions with herbal medicines.Clinical pharmacokinetics · 2012Review
- Herb-drug interactions with St John's wort (Hypericum perforatum): an update on clinical observations.The AAPS journal · 2009Review
- The recovery time-course of CYP3A after induction by St John's wort administration.British journal of clinical pharmacology · 2008Article
- Herb-drug interactions: a literature review.Drugs · 2005Review
- Phytochemicals That Interfere With Drug Metabolism and Transport, Modifying Plasma Concentration in Humans and Animals.Dose-response : a publication of International Hormesis SocietyReview
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
10 authors at 2 institutions in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
aimSt John's Wort (SJW) enhances CYP3A4 activity and decreases blood concentrations of CYP3A4 substrates. In this study, the effects of SJW on a benzodiazepine hypnotic, quazepam, which is metabolized by CYP3A4, were examined.
methodsThirteen healthy subjects took a single dose of quazepam 15 mg after treatment with SJW (900 mg day(-1)) or placebo for 14 days. The study was performed in a randomized, placebo-controlled, cross-over design with an interval of 4 weeks between the two treatments. Blood samples were obtained during a 48 h period and urine was collected for 24 h after each dose of quazepam. Pharmacodynamic effects were determined using visual analogue scales (VAS) and the digit symbol substitution test (DSST) on days 13 and 14.
resultsSJW decreased the plasma quazepam concentration. The Cmax and AUC(0-48) of quazepam after SJW were significantly lower than those after placebo [Cmax; -8.7 ng ml(-1) (95% confidence interval (CI) -17.1 to -0.2), AUC0-48; -55 ng h ml(-1) (95% CI -96 to -15)]. The urinary ratio of 6beta-hydroxycortisol to cortisol, which reflects CYP3A4 activity, also increased after dosing with SJW (ratio; 2.1 (95%CI 0.85-3.4)). Quazepam, but not SJW, produced sedative-like effects in the VAS test (drowsiness; P < 0.01, mental slowness; P < 0.01, calmness; P < 0.05, discontentment; P < 0.01). On the other hand, SJW, but not quazepam impaired psychomotor performance in the DSST test. SJW did not influence the pharmacodynamic profile of quazepam.
conclusionsThese results suggest that SJW decreases plasma quazepam concentrations, probably by enhancing CYP3A4 activity, but does not influence the pharmacodynamic effects of the drug.
Indexed as
Identifiers
What OpenQuestion holds
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.