Drug interaction between St John's Wort and quazepam

AIM: St 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. METHODS: Thirteen 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. RESULTS: SJW 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. CONCLUSIONS: These results suggest that SJW decreases plasma quazepam concentrations, probably by enhancing CYP3A4 activity, but does not influence the pharmacodynamic effects of the drug.     

Drug interactions with St. John's Wort (Hypericum perforatum): a review of the clinical evidence

St. John's Wort (SJW, Hypericum perforatum) is effective in mild-to-moderate depression. As a monotherapy, SJW has an encouraging safety profile. However, numerous reports indicate the possibility of important interactions with prescribed drugs. SJW has been shown to lower the plasma concentration (and/or the pharmacological effect) of a number of drugs including alprazolam, amitriptyline, cyclosporine, digoxin, fexofenadine, indinavir, irinotecan, methadone, nevirapine, simvastatin, tacrolimus, theophylline, warfarin, phenprocoumon and oral contraceptives. Induction of P-glycoprotein and/or cytochrome P450 (CYP) enzymes (particularly CYP 3A4) by SJW could explain such pharmacokinetic interactions. When combined with serotonin reuptake inhibitor, antidepressants (e.g. sertaline, paroxetine, nefazodone) or buspirone, SJW can cause serotonergic syndrome. SJW represents a herbal medicine with a high potential for drug interactions. Some of such interactions may have serious clinical consequences.     

Consultation and survey for drug interaction in outpatients taking the medicines potentially interact with St. John's Wort

Ministry Health Welfare of Japan announced the caution for drug interaction of St. John's Wort (SJW), a herbal supplement occasionally used for depression, on May, 2000. Immediately after the announcement, we conducted drug consultation for outpatients prescribed the medicines potentially interacting with SJW. We provided information concerning possible drug interaction with SJW for 741 outpatients (except for pediatrics) during the period of May 22-June 16, 2000. The potential drugs prescribed frequently were warfarin (28.0%), theophylline (19.7%), digitalis (18.4%), carbamazepine (7.2%), disopyramide (6.9%) and cyclosporin (6.3%). Of the patients, 401 subjects were surveyed by collecting the questionnaires to clarify the background of SJW drug interaction. Twenty-two subjects (5.5%) have known commercially available SJW products, 5 subjects (1.2%) have ever taken SJW products before and 2 subjects (0.5%) have taken SJW products concomitant with prescribed medicines. Gender difference was observed in paying attention to SJW products; female subjects (8.6%) tended to have more interest in SJW products than male subjects (2.8%). Two subjects taking SJW have realized for the first time that the supplements they took were SJW products when their package photographs were shown at the consultation. Showing the package photographs might be helpful for making the patients easy to identify the SJW products, because most patients do not pay attention to whether the supplements contain SJW or not. It is recommended that drug consultation should be provided to avoid serious drug interaction with SJW while the outpatients are taking potential medicines prescribed.     

Lack of interaction between orlistat and oral contraceptives

Objectives: Orlistat, a potent and selective inhibitor of gastrointestinal lipases, is designed for the treatment of obesity. A double-blind, randomised, placebo-controlled, 2-way crossover study investigated the possible influence of orlistat on the ovulation-suppressing action of combination oral contraceptives (OC). Methods: After an 8-day run-in prior to the first of two consecutive menstrual cycles (Day 1 was the first day of menstruation), two groups of 10 healthy women, 20–27 years of age and on a stable regimen with OCs, received either 120 mg orlistat t.i.d. or placebo t.i.d. on Days 1–23 of the first cycle, and, separated by a placebo washout period on Days 24–28, the alternative treatment on Days 1–23 of the second cycle. In both cycles, serum luteinizing hormone (LH) was measured on Days 12–16 and progesterone on Days 12, 16, 19–23. Results: The geometric means of time-averaged concentrations (Days 12–16 for LH and Days 19–23 for progesterone) in the cycles with orlistat and placebo, respectively, and the one-sided 95% confidence region for the mean in the cycle with orlistat were 1.92, 2.03 and < 2.23 IU l⁻¹ for LH and 0.147, 0.145 and < 0.176 μg l⁻¹ for progesterone. The one-sided 95% confidence region for the ratio (orlistat/placebo) of geometric means was < 1.06 for LH and < 1.11 for progesterone. Conclusion: During normal ovulation the peak serum concentration of LH is above 30 IU l⁻¹ around Day 14 of the cycle, and that of progesterone exceeds 3 μg l⁻¹ around day 21. The 95% confidence regions for the means, as well as all individual concentrations, were below these limits. It was concluded that orlistat did not influence the ovulation suppressing action of oral contraceptives. Received: 18 April 1995/Accepted in received form: 6 November 1995     

Pharmacokinetic modelling of the interaction between St John's wort and ciclosporin A

AIMS: St John's wort (SJW) decreases the blood concentration of ciclosporin A (CsA), which may result in allograft rejection. In addition, the time course of this interaction is not parallel with the administration of SJW. We aimed to develop a pharmacokinetic model to predict the time profile of blood CsA concentrations during and after the intake of SJW. METHODS: We developed a pharmacokinetic model incorporating turnover of detoxicating proteins, with the assumption that the amount of detoxicating proteins is in inverse proportion to the ratio of trough blood concentration to daily dose (C/D ratio) of CsA. First, we collected time profiles of blood CsA during and after the intake of SJW from the literature. Next, we analysed the relationship between D/C ratio and the daily dose of SJW at steady state. Subsequently, the developed model was simultaneously fitted to the time profiles of C/D ratios by using a nonlinear least-squares method to obtain model parameters. RESULTS: The model analysis revealed that the induction of the detoxicating proteins by SJW was saturable with an elimination rate constant of the detoxicating proteins (ke) of 4.72 month(-1). Elimination half-life of the detoxicating proteins calculated from the ke value was 4.4 days, suggesting that the dose of CsA should be carefully monitored for up to 2 weeks after the cessation of SJW intake. CONCLUSIONS: The present model may provide additional information for use in identifying optimal dosage regimens of CsA during and after the intake of SJW to prevent an adverse drug interaction between CsA and SJW.     

Extracting Lipophilic Biologically Active Substances from the Grass of St. John's Wort with Water – Oil Emulsions

Pharmaceutical Chemistry Journal -     

Metabolome classification of commercial Hypericum perforatum (St. John's Wort) preparations via UPLC-qTOF-MS and chemometrics

The growing interest in the efficacy of phytomedicines and herbal supplements but also the increase in legal requirements for safety and reliable contents of active principles drive the development of analytical methods for the quality control of complex, multicomponent mixtures as found in plant extracts of value for the pharmaceutical industry. Here, we describe an ultra-performance liquid chromatography method (UPLC) coupled with quadrupole time of flight mass spectrometry (qTOF-MS) measurements for the large scale analysis of H. perforatum plant material and its commercial preparations. Under optimized conditions, we were able to simultaneously quantify and identify 21 metabolites including 4 hyperforins, 3 catechins, 3 naphthodianthrones, 5 flavonoids, 3 fatty acids, and a phenolic acid. Principal component analysis (PCA) was used to ensure good analytical rigorousness and define both similarities and differences among Hypericum samples. A selection of batches from 9 commercially available H. perforatum products available on the German and Egyptian markets showed variable quality, particularly in hyperforins and fatty acid content. PCA analysis was able to discriminate between various preparations according to their global composition, including differentiation between various batches from the same supplier. To the best of our knowledge, this study provides the first approach utilizing UPLC-MS-based metabolic fingerprinting to reveal secondary metabolite compositional differences in Hypericum extract.     

Photogenotoxicity of hypericin in HaCaT keratinocytes: implications for St. John's Wort supplements and high dose UVA-1 therapy

Extract of St. John's Wort (Hypericum perforatum) is commonly used as natural remedy for treatment of mild to moderate depression. However, it contains a powerful photoactive component, hypericin, which can cause a severe photodermatitis when eaten by grazing animals (hypericism). In humans, there is evidence that supplementation with St. John's Wort can reduce the minimal erythemal dose (MED) in patients undergoing high dose UVA-1 phototherapy. This is a recent development in phototherapy where the most erythemogenic parts of the UVA spectrum are filtered out, allowing delivery of higher doses of the longer wavelengths of UVA. Although current published evidence suggests that the plasma levels of hypericin are unlikely to cause clinical phototoxicity, it has been established that photoactive compounds can cause DNA damage at sub-toxic and sub-erythemal doses, the effects of which might not be apparent for many years after the event. The present study used HaCaT keratinocytes to investigate the photoclastogenic ability of hypericin on irradiation with UVA. The results show that although the combination of hypericin and UVA light increased the genotoxic burden, when all factors are taken into account, the risk of significant photogenotoxic damage incurred by the combination of Hypericum extracts and UVA phototherapy may be low in the majority of individuals.     

Hypericum perforatum--chemical profiling and quantitative results of St. John's Wort products by an improved high-performance liquid chromatography method

The analysis of flavonoids, naphthodianthrones, and the phloroglucinol derivative hyperforin in H. perforatum is described in this article. In a 35-min HPLC run nine major compounds could be identified and baseline separated in the methanolic plant extracts. For an optimum separation the mobile phase consisted of 10 mM ammonium acetate buffer (pH 5.0) and an acetonitrile/methanol mixture; a Synergi MAX-RP 80 A column (C-12 material) was used as stationary phase. Detection was performed at 270 nm, and the identity of the compounds was confirmed in an LC-MS experiment. Commercial St. John's Wort products were analyzed and qualitative and quantitative results are discussed.     

In vitro and in vivo characterization of new formulations of St. John's Wort extract with improved pharmacokinetics and anti-nociceptive effect

The main purpose of the present study was to develop a novel formulation of St. John's Wort (SJW) extract with the aim of improving its pharmacokinetics and anti-nociceptive effect. Several formulations of SJW were prepared, including cyclodextrin inclusion (SJW-CD), solid dispersion (SJW-SD), dry-emulsion (SJW-DE), and nano-emulsion (SJW-NE). Physicochemical properties of SJW formulations were characterized with a focus on the morphology, dissolution behavior, colloidal properties, and dispersion stability in water. Although all the SJW formulations and SJW extract itself exhibited fine dissolution behavior in water, SJW extract and most formulations tended to cream, aggregate, or flocculate after dispersion in distilled water. In contrast, there were no significant changes in appearance and particle size of the SJW-NE for at least a few weeks, suggesting that SJW-NE was the most stable form as a carrier of SJW in the present study. After oral administration of the SJW-NE formulation (5.2 mg hyperforin/kg) in mice, higher hyperforin exposure in plasma (1188 ± 41 nM·h) and the brain (52.9 ± 1.6 pmol/g tissue·h) was observed with 2.8- and 1.3-fold increases of the area under the concentration curve from 0 to 6 hours (AUC(0-6)) compared to those of the SJW extract (417 ± 41 nM·h in plasma and 41.6 ± 1.5 pmol/g tissue·h in the brain). In the formalin test for scoring properties of the first and second phases of the pain response in mice, single oral administration of SJW-NE significantly reduced the nociceptive response compared with SJW extract. From these findings, the NE approach might be efficacious in improving the oral bioavailability and anti-nociceptive effect of SJW extract.     

Extracting Polar Biologically Active Substances from the Grass of St. John's Wort with a Two-Phase Extractant System in the Presence of Surfactants

Pharmaceutical Chemistry Journal -     

Evaluation of the association between St. John's wort and elevated thyroid-stimulating hormone.

STUDY OBJECTIVE: To evaluate whether St. John's wort is associated with an elevation in thyroid-stimulating hormone (TSH) levels. DESIGN: Retrospective case-control study SETTING: Hamilton, Ontario; September 1998-May 1999. SUBJECTS: Thirty-seven subjects with elevated TSH levels and 37 age- (+/- 6 yrs) and gender-matched subjects with normal TSH levels who resided in the same region. MEASUREMENTS AND MAIN RESULTS: Exposure to St. John's wort during the 3-6 months before TSH measurement was assessed through a telephone interview. A total of 4 of 37 subjects with elevated TSH levels and 2 of 37 subjects with normal TSH levels had taken St. John's wort in that time period. The odds ratio for elevated TSH levels associated with taking St. John's wort was 2.12 (95% confidence interval [CI] 0.36-12.36). CONCLUSION: This study suggests a probable association between St. John's wort and elevated TSH levels. However, because of the wide CIs surrounding the point estimate (which crosses unity), further investigation, including a large, prospective cohort study, is warranted.     

Comparison of equivalence between the St. John's wort extract LoHyp-57 and fluoxetine.

In a randomised double-blind comparative trial, the antidepressant efficacy of a daily dose of 800 mg of the St. John's wort extract LoHyp-57 (dry extract of St. John's wort, drug extrakt ratio 5-7:1, solvent, ethanol 60% [w/w]) was shown to be equivalent to that of 20 mg fluoxetine (CAS 54910-89-3) in elderly patients with mild or moderate depressive episodes according to ICD 10 (International Statistical Classification of Diseases and Related Health Problems). Treatment was given for six weeks. 149 out-patients (129 females and 20 males) were included in the intention-to-treat analysis. 72 of these patients were assigned to the ICD 10 diagnostic criterion F32.0 (mild depressive episode), while 77 patients were suffering from moderate depressive episodes, corresponding to F32.1. The principal target criterion was the patient's global score on the HAMILTON Depression Scale (items 1-17). During the six-week course of treatment with LoHyp-57, the HAMILTON global score fell from 16.60 points at entry to 7.91 points, and in the fluoxetine sample it fell from 17.18 to 8.11 points. In the group of patients with mild depressive episodes, the score showed a mean fall from 14.21 to 6.21 points on LoHyp-57, and from 15.21 to 7.46 points on fluoxetine. In patients with moderate depressive episodes, the score showed a mean fall from 18.73 to 9.43 points on LoHyp-57 and from 19.10 to 8.75 points on fluoxetine. The efficacy of both medications was found to be equivalent both in mild and moderate depressive episodes. Both treatment groups showed adverse drug reactions (ADRs). Twelve ADRs with a possible relationship to the study medication were reported during treatment with LoHyp-57. Six patients were prematurely withdrawn from treatment with the study medication for this reason. On fluoxetine 17 ADRs occurred with a possible relationship to the study medication. These led to abandonment of treatment and therefore premature withdrawal from the study in 8 cases.     

Effects of insulin and St. John's Wort treatments on anxiety, locomotory activity, depression, and active learning parameters of streptozotocin-diabetic rats

The aim of this work was to investigate the effects of St.?John's Wort (SJW) extract treatment on behavioral changes arising in streptozotocin (STZ)-diabetic rats. Plus-maze, activity cage, modified forced swimming, and active avoidance tests were performed for evaluating exploratory behaviors, spontaneous locomotor activities, depression levels, and learning parameters of animals, respectively. Obtained data exhibited a diabetes mellitus (DM)-induced increase in anxiety and depression levels, decrease in spontaneous locomotor activities, and impairment of learning parameters in rats even in the early stages of the disease. Daily insulin replacement (2?IU/kg/day) could not restore these impaired parameters completely, indicating the need of novel therapeutic approaches. SJW extract (125 and 250?mg/kg) treatments for seven days provided significant improvement in all of the impaired parameters observed in this study, probably due to its antidiabetic and central nervous system (CNS)-related effects. Based on the findings of the present study, it may be suggested that SJW extracts may be of help to diabetic patients suffering from depressive moods, sleeping disturbances, and cognitive deficits and may provide a new potential alternative for the treatment of psychiatric complications of diabetes.     

St. John's Wort (Hypericum perforatum) induces overexpression of multidrug resistance protein 2 (MRP2) in rats: a 30-day ingestion study.

St. John's Wort (Hypericum perforatum, SJW) has been used as a herbal medicine for the treatment of depression in oral doses of 900-1050 mg/day in humans. However, the ingestion of SJW was reported to cause interactions with drugs. In the present study, we examined the effects of SJW treatment on the induction of drug transporters and enzymes in rats. An immunoblot analysis was performed to quantify the expression of the transporters and enzymes. SJW was given at a dose of 400 mg/kg/day, since it was reported that 400 mg/kg/day is antidepressant effective dose in rats. When SJW was administered for 10 days, the amounts of multidrug resistance protein 2 (MRP2), glutathione S-transferase-P (GST-P) and cytochrome P450 1A2 (CYP1A2) in the liver were increased to 304%, 252% and 357% of controls, respectively, although the amounts of P-glycoprotein and multidrug resistance protein 1 were not changed. Under the same conditions, an increase of MRP2 in the kidney was not observed. The increase in the levels of each protein was maximal at 10 days after SJW treatment and lasted for at least 30 consecutive days. These results suggest that SJW induces hepatic MRP2, GST-P and CYP1A2 overexpressions, and thus, it could affect drug metabolism, conjugation and disposition.