St John's Wort: A Hidden Risk for Transplant Patients

Evidence of the interactions between immunosuppressive drugs used in autoimmune rheumatic diseases and Chinese herbal medicine: A scoping review

OBJECTIVES

Chinese herbal medicine (CHM) has been shown to be effective in autoimmune rheumatic diseases, but harmful herb-drug interactions might be inherent. We aim to review the evidence regarding herb-drug interactions between immunosuppressive drugs used in autoimmune rheumatic diseases and CHM.

METHODS

We searched PubMed, EMBASE and CINAHL from inception till 30 April 2023 using keywords that encompassed 'herb-drug interactions', 'herbs' and 'immunosuppressants'. Articles were included if they contained reports about interactions between immunosuppressive drugs used in the treatment of rheumatic diseases with CHM. Level of evidence for each pair of interaction was graded using the algorithm developed by Colalto.

RESULTS

A total of 65 articles and 44 unique pairs of interactions were identified. HDIs were reported for cyclophosphamide, cyclosporine, tacrolimus, methotrexate, mycophenolic acid, glucocorticoids, sulfasalazine, tofacitinib and biologic disease-modifying antirheumatic drugs. Among these, cyclosporine (n = 27, 41.5%) and tacrolimus (n = 19, 29.2%) had the highest number of documented interactions. Hypericum perforatum had the highest level of evidence of interaction with cyclosporine and tacrolimus. Consumption reduced the bioavailability and therapeutic effects of the drugs. Schisandra sphenanthera had the highest level of evidence of interaction with tacrolimus and increased the bioavailability of the drug. Majority of the articles were animal studies.

CONCLUSION

Overall level of evidence for the included studies were low, though interactions between cyclosporine, tacrolimus, Hypericum perforatum and Schisandra sphenanthera were the most and well-documented. Healthcare professionals should actively enquire about the concurrent use of CHM in patients, especially when drugs with a narrow therapeutic index are consumed.

Safety and Molecular-Toxicological Implications of Cannabidiol-Rich Cannabis Extract and Methylsulfonylmethane Co-Administration

Cannabidiol (CBD) is a biologically active, non-psychotropic component of Cannabis sativa whose popularity has grown exponentially in recent years. Besides a wealth of potential health benefits, ingestion of CBD poses risks for a number of side effects, of which hepatotoxicity and CBD/herb-drug interactions are of particular concern. Here, we investigated the interaction potential between the cannabidiol-rich cannabis extract (CRCE) and methylsulfonylmethane (MSM), a popular dietary supplement, in the mouse model. For this purpose, 8-week-old male C57BL6/J mice received MSM-containing water (80 mg/100 mL) ad libitum for 17 days. During the last three days of treatment, mice received three doses of CRCE administered in sesame oil via oral gavage (123 mg/kg/day). Administration of MSM alone did not result in any evidence of liver toxicity and did not induce expression of mouse cytochrome P450 (CYP) enzymes. Administration of CRCE did produce significant (p < 0.05) increases in Cyp1a2, Cyp2b10, Cyp2c29, Cyp3a4, Cyp3a11, Cyp2c65, and Cyp2c66 messenger RNA, however, this effect was not amplified by MSM/CRCE co-treatment. Similarly, no evidence of liver toxicity was observed in MSM/CRCE dosed mice. In conclusion, short-term MSM/CRCE co-administration did not demonstrate any evidence of hepatotoxicity in the mouse model.

What has been the impact of the Traditional Herbal Registration (THR) scheme in the UK on information provided with herbal products bought over the counter?

BACKGROUND

In 2011 there was a strengthening of European Union (EU) legislation on the licencing of herbal products which, in the UK, resulted in the introduction of the Traditional Herbal Registration (THR) scheme. This scheme sets out standards for the safety and quality of herbal medicines and includes the provision of information to the customer on the safe use of the product. The aim of this study is to replicate a survey undertaken in 2011, prior to the implementation of the THR scheme, and evaluate the impact of this scheme on the information provided with herbal products bought over-the-counter.

METHODS

We undertook a survey on 5 herbal products commonly available over-the-counter (St John's wort, echinacea, Ginkgo biloba, Asian ginseng, garlic). The information was searched for key safety messages identified by the National Center for Complementary and Integrative Health (NCCIH). We also explored the presence of risk of harm information.

RESULTS

We recorded a rise in the number of products registered with the THR scheme (37% in 2016 compared to 7% in 2011). We also identified a reduction in the number of products that did not contain key safety information (75% in 2011 compared to 20% of products obtained in 2016). Risk of harm information was only communicated in products containing a PIL. We identified more products containing frequency of risk of harm information but this was not statistically significant.

CONCLUSION

The introduction of the THR scheme appears to be associated with an increase in the provision of information about key safety messages on the safe use of herbal products. However, it is important to note that at least half of the products on the market that are not included in the THR scheme do not contain any information about their safe use; this includes information about precautions, interactions and side effects. The use of NCCIH herbal monographs replicated the methods used in the previous study; we recognise that the use of a different resource might effect the appraisal of the information provided. We also acknowledge that surveying presence of information does not assure that the latter is effectively communicated to patients, for which a close textual analysis would be required. While it is promising that more information is available after the introduction of the THR scheme, the public needs to be informed about ways to optimise safe use of all herbal products.

Kidney toxicity related to herbs and dietary supplements: Online table of case reports. Part 3 of 5 series

BACKGROUND

No tabular summary of potentially life-threatening, kidney-toxic dietary supplements (DS; includes herbs) based on PubMed case reports is currently available online and continually updated to forewarn United States consumers, clinicians, and companies manufacturing DS. The purpose of this review was to create an online research summary table of kidney toxicity case reports related to DS.

METHODS

Documented PubMed case reports (1966 to May 2016, and cross-referencing) of DS appearing to contribute to kidney toxicity were listed in "DS Toxic Tables." Keywords included "herb" or "dietary supplement" combined with "kidney" to generate an overview list, and possibly "toxicity" to narrow the selection. Case reports were excluded if they involved herb combinations (some exceptions), Chinese herb mixtures, teas of mixed herb contents, mushrooms, poisonous plants, self-harm, excessive doses (except vitamins/minerals), legal or illegal drugs, drug-herbal interactions, and confounders of drugs or diseases. Since commercial DS often include a combination of ingredients, they were treated separately; so were foods. A few foods with kidney-toxic effects were listed in a fourth table. The spectrum of herbal or DS-induced kidney injuries included kidney stones, nephritis, nephrotic syndrome, necrosis, acute kidney injury (AKI; previously known as acute renal failure [ARF]), chronic kidney disease, kidney transplant, and death.

RESULTS

Approximately 7 herbs (minus 4 no longer for sale) and 10 dietary supplements (minus 3 excluded due to excessive doses + germanium that is no longer sold) have been related to kidney injury case reports published in PubMed (+crosslisting) in the last 50 + years (1966 to May 2016). The implicated herbs include Chinese yew (Taxus celbica) extract, impila (Callilepis laureola), morning cypress (Cupressus funebris Endl), St. John's wort (Hypericum perforatum), thundergod vine (Tripterygium wilfordii hook F), tribulus (Tribulus terrestris) and wormwood (Artemisia herba-alba). No longer sold in the United States are chocolate vine or mu tong (Caulis aristolochiae), guang fang ji (Aristolochia fangchi), ma huang (Ephedra sinica), and Tenshin Tokishigyaku-ka-goshuyu-shokyo-to. The DS include bile (sheep), chlorella, chromium (Cr), CKLS, creatine, gallbladder (fish), glucosamine, hydrazine, N.O.-Xplode, Spanish fly, and excess intakes of vitamins A, C, and D. Germanium (Ge) is not available for sale. The top two DS with the largest number of reported publications, but not always case reports, in descending order, were the aristolochic acid-containing herbs guang fang ji (mistaken identity) and chocolate vine or mu tong. The remaining DS featured one to three publications over a 50+ year period. Numerous case reports were reported for kidney-toxic foods: djenkol bean, gallbladders (carp fish, pufferfish, & snake), and star fruit (only in chronic kidney disease patients), and uncooked yam powder or juice.

CONCLUSION

This online "DS Toxic Table" provides clinicians, consumers, and manufacturers with a list of herbs that could potentially contribute to kidney injuries.

Natural Health Product Interactions with Medication

Natural health products (or dietary supplements) refer to those products found in oral dosage forms, containing 1 or more active ingredients considered to be a nutrient, an herbal product, or any other nonnutrient/nonherbal substance. Their use continues to increase in the general population and in patients seen by nutrition support clinicians. Aside from an appraisal of product safety and effectiveness, attention should be paid to the potential for these product ingredients to interact with medication. Estimates are that at least 15 million adults in the United States are at risk for supplement-drug interactions. These can occur through both pharmacokinetic and pharmacodynamic mechanisms. This review describes the influence of dietary supplements on both the disposition and the effect of medication and provides numerous examples. Patients at greatest risk for interactions are those with chronic disease, who use multiple medications-particularly those with a narrow therapeutic range-have genetic variants in drug metabolism, impaired organ function, and are at either end of the age spectrum. Knowledge of the specific effects on drug absorption, metabolism, and effect is still incomplete. Relative to the large number of possible interactions between supplements and medication, only a small number of combinations have been examined or reported. The greatest limiting factor remains the quality or reliability of the existing evidence, as many widely accepted interactions are only theoretical based either on in vitro data or known pharmacology. A distinction needs to be clearly drawn between "documented" interactions and "potential" interactions. Although drug-drug interactions have been widely recognized, supplement-drug interactions may be as important to recognize, report, and manage.

Drug-botanical interactions: a review of the laboratory, animal, and human data for 8 common botanicals

Many Americans use complementary and alternative medicine (CAM) to prevent or alleviate common illnesses, and these medicines are commonly used by individuals with cancer.These medicines or botanicals share the same metabolic and transport proteins, including cytochrome P450 enzymes (CYP), glucuronosyltransferases (UGTs), and P-glycoprotein (Pgp), with over-the-counter and prescription medicines increasing the likelihood of drug-botanical interactions.This review provides a brief description of the different proteins, such as CYPs, UGTs, and Pgp.The potential effects of drug-botanical interactions on the pharmacokinetics and pharmacodynamics of the drug or botanical and a summary of the more common models used to study drug metabolism are described.The remaining portion of this review summarizes the data extracted from several laboratory, animal, and clinical studies that describe the metabolism, transport, and potential interactions of 8 selected botanicals. The 8 botanicals include black cohosh, Echinacea, garlic, Gingko biloba, green tea, kava, milk thistle, and St John's wort; these botanicals are among some of the more common botanicals taken by individuals with cancer.These examples are included to demonstrate how to interpret the different studies and how to use these data to predict the likelihood of a clinically significant drug-botanical interaction.

Herb-drug interactions with St John's wort (Hypericum perforatum): an update on clinical observations

St John's wort (SJW) extracts, prepared from the aerial parts of Hypericum perforatum, contain numerous pharmacologically active ingredients, including naphthodianthrones (e.g., hypericin and its derivatives), phloroglucinols derivatives (e.g., hyperforin, which inhibits the reuptake of a number of neurotransmitters, including serotonin), and flavonoids. Such extracts are widely used for the treatment of mild-to-moderate depression. As a monotherapy, SJW has an encouraging safety profile. However, relevant and, in some case, life-threatening interactions have been reported, particularly with drugs which are substrate of cytochrome P450 and/or P-glycoprotein. Well-documented SJW interactions include (1) reduced blood cyclosporin concentration, as suggested by multiple case reports as well as by clinical trials, (2) serotonin syndrome or lethargy when SJW was given with serotonin reuptake inhibitors, (3) unwanted pregnancies in women while using oral contraceptives and SJW, and (4) reduced plasma drug concentration of antiretroviral (e.g., indinavir, nevirapine) and anticancer (i.e., irinotecan, imatinib) drugs. Hyperforin, which is believed to contribute to the antidepressant action of St John's wort, is also strongly suspected to be responsible of most of the described interactions.

Nuclear receptors CAR and PXR: Molecular, functional, and biomedical aspects

Nuclear receptors (NRs) are ligand-activated transcription factors sharing a common evolutionary history and having similar sequence features at the protein level. Selective ligand(s) for some NRs is not known, therefore these NRs have been named "orphan receptors". Whenever ligands have been recognized for any of the orphan receptor, it has been categorized and grouped as "adopted" orphan receptor. This group includes the constitutive androstane receptor (CAR) and the pregnane X receptor (PXR). They function as sensors of toxic byproducts derived from endogenous metabolites and of exogenous chemicals, in order to enhance their elimination. This unique function of CAR and PXR sets them apart from the steroid hormone receptors. The broad response profile has established that CAR and PXR are xenobiotic sensors that coordinately regulate xenobiotic clearance in the liver and intestine via induction of genes involved in drug and xenobiotic metabolism. In the past few years, research has revealed new and mostly unsuspected roles for CAR and PXR in modulating hormone, lipid, and energy homeostasis as well as cancer and liver steatosis. The purpose of this review is to highlight the structural and molecular bases of CAR and PXR impact on human health, providing information on mechanisms through which diet, chemical exposure, and environment ultimately impact health and disease.

Nursing and Transplant Coordination: A Call for Clarity

Organ transplantation is a complex and highly regulated field. This review focuses on the role of nurses and transplant coordinators in solid organ transplantation, excluding both inpatient staff nursing and procurement activities. The literature describes a robust and autonomous transplant coordinator role; a key member of the multidisciplinary transplant team. Transplant coordinators facilitate patient care throughout all phases of transplantation. However, a lack of consensus on licensure and educational preparation of these important practitioners was evident from the review of literature. Synthesis of the data suggests that the role of transplant coordinator is not distinct but a description of a wide variety of functions, duties, and tasks that require varying levels of licensure and educational preparation. Greater clarity for both practitioners and consumers could be achieved by creating certification levels similar to nephrology nurses. As no transplant-specific staffing models or benchmarks were discovered, rigorous research regarding optimal staffing patterns is also recommended.

The effect of food components on the absorption of P-gp substrates: a review

P-glycoprotein (P-gp), a well characterized efflux mechanism which is functionally expressed in the intestinal epithelium, constitutes, along with intestinal metabolism, an important part of the biochemical barrier function of the intestinal mucosa. This efflux carrier may be responsible for limiting the bioavailability of several drugs after oral intake. Recently, increasing attention is being paid to the interaction of dietary components with the intestinal absorption of drugs. This review focuses on the modulating capacity of food components on the intestinal absorption of P-gp substrates. The possible P-gp inhibitory effects of several dietary constituents are discussed. In addition, this review will also focus on the effect of several bioflavonoids on the P-gp-mediated efflux of drugs. As the role of P-gp (and other efflux carriers, including multidrug resistance-associated proteins and breast cancer resistance protein) in limiting the bioavailability of drugs becomes more clear, more research is required firstly to identify the effect of dietary compounds on these efflux carriers and secondly to reveal the clinical relevance of this interaction.

Alterations in cyclosporin A pharmacokinetics and metabolism during treatment with St John's wort in renal transplant patients

AIM

This study investigated the effects of St John's wort extract (SJW) on the pharmacokinetics and metabolism of the immunosuppressant cyclosporin A (CSA).

METHODS

In an open-label study, 11 renal transplant patients received 600 mg SJW extract daily for 14 days in addition to their regular regimen of CSA. Blood concentrations of CSA and its metabolites AM1, AM1C, AM9, AM19, and AM4N were measured by HPLC.

RESULTS

After 2 weeks of SJW coadministration, dose-corrected AUC0-12, Cmax and Ctrough values for CSA decreased significantly by 46%[geometric mean ratio baseline/SJW (95% CI): 1.83 (1.63-2.05)], 42%[1.72 (1.42-2.08)], and 41%[1.70 (1.17-2.47)], respectively. CSA doses were increased from a median of 2.7 mg day(-1) kg(-1) at baseline to 4.2 mg day(-1) kg(-1) at day 15, with the first dose adjustment required only 3 days after initiation of SJW treatment. Additionally, the metabolite pattern of CSA was substantially altered during SJW treatment. Whereas dose-corrected AUC values for AM1, AM1c and AM4N significantly decreased by 59%, 61%, and 23% compared with baseline, AUC values for AM9 and AM19 were unchanged. Following the increase in CSA dose, observed AUC and Cmax values for AM9, AM19, and AM4N increased by 20-51% and 43-90%, respectively.

CONCLUSION

Administration of SJW extract to patients receiving CSA treatment resulted in a rapid and significant reduction of plasma CSA concentrations. Additionally, the substantial alterations in CSA metabolite kinetics observed may affect the toxicity profile of the drug.