Drug interactions in African herbal remedies

Pharmacokinetic and pharmacodynamic herb-drug interactions-part I. Herbal medicines of the central nervous system

Unlike conventional drug substances, herbal medicines are composed of a complex of biologically active compounds. Therefore, the potential occurrence of herb-drug interactions is even more probable than for drug-drug interactions. Interactions can occur on both the pharmacokinetic and pharmacodynamic level. Herbal medicines may affect the resulting efficacy of the concomitantly used (synthetic) drugs, mainly on the pharmacokinetic level, by changing their absorption, distribution, metabolism, and excretion. Studies on the pharmacodynamic interactions of herbal medicines and conventional drugs are still very limited. This interaction level is related to the mechanism of action of different plant constituents. Herb-drug interactions can cause changes in drug levels and activities and lead to therapeutic failure and/or side effects (sometimes toxicities, even fatal). This review aims to provide a summary of recent information on the potential drug interactions involving commonly used herbal medicines that affect the central nervous system (Camellia, Valeriana, Ginkgo, Hypericum, Humulus, Cannabis) and conventional drugs. The survey databases were used to identify primary scientific publications, case reports, and secondary databases on interactions were used later on as well. Search keywords were based on plant names (botanical genera), officinal herbal drugs, herbal drug preparations, herbal drug extracts.

Determinants of COVID-19-related knowledge and disrupted habits during epidemic waves among women of childbearing age in urban and rural areas of the Malagasy Middle East

BACKGROUND

With regard to the coronavirus disease (COVID-19) pandemic in Madagascar, little is known about the knowledge, the perceptions and the impacts of this disease on women of childbearing age. People's knowledge of COVID-19 can have an impact on their attitudes towards seeking care. The aim of the current study is to determine the knowledge of COVID-19 and associated determinants among women of childbearing age in Moramanga.

METHODS

A cross-sectional study based on questionnaire administration was used among women of childbearing age. Data collection was conducted from August to October 2021. A scoring method was applied to evaluate their knowledge level and perceptions about COVID-19 and its impacts on their lives. A binary stepwise logistic regression was performed to determine the sociodemographic determinants of their knowledge level about COVID-19.

RESULTS

A total of 885 women of childbearing age from urban and rural Moramanga areas were interviewed. Approximately 49.8% (441/885) lived in urban areas, and 50.2% (444/885) lived in rural areas. Approximately 35.3% (322/885) of the participants had a good level of knowledge of COVID-19. Multivariate analysis showed that the probability of having a good level of knowledge of COVID-19 had a significant statistical association (p value < 0.05) with living in an urban area [AOR: 2.89; 95% CI (1.89-4.42)], telephone ownership [AOR: 1.71; 95% CI (1.16-2.53)], radio ownership [AOR 2.2; 95% CI (1.43-3.38)], watching TV [AOR = 1.95; 95% CI (1.34-2.83)] and reading journal papers [AOR = 3.74 95% CI (1.69-8.27)].

CONCLUSIONS

Almost a third of the sampled women of childbearing age had a good level of knowledge of COVID-19. Access to information through telecommunications technologies increases the chances of being better informed about the disease. To avoid the negative repercussions of infectious disease epidemics, it is necessary to improve the awareness of childbearing women about these diseases by taking demographic features of the population into account.

Prevalence, Perception and Predictors of Concomitant Herbal Medicine Use among HIV/AIDS and Tuberculosis Patients in Metekel Zone, Northwest Ethiopia: A Cross-Sectional Study

BACKGROUND

The use of herbal medicine is common in Ethiopia. However, evidence on the extent and predictors of concomitant use of herbal medicine with conventional treatment among HIV/AIDS and tuberculosis patients is limited.

OBJECTIVE

To assess the extent of concomitant use of herbal medicine with conventional therapy and associated factors among HIV/AIDS and tuberculosis patients in Metekel Zone, Northwest Ethiopia.

METHOD

A cross-sectional study was conducted from January to March 2020. HIV/AIDS and tuberculosis patients who visited the health facilities during the study were interviewed face-to-face using a structured and pretested questionnaire. The descriptive statistics and univariate and multivariate logistic regression analyses were conducted using SPSS version 25. A P-value of <0.05 was considered significant.

RESULTS

412 patients on conventional treatment were included in this study; 355 (86.2%) were HIV patients, and 57 (13.8%) were TB patients. More than half, 217 (52.7%) participants reported using herbal medicine while on conventional therapy. Among those who claimed to have used herbal medicines, 32 (14.7%) received herbal medicine from traditional healers. About four of five herbal users did not disclose their use to their healthcare providers. The type of health facility on follow-up (P=0.03), disease status (P=0.01), occupation (P=0.02), discontinuing ART (P=0.03), and encountering side (P=0.04) were the determinant factors for the use of herbal medicine among our study participants.

CONCLUSION

In the Metekel Zone, concomitant consumption of herbal medication is common among HIV/AIDS and tuberculosis patients. Furthermore, most patients did not disclose the healthcare practitioners about their herbal use. Therefore, healthcare practitioners must assess and counsel patients regarding the potential adverse effects and herb-drug interaction to optimize therapy.

From Bush Medicine to Modern Phytopharmaceutical: A Bibliographic Review of Devil's Claw (Harpagophytum spp.)

Devil's claw (Harpagophytum spp., Pedaliaceae) is one of the best-documented phytomedicines. Its mode of action is largely elucidated, and its efficacy and excellent safety profile have been demonstrated in a long list of clinical investigations. The author conducted a bibliographic review which not only included peer-reviewed papers published in scientific journals but also a vast amount of grey literature, such as theses and reports initiated by governmental as well as non-governmental organizations, thus allowing for a more holistic presentation of the available evidence. Close to 700 sources published over the course of two centuries were identified, confirmed, and cataloged. The purpose of the review is three-fold: to trace the historical milestones in devil's claw becoming a modern herbal medicine, to point out gaps in the seemingly all-encompassing body of research, and to provide the reader with a reliable and comprehensive bibliography. The review covers aspects of ethnobotany, taxonomy, history of product development and commercialization, chemistry, pharmacology, toxicology, as well as clinical efficacy and safety. It is concluded that three areas stand out in need of further investigation. The taxonomical assessment of the genus is outdated and lacking. A revision is needed to account for intra- and inter-specific, geographical, and chemo-taxonomical variation, including variation in composition. Further research is needed to conclusively elucidate the active compound(s). Confounded by early substitution, intermixture, and blending, it has yet to be demonstrated beyond a reasonable doubt that both (or all) Harpagophytum spp. are equally (and interchangeably) safe and efficacious in clinical practice.

Self-Medication and Safety Profile of Medicines Used among Pregnant Women in a Tertiary Teaching Hospital in Jimma, Ethiopia: A Cross-Sectional Study

Background: Despite the potential foetal and maternal risks of self-medication, studies on self-medication and safety profile of medicines used during pregnancy are scarce. This study determined the prevalence, predictors and safety profile of medicines used for self-medication during pregnancy at Jimma University Medical Centre (JUMC) in Ethiopia. Methods: A hospital-based cross sectional study was conducted on 1117 hospitalized pregnant women or postpartum women in the maternity and gynaecology wards at JUMC between February and June 2017. Data were collected using an interviewer-administered structured questionnaire and by reviewing patient medical records. Data were analysed using descriptive statistics and logistic regression. Result: Nearly 3 out of 10 women reported taking at least one type of conventional medicine for self-medication, mainly analgesics 92.3%. Almost 75.0% of the self-medicated women used medicines classified as probably safe and 13.6% as potentially risky to use during pregnancy. Medicinal plant use, religion and access to a health facility near their residency were significantly associated with self-medication during pregnancy. Conclusions: Self-medication is common among pregnant women at JUMC. Most women used medicines classified as safe to use during pregnancy. There is need for enlightenment of pregnant women on the potential dangers of self-medication during pregnancy to prevent foetal and maternal risks.

Building Capability for Clinical Pharmacology Research in Sub-Saharan Africa

A strong scientific rationale exists for conducting clinical pharmacology studies in target populations because local factors such as genetics, environment, comorbidities, and diet can affect variability in drug responses. However, clinical pharmacology studies are not widely conducted in sub-Saharan Africa, in part due to limitations in technical expertise and infrastructure. Since 2012, a novel public-private partnership model involving research institutions and a pharmaceutical company has been applied to developing increased capability for clinical pharmacology research in multiple African countries.

Adapting an adherence support workers intervention: engaging traditional healers as adherence partners for persons enrolled in HIV care and treatment in rural Mozambique

BACKGROUND

Systematic adaptation of evidence-informed interventions that increase retention in care and improve adherence to antiretroviral therapy (ART) are essential to ending the HIV epidemic in rural sub-Saharan Africa. We selected and adapted an adherence support worker intervention employed in Malawi for use by traditional healers in rural Mozambique. Given the levels of trust and dependence previously expressed by persons living with HIV (PLHIV) for traditional medicine, we adapted the program to engage traditional healers within the allopathic health system.

METHODS

Adaption followed a theoretically driven approach to intervention adaption: the Assessment-Decision-Administration-Production-Topical Experts-Integration-Training-Testing (ADAPT-ITT) model. Three rounds of performance feedback, based on theater presentations of the adapted intervention for stakeholders and idea generation, were completed with 12 groups from March to July 2016 to develop the final model. We offered healer support to 180 newly diagnosed HIV-infected patients.

RESULTS

Traditional healers were an acceptable group of community health workers to assist with patient adherence and retention. Traditional healers, clinicians, and interested community members suggested novel strategies to tailor the adherence support worker intervention, revealing a local culture of HIV denialism, aversion to the health system, and dislike of healthcare providers, as well as a preference for traditional treatments. Proposed changes to the intervention included modifications to the training language and topics, expanded community-based activities to support acceptability of an HIV diagnosis and to facilitate partner disclosure, and accompaniment to the health facility by healers to encourage delivery of respectful clinical care. PLHIV, healers, and clinicians deemed the intervention socially acceptable during focus groups. We subsequently recruited 180 newly diagnosed HIV-infected patients into the program: 170 (94%) accepted.

CONCLUSIONS

Systematic translation of interventions, even between regions with similar social and economic environments, is an important first step to successful program implementation. Efforts previously limited to community health workers can be tailored for use by traditional healers-an underutilized and often maligned health workforce. It proved feasible to use theater-based performances to demonstrate delivery of the intervention in low-literacy populations, generating discussions about social norms, community concerns, and the merits of an acceptable strategy to improve retention and adherence to ART.

Adapting an adherence support workers intervention: engaging traditional healers as adherence partners for persons enrolled in HIV care and treatment in rural Mozambique

BACKGROUND

Systematic adaptation of evidence-informed interventions that increase retention in care and improve adherence to antiretroviral therapy (ART) are essential to ending the HIV epidemic in rural sub-Saharan Africa. We selected and adapted an adherence support worker intervention employed in Malawi for use by traditional healers in rural Mozambique. Given the levels of trust and dependence previously expressed by persons living with HIV (PLHIV) for traditional medicine, we adapted the program to engage traditional healers within the allopathic health system.

METHODS

Adaption followed a theoretically driven approach to intervention adaption: the Assessment-Decision-Administration-Production-Topical Experts-Integration-Training-Testing (ADAPT-ITT) model. Three rounds of performance feedback, based on theater presentations of the adapted intervention for stakeholders and idea generation, were completed with 12 groups from March to July 2016 to develop the final model. We offered healer support to 180 newly diagnosed HIV-infected patients.

RESULTS

Traditional healers were an acceptable group of community health workers to assist with patient adherence and retention. Traditional healers, clinicians, and interested community members suggested novel strategies to tailor the adherence support worker intervention, revealing a local culture of HIV denialism, aversion to the health system, and dislike of healthcare providers, as well as a preference for traditional treatments. Proposed changes to the intervention included modifications to the training language and topics, expanded community-based activities to support acceptability of an HIV diagnosis and to facilitate partner disclosure, and accompaniment to the health facility by healers to encourage delivery of respectful clinical care. PLHIV, healers, and clinicians deemed the intervention socially acceptable during focus groups. We subsequently recruited 180 newly diagnosed HIV-infected patients into the program: 170 (94%) accepted.

CONCLUSIONS

Systematic translation of interventions, even between regions with similar social and economic environments, is an important first step to successful program implementation. Efforts previously limited to community health workers can be tailored for use by traditional healers-an underutilized and often maligned health workforce. It proved feasible to use theater-based performances to demonstrate delivery of the intervention in low-literacy populations, generating discussions about social norms, community concerns, and the merits of an acceptable strategy to improve retention and adherence to ART.

Cytochrome P450 and P-Glycoprotein-Mediated Interactions Involving African Herbs Indicated for Common Noncommunicable Diseases

Herbal remedies are regularly used to complement conventional therapies in the treatment of various illnesses in Africa. This may be because they are relatively cheap and easily accessible and are believed by many to be safe, cause fewer side effects, and are less likely to cause dependency. On the contrary, many herbs have been shown to alter the pharmacokinetics of coadministered allopathic medicines and can either synergize or antagonize therapeutic effects as well as altering the toxicity profiles of these drugs. Current disease burden data point towards epidemiological transitions characterised by increasing urbanization and changing lifestyles, risk factors for chronic diseases like hypertension, diabetes, and cancer which often present as multimorbidities. As a result, we highlight African herb-drug interactions (HDIs) modulated via cytochrome P450 enzyme family (CYP) and P-glycoprotein (P-gp) and the consequences thereof in relation to antihypertensive, antidiabetic, and anticancer drugs. CYPs are enzymes which account for to up to 70% of drug metabolism while P-gp is an efflux pump that extrudes drug substrates out of cells. Consequently, regulation of the relative activity of both CYP and P-gp by African herbs influences the effective drug concentration at the site of action and modifies therapeutic outcomes.

Engagement of Traditional Healers and Birth Attendants as a Controversial Proposal to Extend the HIV Health Workforce

"Medical pluralism" is the use of multiple health systems and is common among people living with HIV/AIDS in sub-Saharan Africa. Healers and traditional birth attendants (TBAs) often are a patient's first and/or preferred line of treatment; this often results in delayed, interrupted, or abandoned diagnosis and therapy. Literature from the study of medical pluralism suggests that HIV care and treatment programs are infrequently and inconsistently engaging healers around the world. Mistrust and misunderstanding among patients, clinical providers, and traditional practitioners make the development of effective partnerships difficult, particularly regarding early HIV diagnosis and antiretroviral therapy. We provide recommendations for the development of successful collaboration health workforce efforts based on both published articles and case studies from our work in rural Mozambique.

Symptomatic HIV-positive persons in rural Mozambique who first consult a traditional healer have delays in HIV testing: a cross-sectional study

OBJECTIVE

Delays in HIV diagnosis and initiation of antiretroviral therapy are common even among symptomatic individuals in Africa. We hypothesized that antiretroviral therapy delays might be more common if traditional healers (THs) were the first practitioners consulted.

DESIGN

Cross-sectional study.

METHODS

We interviewed 530 newly diagnosed HIV-infected adults (≥18 years of age) who were clinically symptomatic at the time of HIV testing in 2 rural districts in Zambézia Province, Mozambique. We ascertained their previous health care seeking behavior, duration of their symptoms, CD4 cell counts at the time of entry into care, and treatment provided by TH(s).

RESULTS

Of 517 patients (97.5%) with complete histories, 62% sought care from a healer before presenting to the local health facility. The median time to first health facility visit from first relevant symptom was 2 months [interquartile range (IQR): 1-4.5] for persons who had not visited a healer, 3 months (IQR: 2-6) for persons visiting 1 healer, and 9 months (IQR: 5-12) for persons visiting >1 healer (P < 0.001). Healers diagnosed 56% of patients with a social or ancestral curse and treated 66% with subcutaneous herbal remedies. A nonsignificant trend toward lower CD4 cells for persons who had seen multiple healers was noted.

CONCLUSIONS

Seeking initial care from healers was associated with delays in HIV testing among symptomatic HIV-seropositive persons. We had no CD4 evidence that sicker patients bypass THs, a potential inferential bias. Engaging THs in a therapeutic alliance may facilitate the earlier diagnosis of HIV/AIDS.

Impact of traditional African medicine on drug metabolism and transport

INTRODUCTION

Africa is a continent of rich plant biodiversity with many indigenous plants having a long history of being used for medicinal purposes. A considerable number of patients consult traditional healers in African countries for their primary health-care needs. As Western medicines become more available through governmental programmes to treat diseases such as infections with HIV/AIDS, patients are faced with an increased potential of herb-drug interactions.

AREAS COVERED

Several medicinal herbs indigenous to Africa are discussed in terms of their effects on pharmacokinetics of allopathic drugs through modulation of enzymes and active transporters. Clinically relevant herb-drug interactions obtained from in vivo studies are discussed, with data from in vitro studies also included to ensure a complete review.

EXPERT OPINION

Traditional herbal medicines are often used under a false sense of security because of the perception that it is safe due to its natural origin. The potential for interactions between herbal and allopathic drugs is often neglected. Data on clinically relevant herb-drug interactions from clinical trials can be used to educate health-care workers and patients, contributing to improved therapeutic outcomes.

Models of drug-induced liver injury for evaluation of phytotherapeutics and other natural products

Extracts from medicinal plants, many of which have been used for centuries, are increasingly tested in models of hepatotoxicity. One of the most popular models to evaluate the hepatoprotective potential of natural products is acetaminophen (APAP)-induced liver injury, although other hepatotoxicity models such as carbon tetrachloride, thioacetamide, ethanol and endotoxin are occasionally used. APAP overdose is a clinically relevant model of drug-induced liver injury. Critical mechanisms and signaling pathways, which trigger necrotic cell death and sterile inflammation, are discussed. Although there is increasing understanding of the pathophysiology of APAP-induced liver injury, the mechanism is complex and prone to misinterpretation, especially when unknown chemicals such as plant extracts are tested. This review discusses the fundamental aspects that need to be considered when using this model, such as selection of the animal species or in vitro system, timing and dose-responses of signaling events, metabolic activation and protein adduct formation, the role of lipid peroxidation and apoptotic versus necrotic cell death, and the impact of the ensuing sterile inflammatory response. The goal is to enable researchers to select the appropriate model and experimental conditions for testing of natural products that will yield clinically relevant results and allow valid interpretations of the pharmacological mechanisms.

An overview of the evidence and mechanisms of herb-drug interactions

Despite the lack of sufficient information on the safety of herbal products, their use as alternative and/or complementary medicine is globally popular. There is also an increasing interest in medicinal herbs as precursor for pharmacological actives. Of serious concern is the concurrent consumption of herbal products and conventional drugs. Herb-drug interaction (HDI) is the single most important clinical consequence of this practice. Using a structured assessment procedure, the evidence of HDI presents with varying degree of clinical significance. While the potential for HDI for a number of herbal products is inferred from non-human studies, certain HDIs are well established through human studies and documented case reports. Various mechanisms of pharmacokinetic HDI have been identified and include the alteration in the gastrointestinal functions with consequent effects on drug absorption; induction and inhibition of metabolic enzymes and transport proteins; and alteration of renal excretion of drugs and their metabolites. Due to the intrinsic pharmacologic properties of phytochemicals, pharmacodynamic HDIs are also known to occur. The effects could be synergistic, additive, and/or antagonistic. Poor reporting on the part of patients and the inability to promptly identify HDI by health providers are identified as major factors limiting the extensive compilation of clinically relevant HDIs. A general overview and the significance of pharmacokinetic and pharmacodynamic HDI are provided, detailing basic mechanism, and nature of evidence available. An increased level of awareness of HDI is necessary among health professionals and drug discovery scientists. With the increasing number of plant-sourced pharmacological actives, the potential for HDI should always be assessed in the non-clinical safety assessment phase of drug development process. More clinically relevant research is also required in this area as current information on HDI is insufficient for clinical applications.