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Tuesday, 2 June 2015

2011 The prevalence of herbal medicine home use and concomitant use with pharmaceutical medicines in Jamaica

Journal of Ethnopharmacology
Volume 137, Issue 1, 1 September 2011, Pages 305–311

The prevalence of herbal medicine home use and concomitant use with pharmaceutical medicines in Jamaica


doi:10.1016/j.jep.2011.05.025
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Abstract

Ethnopharmacological relevance

The work described in this paper aimed to study the prevalence of herbal medicine use in treating illness and concomitant use with pharmaceutical medicines in Jamaica.

Materials and methods

A survey using a structured questionnaire was administered by a trained interviewer to randomly selected adults in systematically selected households within randomly selected urban and rural clusters. Categorical data analysis was performed using Stata version 10 software.

Results

91.4% (372/407) of selected people agreed to participate. 72.6% (270/372) self-medicated with herbs within the previous year. Commonly treated were illnesses of the respiratory system (RS, 77.8% (210/270)), gastro-intestinal tract (GIT, 53.3% (144/270)) and health maintenance using tonics (29.6% (80/270)). 26.7% (72/270) of respondents used pharmaceuticals concomitantly with medicinal plants. Commonly treated were illnesses of the RS (20.4% (55/270)), GIT (13.7% (37/270)) and hypertension (10.0%(27/270)). 19.4% (14/72) of physicians knew of such practices. There was significant association of herb use with/without drugs with age (p < 0.001), employment status (p < 0.001), religion (p = 0.004), gender (p = 0.02) and educational level (p = 0.031). Thus prevalence of herb use alone was greatest amongst people aged 35–44 and 45–54 years; those employed; Rastafarians; those without health insurance; males and people who had completed secondary education. Whilst prevalence of concomitant herb–drug use was greater amongst people aged 65 years and older; those retired; those of religions other than Rastafarians and Christians, females and people who had attained primary education and below.

Conclusions

Self-medication with herbs in Jamaica is highly prevalent and highest for self-limiting conditions of the RS, GIT and health maintenance with tonics. Concomitant herb and drug use is highest for self-limiting conditions of the RS, GIT and hypertension, and the use of combined therapy highlights the need for investigations on potential drug–herb interactions. Physicians have limited awareness and knowledge of such concomitant usage, further highlighting the need for increased dialogue with patients, knowledge of medicinal plants and their uses and a heightened pharmacovigilance to avoid adversities that may arise from potential drug–herb interactions.

Graphical abstract

Keywords

  • Polypharmacy;
  • Drug–herb interactions;
  • Adverse drug interactions;
  • Self medication

1. Introduction

Jamaica has a history of reliance on herbal medicine (Asprey and Thornton, 1953, Asprey and Thornton, 1954, Asprey and Thornton, 1955a and Asprey and Thornton, 1955b); with a growing body of medicinal plant research (Mitchell and Ahmad, 2006) and a number of surveys reporting extensive use of herbal teas to date (Landman and Hall, 1983, Michie, 1992, Gardner et al., 2000, Delgoda et al., 2004 and Delgoda et al., 2010). These findings lend support to the World Health Organisation (WHO, 2002) estimate that up to 80% of the population in developing countries use traditional herbal medicine for primary health care. The Beijing Declaration, published by the WHO (2008), calls for a partnership between modern and traditional herbal medicine to help bridge the equity gap in public health and highlights the importance of research to support the development of traditional herbal medicine in delivering appropriate, safe and effective treatments.
Surveys conducted by our laboratories in 2004 (Delgoda et al., 2004) and 2006 (Delgoda et al., 2010) targeted sub-groups of people taking prescription medicines to identify concomitant drug–herb use, a practice known in some instances to contribute to unfavorable interactions leading to possible adverse drug reactions (ADRs). One of the most widely reported cases of an ADR with a herb is that of St. John's wort (SJW) (Hypericum perforatum) with immunosuppressant drug cyclosporin ( Krasowski and Blau, 2011). A number of studies found that concomitant use of SJW and cyclosporin significantly lowered blood concentrations of the drug ( Barone et al., 2000, Breidenbach et al., 2000 and Karliova et al., 2000). SJW has also been shown to lower blood concentrations of the HIV protease inhibitor indinavir and digoxin ( Cheng, 2000 and Piscitelli et al., 2000). ADRs involving drug–herb/nutrient include those with grapefruit juice which is known to inhibit a number of key drug metabolizing enzymes ( Delgoda and Westlake, 2004).
In this latest survey we targeted a wider population in both urban and rural communities in Jamaica to quantitatively identify the prevalence of herbal medicine home use in the treatment of specific illnesses and concomitant use of herbs with pharmaceutical medicines. In reporting the findings of this latest survey we aim to provide health care professionals with information on the use of herbal medicines in primary health care and to launch further laboratory investigations into likely herb–drug interactions, a key aspect of herbal medicine safety.

2. Subjects and methods

In 2008–09 a total of 407 people were invited to participate in a cross-sectional study in three locations, one urban and two rural: Kingston in St. Andrew, Dallas in St. Andrew and Flagstaff in St. James, using a structured questionnaire.
Jamaica is made up of 14 parishes each of which is sub-divided into enumeration districts (EDs). The number of households to be surveyed in each location was established in proportion to the size of that location and the appropriate number of EDs was then randomly selected. Each household was systematically selected and one adult per household was selected at random and interviewed. ED maps, population data and survey guidelines were sourced through the Statistical Institute of Jamaica (STATIN).
Interviews were completed at various times of the day, during the week and at weekends in face-to-face interviews with one interviewer who was trained to avoid bias and to cross examine participants to ascertain reliability of the obtained results.
The survey used a modified TRAMIL questionnaire to gather information on the use of medicinal plants for treatment or prophylaxis of illnesses, details of plant parts used, source of plant material, preparation method, herb combinations, dosages, reason for use, source of knowledge, contraindications, side effects and polypharmacy. TRAMIL (2010) is a Caribbean wide applied research programme and online database that aims to document and scientifically evaluate the efficacy and safety of medicinal plants used for primary health care. Following the TRAMIL methodology a list of the most prevalent health conditions affecting the local population, identified based upon data from the Jamaican Ministry of Health (MOH, 2006), was included in the questionnaire.
Demographic information (number of rooms, numbers of occupants and relationship to interviewee, numbers of children and numbers attending school, years in the area, age, gender, religion, education level attained, reading ability, employment status, health insurance) was collected and interviewees were categorized accordingly.
For the purposes of the study medicinal plants/medicinal herbs/bush medicines were defined as any plant or part of plants used to prepare home remedies and pharmaceutical drugs included both prescription and over-the-counter (OTC) medicines.
In completing interviews, respondent's anonymity was maintained by ensuring that no names, addresses, details of family histories or other details that might identify an individual were recorded, in line with University of the West Indies ethical guidelines.
Plants identified by respondents with medicinal uses were collected during the survey, pressed and identified by Mr. Patrick Lewis, Botanist and Herbarium Curator at the University of the West Indies, Mona, Jamaica.
Data entry utilized Epidata version 3.1 and categorical data analysis was carried out using the statistical package STATA version 10 (StataCorp) to provide measures of frequency and association between variables.

3. Results

Table 1 identifies the characteristics of people interviewed about their use of medicinal plants to treat illness or maintain health in the last 12 months. A total of 407 people were invited to participate in the survey and 91.4% agreed to do so and were included in the study. The study population that indicated their use of medicinal plants to treat illness and maintain health in the previous 12 months was 72.6%.
Table 1. Characteristics of people interviewed about their use of herbal medicine in the last 12 months.
CharacteristicSample size (%)
Interviews
 Completed372 (91.4)
 Declined35 (8.6)
Used herbal medicine to treat illness or maintain health in last 12 months
 Yes270 (72.6)
 No102 (27.4)
Where respondent had not used herbal medicine the main reason stated was
 Lack of knowledge27 (26.5)
 Think it is unsafe, doctors are safer20 (19.6)
 Never needed to15 (14.7)
 Do not know13 (12.7)
 Just use as tea (not for medicinal purpose)27 (26.5)
Table options
Respondents who had not specifically used medicinal plants to treat illness or maintain health in the last 12 months cited a number of reasons such as lack of knowledge and safety concerns. 26.5% indicated that they had used medicinal plants ‘just as teas’ but not to treat illness or maintain health and were therefore not included in the survey.
Table 2 and Table 3 give demographic and socioeconomic details, respectively, for the study group. There was significant association of herb use with/without drugs with age (p < 0.001) and employment status (p < 0.001). Prevalence of herb use alone was lowest in people aged 65 years and older and highest in 35–44 and 45–54 year-olds whilst concomitant herb–drug use was highest in people aged 65 years and older and lowest in 18–24 year-olds.
Table 2. Sample size and in bracket prevalence (%) of non herb use, herb use only and concomitant herb–drug use in demographic groups and percent (%) distribution of socio-demographic groups in study sample.
Demographic indexNon herb useHerb use aloneHerb & drug useTotal
Residence
 Rural62 (24.1)139 (54.1)56 (21.8)257 (69.1)
 Urban40 (34.8)59 (51.3)16 (13.9)115 (30.9)
Age group (years)
 18–2416 (36.4)26 (59.1)2 (4.5)44 (11.9)
 25–3421 (28.4)42 (56.8)11 (14.8)74 (19.9)
 35–4417 (26.1)41 (63.1)7 (10.8)65 (17.5)
 45–5412 (17.4)45 (65.2)12 (17.4)69 (18.6)
 55–6417 (35.4)21 (43.8)10 (20.8)48 (12.9)
 65–749 (25.7)11 (31.4)15 (42.9)35 (9.4)
 ≥7510 (27.8)11 (30.5)15 (41.7)36 (9.7)
Gender
 Female72 (31.2)110 (47.6)49 (21.2)231 (62.1)
 Male30 (21.3)88 (62.4)23 (16.3)141 (37.9)
Religion
 Christian81 (27.5)150 (51.0)63 (21.4)294 (79.2)
 Rastafarian1 (4.8)18 (85.7)2 (9.5)21 (5.7)
 Other4 (50.0)1 (12.5)3 (37.5)8 (2.2)
 None16 (33.3)28 (58.3)4 (8.3)48 (12.9)

Total102 (27.4)198 (53.2)72 (19.3)372
Table options
Table 3. Sample size and in bracket prevalence (%) of non herb use, herb use alone, concomitant herb–drug use and total response in socio-economic groups and percent (%) distribution of socio-economic groups in study sample.
Socioeconomic indexNon herb useHerb use aloneHerb & drug useTotal
Education level
 Primary or lower21 (25.6)40 (48.8)21 (25.6)82 (23.0)
 Secondary58 (24.8)136 (58.12)40 (17.1)234 (65.7)
 Post-secondary18 (45)17 (42.5)5 (12.5)40 (11.2)
Reading level



 Good61 (27.4)125 (56.0)37 (16.6)223 (60.9)
 Fair20 (27.0)38 (51.4)16 (21.6)74 (20.2)
 Poor13 (27.1)24 (50.0)11 (22.9)48 (13.1)
 Cannot read6 (28.6)9 (42.9)6 (28.6)21 (5.7)
Occupational field
 Business42 (28.0)83 (55.3)25 (16.7)150 (45.3)
 Health, science8 (32.0)8 (32.0)9 (36.0)25 (7.5)
 Ed.Agr, tran, sec20 (21.3)58 (61.7)16 (17.0)94 (28.4)
 Domestic8 (22.9)23 (65.7)4 (11.4)35 (10.6)
 Other9 (33.3)12 (44.4)6 (22.2)27 (8.2)
Employment status
 Employed F/T45 (25.8)107 (61.5)22 (12.6)174 (46.9)
 Employed P/T6 (23.1)17 (65.4)3 (11.5)26 (7.0)
 Unemployed32 (32.3)49 (49.5)18 (18.2)99 (26.7)
 Retired14 (22.6)19 (30.6)29 (46.8)62 (16.7)
 Student5 (50.0)5 (50.0)0 (0.0)10 (2.7)
Health insurance
 Yes27 (41.5)24 (36.9)14 (21.5)65 (17.5)
 No75 (24.4)174 (56.7)58 (18.9)307 (82.5)
Crowding index
 Yes51 (24.5)119 (57.2)38 (18.3)208 (57.3)
 No49 (31.6)73 (47.1)33 (21.3)155 (42.7)

Total10019271372
Table options
Prevalence of herb use alone was lowest amongst the retired and highest amongst those employed whilst concomitant herb–drug use was highest in the retired and lowest in students.
There was also statistically significant association of herb use with educational level (p = 0.031), gender (p = 0.02), possession of health insurance (p = 0.007) and religion (p = 0.004).
Prevalence of herb use alone was lowest in those with tertiary education and highest in those who had completed secondary education whilst concomitant herb–drug use was highest in those with education up to primary level or below and lowest in those with tertiary education.
Prevalence of herb use alone was highest amongst male respondents, those without health insurance and Rastafarians whilst prevalence of concomitant herb–drug use was highest amongst female respondents and those of other religions.
Area of residence (urban/rural), reading level, occupation and household crowding were not significant correlates of medicinal plant use alone or with pharmaceutical drugs.
Thus prevalence of herb use alone was greatest amongst people aged 35–44 and 45–54 years; those employed; people who had completed secondary education; males; Rastafarians and those without health insurance (Table 2 and Table 3). Whilst the prevalence of concomitant herb–drug use was greater amongst people aged 65 years and older; those retired; people who had attained primary education and below; females and those of other religions.
Table 4 details the body systems and health conditions treated with medicinal plants alone and concomitantly with pharmaceutical drugs within the study sample. The conditions most commonly identified were self limiting illnesses of the respiratory system (RS) and gastro-intestinal tract (GI tract), and the maintenance of health using herbal tonics. Within the study sample, more than a quarter of respondents indicated their concomitant use of medicinal plants with pharmaceutical drugs with the most commonly self-medicated conditions for this sub-population being illnesses of the RS, GI tract and hypertension. The concomitant use of medicinal plants and pharmaceutical drugs was not limited to treatments for the same condition for example a respondent might take a pharmaceutical drug for hypertension and also self medicate with medicinal plants for a cold or bellyache.
Table 4. Number of individuals and in bracket prevalence (%) of herb use for treating specified illnesses with herbs alone, herbs together with drugs and percent (%) distribution of reported illnesses treated with herbs in the study sample (n = 270).
Popular use or disease treatedHerb onlyHerb & drugaTotal herb use
Respiratory system (asthma, cold/flu/sore throat/cough, cold in belly, sinusitis)155 (57.4)55 (20.4)210 (77.8)
GI tract (diarrhea, constipation, vomiting, bellyache/gas, ulcer, hemorrhoid, worms)107 (39.6)37 (13.7)144 (53.3)
Tonic (washout & blood cleanse)63 (23.3)17 (6.3)80 (29.6)
Hypertensionb15 (5.5)27 (10.0)42 (15.5)
Musculoskeletal (arthritis, backache, sprain)27 (10.0)12 (4.4)39 (14.4)
Mental health (insomnia, nerves, depression)26 (9.6)9 (3.3)35 (13.0)
Headache22 (8.14)4 (1.5)26 (9.6)
Skin (rash, fungal infection, acne)21 (7.8)5 (1.8)26 (9.6)
Gynecological (menstrual problems, fibroids, infertility, infection)9 (3.3)6 (2.2)15 (5.5)
Cardiovascular system (high cholesterol, peripheral vascular disease, heart valve disease, coronary heart disease)4 (1.5)9 (3.3)13 (4.8)
Diabetes (type II)4 (1.5)8 (3.0)12 (4.4)
Injury (burn, wound/cut/bruise)8 (2.9)2 (0.7)10 (3.7)
Genito-urinary (bladder, cystitis)5 (1.8)3 (1.1)8 (3.0)
Prostate problems3 (1.1)2 (0.7)5 (1.8)
Teeth (teething, toothache)3 (1.1)1 (0.4)4 (1.5)
Eyes3 (1.1)1 (0.4)4 (1.5)
a
N.B. drug use is not limited to drugs taken for the same condition being treated by herbs.
b
Hypertension listed separately from cardiovascular disease due to high level of prevalence.
Table options
Respondents across the three locations identified their use of 116 different medicinal plants in the previous 12 months. Table 5 lists the top 50 with the most frequently cited being Momordica charantia (Cerasee), Bryophyllum pinnatum (Leaf of Life), Aloe vera (Sinkle Bible) and Eupatorium odoratum (Jack-in-the-Bush).
Table 5. The top fifty medicinal plants most commonly used by herbal medicine users (n = 270), ranked by prevalence.
Scientific nameFamilyLocal namen%
Momordica charantia L.CucurbitaceaeCerasee11442.2
Bryophyllum pinnatum (Lam.) OkenCrassulaceaeLeaf of Life9334.4
Aloe vera (L.) Burm. f.XanthorrhoeaceaeSinkle Bible6825.2
Eupatorium odoratum L.AsteraceaeJack-in-the-Bush6122.6
Annona muricata L.AnnonaceaeSoursop4115.2
Zingiber officinale RoscoeZingiberaceaeGinger3713.7
Solanum torvum Sw.SolanaceaeSusumber3513.0
Allium sativum L.AmaryllidaceaeGarlic3412.6
Piper amalago L.PiperaceaeJointer2810.4
Gliricidia sepium (Jacq.) Kunth ex Walp.FabaceaeMaranga2710.0
Stachytarpheta jamaicensis Hutch. & DalzielVerbenaceaeVervine269.6
Clerodendrum thomsoniae Balf.LamiaceaeRice & Peas259.3
Andrographis paniculata (Burm. f.) NeesAcanthaceaeRice Bitters248.9
Rivina humilis L.PhytolaccaceaeDogblood228.2
Morinda citrifolia HunterRubiaceaeNoni217.8
Opuntia cochenillifera (L.) Mill.CactaceaeTuna207.4
Polyscias guilfoylei (W. Bull) L.H. BaileyAraliaceaeAralia197.0
Cymbopogon citratus (DC.) StapfPoaceaeFever Grass165.9
Chenopodium ambrosioides L.AmaranthaceaeSemicontract155.6
Rhytidophyllum tomentosum (L.) Mart.GesneriaceaeSearch-mi-Heart155.6
Bidens reptans (L.) G. DonAsteraceaeMarigold134.8
Petiveria alliacea L.PhytolaccaceaeGuinea Hen Weed134.8
Desmodium canum Schinz & Thell.FabaceaeStrongback114.1
Priva lappulacea (L.) Pers.VerbenaceaeFasten-pon-coat114.1
Citrus aurantiifolia (Christm.) SwingleRustaceaeLime93.3
Hyptis verticillata Jacq.LamiaceaeJohn Charles93.3
Picramnia antidesma Sw.PicramniaceaeMajoe Bitters93.3
Artocarpus altilis (Parkinson) FosbergMoraceaeBread Fruit83.0
Cassia alata L.FabaceaeKing of the Forest83.0
Bambusa vulgaris Wendl. ex NeesPoaceaeBamboo72.6
Lippia alba (Mill.) N.E. Br. ex Britton & P. WilsonVerbenaceaeColic Mint72.6
Picrasma excelsa (Sw.) Planch.SimaroubaceaeBitter Wood72.6
Pothomorphe umbellata (L.) Miq.PiperaceaeCowfoot72.6
Bidens pilosa L.AsteraceaeSpanish Needle62.2
Cassia occidentalis L.FabaceaeDandelion62.2
Mentha × piperita L.LamiaceaePeppermint62.2
Pimenta spp. Lindl.MyrtaceaePimento62.2
Pseudelephantopus spicatus (Juss. ex Aubl.) C.F. BakerAsteraceaeDog Tongue62.2
Smilax spp. L.SmilacaceaeSarsaparilla62.2
Argemone mexicana L.PapaveraceaeThistle51.9
Mikania micrantha KunthAsteraceaeQuaco Bush51.9
Psidium guajava L.MyrtaceaeGuava51.9
Terminalia catappa L.CombretaceaeAlmond51.9
Achyranthes indica (L.) Mill.AmarantaceaeDevil's Horsewhip41.5
Alysicarpus vaginalis (L.) DC.FabiaceaeMedina41.5
Cannabis sativa L.CannabaceaeGanja41.5
Cecropia peltata L.UrticaceaeTrumpet Tree41.5
Cola acuminata (P. Beauv.) Schott & Endl.MalvaceaeBissy41.5
Cordia globosa (Jacq.) KunthBoraginaceaeBlack Sage41.5
Justicia pectoralis Jacq.AcanthaceaeFresh Cut41.5
Table options
Table 6 identifies characteristics of the sub-population of concomitant herb–drug users with 26.7% identifying their use of medicinal plants concomitantly with pharmaceutical drugs in the previous 12 months. Only 19.4% indicated that their medical practitioner was aware of their use of herbs with only a fraction stating that they were asked if they used herbs by the practitioner.
Table 6. Characteristics of people engaging in concomitant use of herbs and pharmaceutical drugs (n = 72), ranked by prevalence.
Characteristicn%
Medical practitioner is aware of the use of herbs1419.4
Medical practitioner asked whether herbs were used79.7
Reasons given for the concomitant use of herbs and medicines
 They work well together912.5
 Pharmaceutical drug alone not good45.5
 Too many side effects with pharmaceutical drug68.3
 Pharmaceutical drug expensive811.1
 No harm in taking both together811.1
 Not taking pharmaceutical drug for same condition3548.6
Has experienced side effects from the practice of polypharmacy00.0
Who would side effects, if any, be reported to
 Doctor2534.7
 Nurse68.3
 Family member11.4
Table options
When asked why they used herbs with pharmaceutical drugs nearly half of respondents indicated that they were not using them for the same condition. Other reasons cited included that they worked well together, there was no harm in taking both together, pharmaceutical drugs were too expensive, pharmaceutical drugs had too many side effects and that pharmaceutical drugs alone were no good.
None of the respondents reported experiencing side effects when taking drugs and herbs together. However if side effects were to be experienced a third of respondents stated that they would prefer to tell their doctor. 16.7% stated that if given the choice they would choose an herbal medicine rather than a prescription drug.
A majority of concomitant herb–drug users were able to identify the pharmaceutical drugs they had taken with herbs in the previous 12 months (Table 7). Some of the most common drugs cited included hydrochlorothiazide (HZT) for hypertension and fluid retention, metformin for diabetes, salbutamol (Ventolin) for bronchospasm and enalapril for hypertension and obstructive heart failure.
Table 7. Pharmaceutical drugs taken by respondents (n = 72), ranked by prevalence and associated medicinal plants taken concomitantly.
Pharmaceutical drugn%Medicinal plant (common namea)
Hydrochlorothiazide (HZT)1013.9Almond, Aralia, Barsley, Cerasee, Chicken Weed, Cow's Tongue, Coconut, Dandelion, Fasten-pon-coat, Ginger, Jack-in-the-Bush, Jackie Saddle, John Charles, Maranga, Noni, Jointer, Peppermint, Pimento, Rice Bitters, Rosemary, Sarsaparilla, Sinkle Bible, Soursop, Vervine
Metformin1013.9Barsley, Bissy, Cerasee, Chicken Weed, Colic Mint, Dandelion, Fevergrass, Garlic, Jack-in-the-Bush, John Charles, Maranga, Noni, Rice Bitters, Rice & Peas, Search-mi-heart, Sinkle Bible, Soursop, Susumber, Tuna
Salbutamol (Ventolin)912.5Aralia, Breadfruit, Cerasee, Dogblood, Fresh Cut, Garlic, Jack-in-the-Bush, Leaf of Life, Maranga, Jointer, Rice & Peas, Seaweed, Sinkle Bible, Soursop, Susumber, Vervine,
Enalapril68.3Cerasee, Chicken Weed, Ginger, Jack-in-the-Bush, Leaf of Life, Maranga, Noni, Sarsaparilla, Search-mi-heart, Vervine
Aspirin56.9Aralia, Cerasee, Fasten-pon-coat, Fever Grass, Ginger, Garlic, Jack-in-the-Bush, John Charles, Leaf of Life, Maranga, Sinkle Bible, Soursop, Tuna
Simvastatin45.5Breadfruit, Cerasee, Jack-in-the-Bush, Marigold, Maranga, Pear, Search-mi-heart, Spanish Needle, Susumber, Thistle
Atenolol34.2Fever Grass, Jack-in-the-Bush, Noni, Maranga, Soursop
Furosemide34.2Cerasee, Ginger, Jack-in-the-Bush, Leaf of life, Sarsaparilla, Search-mi-heart, Vervine
Hydralazine34.2Aralia, Jointer, Fever Grass, Garlic, Ginger, John Charles, Leaf of Life, Sinkle Bible, Soursop, Susumber, Trumpet Tree
Nifedipine34.2Breadfruit, Fasten-pon-coat, Garlic, Ginger, Jack-in-the-Bush, Leaf of Life, Marigold, Maranga, Pear, Jointer, Search-mi-heart, Spanish Needle, Rice & Peas, Sinkle Bible, Susumber, Tuna
Atorvastatin (Lipitor)22.8Dogblood, Noni
Bendroflumethiazide & reserpine22.8Fasten-pon-coat, Garlic, Leaf of Life, Rice & Peas, Sinkle Bible, Soursop, Susumber, Tuna
Captopril22.8Breadfruit, Garlic, Jack-in-the-Bush, Marigold, Maranga, Pear, Search-mi-heart, Sinkle Bible, Soursop, Spanish Needle
Carvedilol (Talliton)22.8Ginger, Leaf of Life, Jointer, Sarsaparilla, Sinkle Bible, Strongback
Loratadine (Claritin)22.8Cerasee, Leaf of Life, Search-mi-heart
Diclofenac22.8Dogblood, Jack-in-the-Bush, Maranga, Noni, Susumber, Thistle
Digoxin (Lanoxin)22.8Cerasee, Ginger, Jack-in-the-Bush, Leaf of life, Sarsaparilla
Gliclazide (Diamicron)22.8Cerasee, Chicken Weed
Glyburide (Glynase)22.8Barsley, Cerasee, Chicken Weed, Dandelion, Golden Seal, Noni, Rice Bitters, Sinkle Bible
Ibuprofen22.8Cerasee, Jack-in-the-Bush, Leaf of Life, Peppermint, Semi-contract, Sinkle Bible, Tuna, Vervine
Piroxicam (Feldene)22.8Cerasee, Dogblood, Garlic, Jointer, Rice & Peas, Susumber
Ranitidine22.8Cerasee, Garlic, Ginger, Leaf of Life, Maranga, Sarsaparilla, Tuna
a
Scientific names of medicinal plants not listed in Table 5 include: Barsley = Ocimum campechianum; Chicken Weed = Salvia serotina; Coconut = Cocus mucifera; Cow's Tongue = Polypodium phyllitidis; Jackie Saddle = Peperomia amplexicaulis; Pear = Persea americana; Rosemary = Rosmarinus officinalis.
N.B. medicinal plants taken for the same condition as a pharmaceutical drug are highlighted in bold.
Table options
Over a third of concomitant herb–drug users stated that they took pharmaceutical drugs and herbs within hours of each other whilst nearly two thirds alternated each type on different days. Nearly half of the respondents took medicinal plants for the same condition as at least one of the pharmaceutical drugs taken and these plants are highlighted in bold type in Table 7. For example some respondents who took metformin for diabetes also indicated that they self medicated with Cerasee, Chicken Weed, Noni, Rice Bitters, Sinkle Bible and Tuna for the same condition. Commonly used combinations of pharmaceutical drugs and herbs, taken for the same condition, were metformin hydrochloride with cerasee and sinkle bible, hydrochlorothiazide (HZT) with Noni and salbutamol (Ventolin) with garlic.

4. Discussion

This survey was the first to be carried out on households, targeting a population of herbal medicine users on their practices of herb–drug concomitant use in Jamaica. A previous survey by our laboratory reported on medicinal plant use within a population of pharmaceutical drug users for any ailment (Delgoda et al., 2010) and specifically for diabetes, hypertension and GI tract infections (Delgoda et al., 2004). In this latest study we report the prevalence of concomitant herb–drug use in this population of home users as 26.7%. It is interesting to note that in this latest survey and a recent survey (Delgoda et al., 2010), no statistically significant difference was seen in medicinal plant use between urban and rural respondents. This contrasts with two previous surveys (Gardner et al., 2000 and Delgoda et al., 2004).
Results from our latest survey reveal that respondents, who had little or no schooling, were retired and aged 65 years or older, demonstrated a greater tendency to practice concomitant herb–drug use. This contrasts with findings in the population of pharmaceutical drug users (Delgoda et al., 2010) where concomitant herb–drug use, amongst those with no schooling, was comparable to those with tertiary education and was not found to be linked significantly with employment status or age. Concomitant herb–drug use in the elderly raises particular concern about possible adverse drug reactions (ADRs) resulting from herb–drug interactions. A meta-analysis of 68 observational studies in the UK reported that ADR-related hospitalisations, resulting from drug–drug interactions, are four times higher in older than in younger patients and may account for as many as 17% of elderly admissions. The authors of the report go on to suggest that the majority of these admissions are preventable as they result from predictable drug interactions (Beijer and de Blaey, 2002). In Australia repeat ADR-related hospitalisations in the elderly account for up to a third of events (Zhang et al., 2007).
Pharmacodynamic changes in old age lead to increased complexity of interactions between polypharmacy, co-morbidity, altered pharmacokinetics and pharmacodynamic sensitivity. In addition, due to age related chronic diseases and the increased prescription of prophylactic drugs those aged 65 and over receive a disproportionate number of drugs (Wynne and Blagburn, 2010), for example in the UK, 45% of total prescriptions dispensed (Department of Health, 2004). In the over 65s multiple medication use has been identified as a major contributor to the development of potentially serious ADRs (Haider et al., 2009, Stegemann et al., 2010, Steinman and Hanlon, 2010 and Wynne and Blagburn, 2010).
Hypertension in Jamaica is the seventh leading cause of death in the general population but the fourth in those aged 60 years old and over (MOH, 2006). In the sub-population of concomitant herb–drug user hypertension was identified as the third most commonly self-medicated condition and in addition six of the ten pharmaceutical drugs most commonly prescribed were for hypertension. In the UK, cardiovascular drugs are amongst those most implicated in ADRs in the elderly (Pirmohamed et al., 2004 and Patel et al., 2007).
Herbs taken for hypertension concomitantly with antihypertensive drugs included: garlic with hydralazine, nifedipine, bendroflumethiazide/reserpine and captopril; pear leaf and breadfruit leaf with nifedipine and captopril. Two of these antihypertensive drugs are known to be metabolized by human CYP450 enzymes; nifedipine is metabolized by CYP3A4 and captopril by CYP2D6. To date, in vitro and in vivo studies on the drug interactions of garlic have yielded contradictory results indicating both possible inhibition and induction of CYP3A4. Clinical investigations have identified a number of potential pharmacokinetic interactions, highlighting the need for patients taking drugs that are CYP3A4 substrates to be monitored when there is concomitant use with garlic ( Colalto, 2010). Preliminary in vitro work has identified potential inhibition of CYP3A4 by pear leaf ( Agbonon et al., 2010). Given the already high risk of drug–drug interactions in the elderly it is clear that research is urgently required to screen commonly used medicinal plants to reduce the risks of potential herb–drug interactions. In vitro laboratory investigations are currently underway in our laboratory using human CYP450 enzymes to investigate the potential for herb–drug interactions in some of the most commonly used Jamaican medicinal plants and the key phytochemicals identified from them ( Shields et al., 2008 and Badal et al., 2011).
In reviewing the perceived safety of concomitant herb–drug use there is significant difference between the sub-population of herb–drug users in this latest survey and the pharmaceutical drug users previously surveyed. Delgoda et al. (2010) reported that the overwhelming majority of respondents did not consider the concomitant use of both types of medicine to be harmful. In this latest survey the response was far less clear with 48.6% of respondents indicating that the medicinal plants used were not taken for the same condition. This appears to indicate a perception that if the two types of medicine are taken together for different illnesses they are unlikely to interact and are therefore safe. However 59% of concomitant herb–drug users indicated some awareness of the possible dangers stating that they alternated the days on which they took the two types of medicine compared to 39% who took both on the same day. Whilst some awareness of the potential dangers is clear, the level of understanding is low. Alternating the days may not be sufficient time to avoid potential interaction given that different drugs take different periods for clearance which can vary from several hours to several days.
The level of underreporting to physicians of concomitant herb–drug use in this latest survey (19.4%) is similar to that reported in a number of studies (Bristol et al., 2008): 28% of patients in one study (Cockayne et al., 2005) and 23% in another (Robinson and McGrail, 2004). Reasons cited for non-disclosure were expectation of a negative reaction from the doctor, the perception that there was no need to report such use and the fact that they were simply not asked (Robinson and McGrail, 2004). Physician awareness of concomitant herb–drug use and the percentage of physicians proactively asking patients are in line with two previous surveys in Jamaica (Delgoda et al., 2004 and Delgoda et al., 2010). Research in neighbouring Trinidad and Tobago (Clement et al., 2005 and Clement, 2009), previously cited by Delgoda et al. (2010) revealed a higher percentage of physicians asking their patients about their use of herbs. Physicians were found to be more accepting of herbal medicine use in their patients but exhibited poor knowledge of herbs leading to a gap in communication. The level of concomitant herb–drug use reported in primary care centres at 29% was close to that reported in our sub population of concomitant herb–drug users (25.9%) (Clement et al., 2005 and Clement, 2009).
This study is not without limitation. Some degree of bias may have been introduced if selection of subjects had been limited to a particular time or day of the week despite efforts to interview at different times and days of the week. Estimates may have been subjected to recall bias if people had problems recalling herbs and pharmaceutical drugs prior to interview.

5. Conclusion

This latest survey shows that self medication with medicinal plants continues to be highly prevalent in Jamaica (72.6%) and is highest for conditions of the respiratory system, gastro-intestinal tract and health maintenance. Concomitant herb–drug use is highest for conditions of the respiratory system, gastro-intestinal tract and hypertension. Such concomitant use is most prevalent in the retired and those aged over 65 years; amongst those who have had primary education or below, and contrary to common belief, was independent of whether the respondent lived in a rural or urban location. Physicians’ awareness of herb drug co-use was particularly low (19.4%) and draws attention to the fact that there exists a gap in communication between patient and physician in relation to self medication with herbs. With a practice of co-medication, there exists the possibility for drug–herb interactions and information gathered in this survey will help initiate laboratory based investigations for those combinations that may lead to potential adverse drug reactions. Herbs found to be used in combination with drugs in this study, will undergo screens for potential CYP450 enzyme mediated pharmacokinetic interactions. A better understanding of herb pharmacokinetics is an aspect of herb safety with the potential to increase physician awareness and knowledge and to enable greater integration into Jamaica's national healthcare system, in line with the 2008 Beijing Declaration that calls for a partnership between modern and traditional medicine to help bridge the equity gap in public health.

Acknowledgements

We thank the Commonwealth Scholarship Commission, the University of the West Indies Postgraduate Research Fund, the Environmental Foundation of Jamaica, the Forest Conservation Fund and the International Foundation for Science (Sweden) for funding support.The authors express their gratitude to respondents who so graciously gave their time and generously shared their traditional knowledge during the survey. We thank and acknowledge the hard work and dedication of Devon Lindsay who helped coordinate and manage the survey across the three areas. Community leaders and others for facilitating the surveys, guidance in their areas and botanical collection: Kelvin Clarke, Mike Grizzle the late Mr Black, Melinda Brown, Dolphy Powell, Mr Dallas and Garfield McNaughton.

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Corresponding author at: Natural Products Institute, Faculty of Pure and Applied Sciences, University of the West Indies, Mona, Jamaica. Tel.: +876 9702574; fax: +876 9702574.
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