Table I.

Summary of empirical studies

Authors	Study aims	Design	Sample	Participants	Results
Paxton and Chapple (1996)	To establish the number and kinds of people affected by OTC medicine misuse, medicines involved, pharmacists’ concerns and policies.	Postal questionnaire (no details provided).	All 60 pharmacies in Northumberland, England in 1994.	39 pharmacists (65%) responded.	69% of pharmacists considered there to be some form of OTC medicine misuse in their pharmacies. Female customers were perceived to be more likely to misuse, and Gee’s linctus, codeine linctus or tablets, kaolin and morphine and laxatives were the most commonly cited medicines involved. Most pharmacists had ‘concerns’ about OTC misuse and 62% of pharmacists reported having associated policies including pharmacist interviews, not displaying medicines and refusing sales. Around 2/3 of pharmacies did not communicate with other pharmacies.
Mattoo et al. (1997)	To study socio-demographic and clinical profiled of patients seeking treatment for codeine-based cough medicines in India.	Observational case series; semi-structured interview. No pilot stated.	Patients seeking treatment in hospital addiction centre in Chandigarh in 2004–2005.	All 46 eligible patients identified from the total of 126 opioid abusers participated.	Participants with codeine-based cough medicine dependency were all male, from mainly urban backgrounds (80%) and have completed school education (85%). Initial use was most common through friends (89%) with 11% citing pharmacists or doctors as the source of their supply. Curiosity was the most common reason given for initial use (63%), followed by substitution due to non-availability of another medicine (22%) and treatment of symptoms (15%). Participants reported a range of pleasurable effects, including alertness, cheerfulness and subsequent drowsiness; 92% experienced withdrawal symptoms.
Hughes et al. (1999b)	To investigate the abuse of OTC products in Northern Ireland.	Cross-sectional postal questionnaire. One follow-up mailing piloted, with minor amendments made.	All 509 Northern Ireland community pharmacies in 1997.	253 responses (49.7% response rate).	112 different OTC products identified by pharmacist respondents as being abused in Northern Ireland, with a mean of 6.8 products noted per pharmacist. Opioids were the most common group mentioned (on 878 occasions) and Kaolin & Morphine mixture was the most commonly named product (81.4%, n = 206). Antihistamines were the next most frequently identified (364 times), followed by laxatives. Clients suspected of abusing in the last 3 months ranged from 0 to 700, with a median estimate of 10 and a mode of 6; 55% of such clients were considered regular. No statistical link to pharmacy location and extent of OTC problem. Hiding products, contacting other pharmacies were reported as strategies to deal with the problem and when asked about pharmacists’ role in OTC abuse, 67.2% considered referral to a GP appropriate, 40.3% to a drug and alcohol team appropriate and 64.4% felt pharmacists should be involved in a dedicated harm-reduction programme.
Hughes et al. (1999a)	To assess the attitudes of GPs regarding the appropriateness of OTC medication use by their patients.	Cross-sectional postal survey. No pilot stated.	Stratified random sample of 500 GPs in Northern Ireland. One repeat mailing.	202 GPs responded (40.7%).	Majority of GPs (97%) believed OTC medicines were valuable for self-limiting conditions; 91% were concerned about abuse/misuse potential of OTC medicines; and 73.3% felt these consequences were as severe as prescription problems. Almost 80% of GPs felt they required training in such issues; increased communication between health care professional was identified.
MacFadyen et al. (2001)	To explore the type of OTC medicines being abused and pharmacist attitudes, management and training needs.	Cross-sectional postal survey, 2 reminders and 1 follow-up survey sent in 1998. Survey informed by unreported qualitative study.	All 110 pharmacies in one region of Scotland.	86 responses obtained (79%).	58% reported occasional and 31% frequent misuse, with more problems reported in urban than in rural pharmacies. Perceived prevalence of misuse varied with 45% reporting only 1–2 patients per typical week, 21% reporting 3–4; estimated mean was 5.63. Nytol (79%), laxatives (58%), paracetamol and codeine products (55%) commonest products involved. Frequent requests (100%), counter-assistant concerns (78%), particular products (64%) and suspicious behaviour (45%) identified as alerting factors by pharmacists. Interventions always or often made by 72% of pharmacists, using information provision, removing products from sight, communicating with other pharmacies and medical referrals. More support wanted.
Matheson et al. (2002)	To identify 5-year trends in local misuse of OTC medicines.	Two cross-sectional postal surveys in 1995 and 2000.	1091 and 1162 Scottish community pharmacists.	864 (79.1%) in 1995 and 969 (83.4%) in 2000.	Extent and pattern of misuse unchanged over period – 67.8% (n = 586) in 1995 and 68.5% (n = 669) of pharmacists considered there to be OTC abuse in their area. Nytol remained commonest product and was cited by around half of all pharmacists, then Feminax and Kaolin and morphine. Hiding products, registers of sales, increased pharmacist intervention identified as sales policies.
Pates et al. (2002)	To investigate pharmacist perceptions of OTC misuse, identify products used, alerting factors and strategies used.	Survey of all pharmacies in Welsh health authority in 2000.	180 community pharmacies.	161 (89%) responded.	66% of pharmacists believed there was current OTC misuse, 19% disagreed; mean of 4.5 attempts to misuse OTC product per pharmacy identified in previous month. Opioids most commonly suspected (57%, n = 217), then sleep aids (16%, n = 61) and laxatives (10%, n = 37). Frequency of request (85%, n = 59), customer behaviour/state (11%, n = 18) or appearance (11%, n = 18) identified as alerting factors. Refusals or out of stock excuses commonest strategy (63%, n = 66), then counselling (32%, n = 33). Referral to GP, removing stock, monitoring or limiting sales also mentioned.
McBride et al. (2003)	To explore expert views on OTC abuse, current, future strategies and best practice.	Modified three-stage Delphi design using postal survey.	164 international experts.	109 (66%) recruited and 47 completed all stages.	Consensus reached in key areas such as improving staff training, access to information, and concerns about non-pharmacy and Internet supplies and commercial pressure. Improved coordination and communication essential to implementation. Barriers included staff changes, time pressures, gaining full cooperation, lack of deterrence to those addicted and industry factors.
Myers et al. (2003)	To provide community-level surveillance information of OTC and prescription medicine misuse.	Retrospective study of patients attending substance abuse centres over 6 months periods (1998–2000) using form to collect patient data, drugs used and use patterns.	9063 forms collected from 23 centres in Cape Town, South Africa.	N/A	710 (7.8%) of cases included OTC, prescription or unspecified medicines. Of these, 239 (33.7%) used medicines as primary drug of abuse, and OTC specific use of codeine was identified in 17 cases (29.8%) of these. With 25 (43.9%) being from prescription and 15 (26.3%) being unspecified.
Akram and Roberts (2003)	To determine how pharmacists respond to requests for over-the-counter (OTC) medicines by patients on a methadone maintenance programme.	Cross-sectional postal survey.	All 213 community pharmacists in Glasgow health board, Scotland.	153 of 167 pharmacies providing methadone responded (92%).	Methadone patients sought advice on colds, GI problems and headaches most frequently, and requested codeine/paracetamol analgesics, other analgesics and antacids most frequently. 62% of pharmacists (n = 93) had refused sales, with Nytol (diphenhydramine) the most common, but also codeine-containing analgesics and codeine linctus. Night Nurse, Sudafed and Benylin also denied. 15% (n = 23) of pharmacists had supplied abusable product to avoid problems/trouble. Pharmacists perceived methadone patient requests not to be genuine on occasion.
Fleming et al. (2004)	Develop and pilot a harm-minimisation model for identification and treatment of OTC medicine abuse/misuse by community pharmacists.	Observation of model developed using expert conference discussion local stakeholders consultation; records analysed from participating pharmacies trained in using model.	Two pharmacies.	N/A	18 clients identified during 1 month of pilot (10 in one pharmacy, 8 in the other), of whom 3 were already known to the pharmacist as being suspected of abusing medicines. 14 were challenged and some success reported in initiating change; no clients were successfully enrolled into the harm-minimisation scheme.
Hughes et al. (2004)	To estimate the amount of misuse of and dependence on nicotine gum in OTC setting.	Cross-sectional telephone survey, eliciting views on past and current use of nicotine gum in first study and questions based on dependency diagnostic criteria from DSM-IV and ICD-10. No pilot mentioned.	Public and pharmacy customers in five US states in 2000 approached via adverts.	In first part of study, 351 contacts led to 266 participants. In second study, 139 contacts led to 100 participants.	Around half (46%) of respondents in study 1 had used gum longer than 3 months; 20% of those using gum for more than 90 days attributed use to addiction. In study 2, 66% of respondents met DSM-IV dependency criteria and 74% the ICD-10 criteria. Overall incidence of dependence of nicotine gum was estimated as 0.7–1.4% using data from another study.
Agaba et al. (2004)	Use and abuse of analgesics in Nigeria.	Cross-sectional community survey using structured face-to-face interview. Pretested in pilot.	Two-stage random sampled using residents of Zawan B ward district of Jos, Nigeria.	600 subjects enrolled, but 80 invalid responses.	312 (60%) of participants reported regular (twice a week for 2 months or greater) use of analgesics; 76% obtained by self-medication. Commonest indications were for rheumatical complaints (89%) and headache (67%). Paracetamol commonest medicine (58%), with 28.9% reporting compound analgesic use. Analgesic abuse (defined in study as cumulative lifetime use of > 5000 doses) was identified in 22.6% of participants.
Sweileh et al. (2004)	To obtain information from Palestinian community pharmacists about perceptions of OTC medicine abuse, suspected customer types and solutions.	Questionnaire, section related to demographics and descriptions of customers suspected of abuse.	All 111 pharmacies in Nablus district, Palestine.	97 valid responses obtained.	2/3 of respondents perceived an increase in suspected OTC misuse or abuse due to instability in region, and that majority were not regular customers. 80% of pharmacists identified antitussives as being of misuse/abuse potential, 70% identified analgesics, 41% antihistamine problems and 67% laxative misuse/abuse. Male customers were perceived more likely to abuse or misuse OTC medicines in all categories except laxatives and the 20–40 age range was most commonly identified. Informing the customer’s doctor, hiding products and informing customers of abuse potential were identified as strategies to reduce problem.
Wazaify et al. (2005)	To investigate general public’s opinion and perceptions of OTC medicines.	Cross-sectional survey using structured interviews.	1000 members of public interviewed in 10 shopping centres over 10 weeks in 2002.	N/A	OTC purchases were cited by 11.3% of participants as reason to visit pharmacy. 76.4% of participants reported painkillers as always being kept in stock at home; 14.7% of participants strongly agreed; and 65.2% agreed that some OTC medicines could cause dependency or addition if take over time. Almost 1/3 (n = 298) reported having personally encountered OTC abuse (based on personal experience, knowledge or observation). Younger participants were more likely to report this. Paracetamol (n = 106) was the most reported medicine liable to abuse, followed by Paracodol (n = 37) and co-codamol (n = 30).
Bryant-Waugh et al. (2005)	To determine the availability of laxatives and pharmacists’ and other retailers’ awareness and responses to laxative misuse.	Cross-sectional survey of retailers (pharmacies, supermarkets, health food shops) of laxatives near to eating disorder treatment centre.	293 retailers sent survey by post. No date specified.	53 retailers (18.1%) responded.	20 retailers (37.7%) reported selling laxatives, including all pharmacy respondents but only 1 of 31 conveniences or newsagent categorised retailers. Awareness of abuse potential varied and was not limited only to pharmacies. Only 3 pharmacies had a protocol for supervising sales of laxative, but 18 retailers had at least one policy and these included age restrictions, limiting quantities sold and involving the pharmacist routinely. Responses to suspected misuse involved limiting supply rather than advice.
Wazaify et al. (2006)	To develop a harm-minimisation model for identification and treatment of OTC medicine abuse/misuse by community pharmacists.	Retrospective study of all queries and sales of OTC medicines recognised as having abuse potential (opioid, antihistamine, laxative).	Eight pharmacies in Belfast.	N/A	Over 7 weeks, average of 6.8 clients per pharmacy suspected of abuse, and 4.8 of misuse. Opioids (n = 25), most commonly identified (and were most often requested by male clients), then antihistamines (n = 11) and laxatives (n = 5) (all requested by women). More than half (58.5%) of clients were regarded as strangers rather than regular customers.
Steinman (2006)	To estimate the prevalence of adolescent misuse of OTC drugs, identify misuse of other substances and demographic/psychosocial characteristics of OTC misuse.	Census of students in US county using survey in 2003. Focus groups used to address validity. Frequency of OTC medicine misuse assessed with one question.		39,345 students.	4.7% of students reported misusing OTC drugs occasionally (which included responses to either one or twice a year as used, but not in past year), with a further 2.1% reporting misuse in the previous month. Females misused OTC medicines more than males, as were those who also reported using alcohol and other illicit drugs. Depressive effect and violent behaviour were positively associated with OTC misuse, and Native American youths reported the highest level of OTC misuse, with African Americans reporting the lowest.
Ajuoga et al. (2008)	To investigate the use and misuse of OTC medicine in HIV-infected patients and determine related adverse drug events (ADE).	Cross-sectional self-administered pre-piloted, questionnaire (demographic and attitudinal data) and semi-structured interview (on medicine use, frequency, side effects). Expert panel judged on abuse.	HIV-infected adult patients at Houston, US hospital. Convenient sample of every third clinic patient having prescription filled.	215 patients responded from 338 approached (63.6%).	Analgesics/antipyretic OTC medicines were the most commonly used (64.2%) and non-steriodal anti-inflammatory the most common type. 80 (37.2%) respondents misused OTC medicines on 149 reported occasions, as judged by the panel, by duration (46.3%, n = 69), dose (45.6%, n = 68) and condition (8.1%, n = 12) misuse, respectively. 16.7% (n = 36) of participants reported ADEs.
Orriols et al. (2009)	To explore the feasibility of pharmacoepidemiological methods and to investigate misuse of self-medicated drugs.	Cross-sectional pilot survey of patients requesting medicines from pharmacies assigned into one of five therapeutic groups (codeine, dextromethorphan, pseudoephedrine, antihistamines and control).	74 pharmacies (from 228 solicited in one French region) distributed 817 surveys over 2 months in 2007.	530 participated (64.9%) with 491 valid surveys.	48.9% (n = 240) of patients had used the medicine in previous month, with 49.2% having informed their doctor of such use; 38.8% had started use on medical advice, 27.5% on pharmacist advice. Of those who used codeine-based products in the last month, 15% (8/53) were misusing, 7.5% (4/53) were abusing and 7.5% (4/53) were dependent – all statistically significant. No abuse identified for dextromethorphan, one case for pseudoephedrine, and none for antihistamines.
Björnsdóttir et al. (2009)	Mapping Icelandic people’s definitions of drugs/medicines.	Focus groups.	Members of the public in Iceland, identified as rural/urban dweller, and lay/educated (teaching, ICT, midwifery).	42 participants in 8 focus groups; 4 lay, 5 urban, 4 rural, 4 professional.	Slight variation in definitions of medicines emerged but participants recognised categories such as OTC, prescription, illicit, vitamin/herbal although often chose to conflate drugs as being from any source. Some participants expressed concern about side effects and abuse and misuse potential of medicines, including OTC medicines. More information about medicines was suggested as being needed. The Internet was identified as a source of medicines but rejected, and considered suitable for information in the main.
Nielsen et al. (2010)	To understand who is at risk of developing dependence to OTC codeine, and how products are used.	On-line survey of codeine users, qualitative interviews with codeine-dependent people and key experts.		800 valid survey responses (from 909 respondents), 20 interviews with codeine-dependent people and 14 key experts.	17% (n = 138) survey respondents were codeine-dependent, and around 3/4 had not sought help. Doses at 10 times the recommended maximum were reported. Interviews suggested three types of codeine user: therapeutically dependent on doses not above recommended maximum, recreational users and high-dose-dependent users. Participants viewed OTC medicines as different to other drugs, and themselves as different from other drug users. Key experts perceived older females to be typical, pharmacists used appearance to describe those affected and barriers to treatment involved user’s lack of insight. Raising awareness, training pharmacists and over-coming barriers to treatment recommended.
Albsoul-Younes et al. (2010)	To investigate abuse/misuse of prescription and non-prescription drugs in pharmacies in Jordan.	Cross-sectional survey using structured questionnaire in 2005–2006.	Random sample of 405 pharmacies in Jordan.	N/A	Most respondents (94.1%) suspected some abuse/misuse in their pharmacy, with decongestants, cough/cold products, benzodiazepines and antibiotics most commonly cited. Current controls are ineffective.
Major and Vincze (2010)	Survey self-reported use of OTC medicines and understanding of abuse potential amongst people who visit Hungarian pharmacies.	Structured face-to-face questionnaire of 25 questions. No details given. Piloted with 50.	2000 surveys distributed at 25 geographically varied Hungarian pharmacies in 2008.	1486 completed surveys and 65 returned not valid.	81.7% of respondents thought OTC medicines could be abused and more than half (782) were not able to suggest solutions: 1089 named at least one product or category, 180 named 2 and 45 named 3. Most frequently identified were painkillers, sleep aids and cough medicines. Almost 1/3 of respondents identified specific brands. 536 respondents reported having personally encountered OTC medicine abuse; women were statistically more likely to identify weight loss medicines.
Gonzales et al. (2010)	To examine treatment admission patterns to addiction system for primary abuse of prescription and OTC drugs, differentiating between adolescents and adults.	Cross-sectional descriptive study using data captured for all treatment admissions to public addiction services. Data included drug use and demographic information.	216,716 admissions were identified in this period for individuals aged 12 or over in California, USA, in 2006–2007.	N/A	Prescription and OTC medicines accounted for 6841 (3.2%) of admissions, with adolescents (12–18-year-olds) accounting for 1.5% of overall admissions. OTC medicines represented 1.9% (n = 139) of total of prescribed and OTC medicine admissions and were statistically more likely to be reported by adolescents, who were more likely to cite ‘self’ for referral to treatment than older clients, who cited ‘others’ more often.

Note: OTC, over-the-counter; GP, general practitioner.