Pharmacist Advice Research Articles

Characteristics of drug-related problems discussed by hospital pharmacists in multidisciplinary teams

To investigate pharmacist contribution in the therapeutic hospital team by studying drug-related problems (DRPs), pharmacist therapy advice and consequences of the advice. From May to December 2002, 827 patients in five Norwegian hospitals were included in the study. Demographic data, drugs used, relevant medical history, laboratory data and clinical/pharmacological risk factors were recorded prospectively at the wards. DRPs, patients characteristics, pharmacist advice to physicians, nurses or patients, response to the pharmacist advice, and reasons (stated by the pharmacist) for not discussing an identified DRP, were reported. An independent quality assessment team retrospectively assessed the DRPs for a randomly selected number of the study population. On average 2.6 DRPs per patient were found. A total of 2128 DRPs were registered and of these 1583 (74%) DRPs were brought up for discussion. Physician immediate acceptance rates varied from 80% (for extremely important clinically significant DRPs) to 50% (for DRPs of minor clinical significance). High age, use of many drugs at admission, existence of many DRPs and many clinical/pharmacological risk factors for DRPs were associated with low immediate acceptance rate. Type of DRP influenced how the DRP was discussed; adverse drug reaction (ADR) and unnecessary drug were discussed with physicians while e.g. medical chart error and need for patient education were discussed with nurses/patients. Reasons for not discussing DRPs in the team were: not given priority (37%), no longer relevant (31%) and others (31%). DRPs of minor clinical significance were most often excluded from discussion (37%) as opposed to 14% and 22% of those of moderate and major clinical significance. The majority of patients had one or more DRPs. The problems identified as DRPs by the pharmacists were accepted as such by the physicians and to a high degree acted upon. Both clinical significance of the DRP and patient characteristics influenced physician immediate acceptance rate. Some DRPs could be solved by direct contact with nurses or the patients. Awareness of DRPs increases through participation of pharmacists in the multidisciplinary therapeutic hospital team.

Canadian Cardiovascular Society consensus conference recommendations on heart failure 2006: Diagnosis and management

Heart failure remains a common diagnosis, especially in older individuals. It continues to be associated with significant morbidity and mortality, but major advances in both diagnosis and management have occurred and will continue to improve symptoms and other outcomes in patients. The Canadian Cardiovascular Society published its first consensus conference recommendations on the diagnosis and management of heart failure in 1994, followed by two brief updates, and reconvened this consensus conference to provide a comprehensive review of current knowledge and management strategies. New clinical trial evidence and meta-analyses were critically reviewed by a multidisciplinary primary panel who developed both recommendations and practical tips, which were reviewed by a secondary panel. The resulting document is intended to provide practical advice for specialists, family physicians, nurses, pharmacists and others who are involved in the care of heart failure patients. Management of heart failure begins with an accurate diagnosis, and requires rational combination drug therapy, individualization of care for each patient (based on their symptoms, clinical presentation and disease severity), appropriate mechanical interventions including revascularization and devices, collaborative efforts among health care professionals, and education and cooperation of the patient and their immediate caregivers. The goal is to translate best evidence-based therapies into clinical practice with a measureable impact on the health of heart failure patients in Canada.

Book Review: Practical Chemotherapy: A Multidisciplinary Guide. Summerhayes and Daniels

This book represents a series of short monographs on cytotoxic drugs that are commonly used singly or in combination in oncology. The authors are quite clear in their introduction that the text does not provide a comprehensive account of cancer chemotherapy in the hope that this will avoid disappointment for readers who are looking for such a volume. In essence, they have produced a recipe book of 65 single agent and combination regimens that are widely in use and have supplemented this information with specific advice for prescribers, nurses and pharmacists. As such, this approach allows for rapid access to useful information by each of these groups on most of the commonly used drug cocktails. They are to be congratulated on the fact that the volume includes data on some of the newer agents, such as trastuzumab (Herceptin) and rituximab), that have entered the pharmacopoeia in recent years. In each section there is important information on drug administration and emetogenicity of treatment. There are a number of useful hints for prescribers, nurses and pharmacists that are aimed at avoiding some of the more commonly occurring avoidable complications of cytotoxic drug administration. The authors have attempted to ensure that the information in each section is self-contained with minimal requirement for cross-referencing throughout the rest of the book. While this fact may be seen as a specific strength of the text and may make it useful for occasional reference on a specific regimen that is infrequently used, it also leads to extensive repetition of material. To cite just one example of this tendency, the Cockcroft-Gault formula for calculating creatinine clearance is described in 8 separate places in the first 100 pages of the book and this rate of repetition does not slacken in the rest of the text. Indeed, in each of the regimens where a platinum drug is used there is essentially the same page of text to describe the effects of platins on the renal tract and the need for monitoring. This compartmentalisation of the text detracts from the overall effect and gives the book a feeling of a collection of data sheets rather than the multidisciplinary guide book advertised in the title. I fear that by adopting this approach the authors have ensured that this book will largely be consigned to use as a reference manual in cytotoxic pharmacies and on chemotherapy day units. I doubt that this will be seen as an important acquisition for hospital libraries or oncology departments.

Community pharmacy supply of emergency hormonal contraception: a structured literature review of international evidence

We could find no previous published review of the evidence relating to pharmacy supply of emergency hormonal contraception (EHC). Our objectives were to review, summarize and evaluate the peer-reviewed evidence relating to community pharmacy supply of EHC both in the UK and internationally. Systematic searches were conducted for peer-reviewed international research from January 1990 to January 2005. The UK Health Development Agency's Evidence Base 2000 standards and the evidence categories used by the UK Department of Health were applied to each paper. We included 24 peer-reviewed papers. There was one randomized controlled trial (RCT); the remainder of the studies were qualitative or observational studies. Pharmacy supply of EHC enables most women to receive it within 24 h of unprotected sexual intercourse. Services were highly rated by women. One RCT showed that improving access to EHC did not reduce the use of other contraceptives, lead to an increase in risky sexual behaviour or increase the incidence of sexually transmitted infections (STIs). Users expressed some concerns about the appropriateness of receiving additional pharmacist advice regarding future contraception use and STIs. One study found pharmacy supply had led to a decrease in attendances at accident and emergency departments. There is good evidence that community pharmacy EHC services provide timely access to treatment and are highly rated by women.

What role do community pharmacists currently play in the management of headache? A hospital-based perspective.

Of one hundred consecutive patients with headache referred by general practitioners to general neurology outpatient clinics, only 15 had at any time consulted a community pharmacist for advice about headache or its treatment; none spontaneously volunteered this information. Community pharmacists may represent an underused resource in the management of headaches in primary care, but would require specific training to fulfil such a role.

Prevalência da automedicação na população urbana portuguesa

Este estudo transversal teve como objetivo principal determinar a prevalência da automedicação em meio urbano. Decorreu nas cidades de Lisboa e Porto, respectivamente em 11 e 15 farmácias, no período de Novembro de 1995 a Setembro de 1996. A recolha de informação dividiu-se em 6 fases de 10 dias cada. A prevalência da automedicação encontrada foi de 26,2%. Encontraram-se diferenças estatisticamente significativas no que respeita às prevalências da automedicação por sexo, idade, nível educacional e atividade profissional. Em 50% dos casos, os voluntários que adquiriram medicamentos em automedicação fizeram-no sob aconselhamento do farmacêutico. Os grupos terapêuticos mais utilizados em automedicação foram as preparações nasais e sistêmicas para a constipação e tosse (23,0%) e os analgésicos (13,6%). Analisando cada um dos grupos terapêuticos individualmente foram encontradas diferenças estatisticamente significativas relativamente ao perfil do utilizador por sexo e grupo etário, de acordo com a variável automedicação.

疑義照会支援システムの構築と運用−リスクマネジメントヘの活用−

Checking prescriptions is one of the most important tasks of the pharmacist. For this purpose, we have developed a computer database for answering pharmacist inquiries using Microsoft Access 97. This database allows us to search past records quickly and to check the details of inquiries that we made before. We used it to determine the frequency that prescriptions needed to be clarified by physicians. We also worked out the percentage of prescriptions that had been corrected after inquiries for each clinical department, and according to the nature of inquiries. It was found that pharmacists verified 0.26% of all prescriptions and that physicians changed 50.4% of these prescriptions based on the advice of pharmacists. Interestingly, prescription correction rates varied greatly among clinical departments. We also noted that there were some mistakes that arose as result of our current order-entry system. In conclusion, we consider our pharmacist inquiry database to be a useful tool for risk management in the clinical setting and that it will help us to reduce medication errors.

Patient satisfaction with skill mix in primary care: a review of the literature

This literature review focuses on patient satisfaction with skill mix in primary care. This is an important, rapidly changing, topic as the range of health professionals working alongside GPs increases and the roles of staff change. The review is intended to assist primary care organizations in developing skill mixes that meet patients' preferences and needs.A number of characteristics that influence the type of services that patients want were discovered. Older people and those from ethnic minorities want a ‘traditional’, GP-led service. Access is important to younger people and those in full-time work. Those from lower socio-economic groups value nurses, but have found the increasingly complex organization of services a problem. There are different levels of knowledge and expectations about health services and information on the skills and knowledge of professionals, what they do and the links between them, needs to be available.A number of aspects of care are important to patients. Patients liked nurses as they were good communicators, formed good therapeutic relationships, gave information on illnesses and spent more time. The location of services is important and patients liked services provided in the home or community. Continuity of care is key, but has been presented as old fashioned and reorganizations may have reduced continuity; skill mix could be viewed as forming a barrier between doctor and patient, but personal lists and teams where practices are divided into smaller units with shared support may help. The competence of health professionals is clearly vital and patients considered nurses competent, although they had concerns about nurses and pharmacists taking on some new roles.The literature focuses on patients' views about doctors and nurses, although they also want a wider range of services and professionals available in primary care: occupational therapy, link workers, CAB advisers, pharmacist advice and mental health workers. Despite being satisfied with nurses, some patients still wanted to see a doctor next time or felt that a doctor should be available. GPs can help build awareness and confidence in patients about the roles and contribution of the team.

Dose individualization in PharmDIS-e+.

Individualized dosage regimen calculations require knowledge on the pharmacokinetic and pharmacodynamic properties of the drug and the characteristics of the patient. A PK-PD-based dosage regimen is not easily and generally applicable, mainly because the combination of available PK parameters and therapeutic target levels may be inappropriate for the purpose of predicting a plausible dosage regimen. Within the project PharmDIS-e+, an alternative approach was chosen, and this "PK and standard dose"-based principle is well suited for computerized dosing advice. PharmDIS-e+ aims at the development of several applications for dosing regimen advice for general practitioners, hospital physicians and pharmacists.

Survey of Women's Attitudes to Complementary Medicines

Aim: To assess the attitudes of women to complementary medicines.Method: A questionnaire covering demographic information and 30 questions related to complementary medicines was developed. The questionnaire was distributed to women resident in Wollongong, NSW, Australia by mail (n = 785), with a further 793 distributed to complementary and conventional healthcare practices within the same postal zones.Results: The overall response rate was 31%. Respondents indicated that they are open to new alternatives in health (92% ), that the potential of alternative medicines is largely undiscovered (65%), that complementary medicines are more than placebos (81%) and that they can be used in conjunction with conventional medicines (79% ). Respondents also recognised the potential for interactions between complementary medicine and conventional drugs (66%). Eighty per cent disagreed with the statement that complementary medicines had nothing to offer them. Those visiting complementary practitioners viewed complementary medicines more favourably than those using conventional medical practices.Conclusion: This study has shown that women are generally open to complementary medicines and see them as a valuable addition to conventional health care. We have also shown that women recognise the potential limits of these medicines and trust the advice of pharmacists. This highlights the need for pharmacists and other healthcare professionals to be knowledgeable and non‐judgmental when providing advice about complementary medicines.

Public knowledge, attitudes and behaviour regarding antibiotics

Objective: To assess public knowledge, attitudes and behaviour regarding antibiotics to provide information for a local health education policy.Design: Postal survey to 605 patients registered with two general medical practices in Grampian, NorthEast Scotland (351 respondents, 59.3%) in February/ March 2000. Questionnaire topics covered attitudes, knowledge and behaviour towards antibiotic use.Results: 326 (93%) bad experience of antibiotic use and 319 (81%) were happy to take antibiotics when necessary. 158 (45%) were concerned about antibiotic resistance. Few would expect antibiotics to treat a slight cold or heavy cold, but around half would expect antibiotics for very sore throats and influenza. 262 (75%) indicated they would ask a pharmacist for advice about the treatment of RTI. Most respondents experienced at least one episode of RTI during the review period. 280 (80%) provided details of their most recent episode; most self-treated, 57 consulted a doctor of whom 43 (75%) were prescribed antibiotics.Conclusions: Antibiotic resistance is a matter of concern for the public. Mixed opinions about the use of antibiotics for common respiratory tract infection were heard. Encouragingly the majority of people suffering an RTI during the review period treated themselves with paracetamol-based products for symptom relief. Those who consulted a doctor were in the minority but were likely to be prescribed antibiotics. Future local health education initiatives should target antibiotic use for sore throats as well as colds and flu.

Using Health Observances to Promote Wellness in Community Pharmacies

To provide pharmacists in community practice a framework for using national health observances as opportunities to promote patients' health through education and screenings, to discuss obstacles pharmacists may encounter when developing services within their pharmacies, and to outline examples of activities pharmacists can perform for specific health observances. Articles published between January 1970 and April 2002 were identified through MEDLINE using the search terms wellness, disease prevention, health promotion, Healthy People 2010, treatment of high cholesterol, treatment of high blood pressure, and levels of participation. Additional articles were identified from Web sites and reports from the federal Office of Disease Prevention and Health Promotion (ODPHP), American Heart Association, American Diabetes Association, National Osteoporosis Foundation, National Cancer Institute, American Cancer Society, National Heart, Lung, and Blood Institute, Consumer Product Safety Commission, and Centers for Disease Control and Prevention. Healthy People 2010 is a federal program with the goal of increasing the quality and years of healthy life and eliminating health disparities among populations. ODPHP publishes a list of national health observances each year. Community pharmacists can use these month- and week-long observances as opportunities to work toward achieving Healthy People 2010 goals by advocating, facilitating, and/or providing education and screenings to their patients. This article presents advice for pharmacists who want to develop pharmacy-based health promotion activities at various levels of resources and commitment. Specific suggestions include tips on preparing for and implementing education and screening programs and overcoming potential obstacles. As the most accessible health care professionals, pharmacists are in a unique position to help the nation achieve the goals of Healthy People 2010 through their involvement in the promotion of wellness.

Can Applied Entrepreneurship Education Enhance Job Satisfaction and Financial Performance? An Empirical Investigation in the Australian Pharmacy profession

This research investigated a small-scale example of an applied entrepreneurship education program, the Pharmacist Advice Program. 25 New South Wales pharmacists who had undertaken the program were compared to 23 who had not. Non parametric statistical techniques were employed to test the related propositions that pharmacists who learned and applied the entrepreneurship taught in the program (program ‘users’) would experience increased job satisfaction and better sales/profit performance than ‘non-users’. Results support the proposition that entrepreneurship education enhanced job satisfaction. The quantitative analysis on sales/profit performance data was less conclusive but a majority of users believed the applied entrepreneurial learning of the Pharmacist Advice Program led to improvement. The study makes a positive contribution to substantive knowledge in the pharmacy industry and formal theoretical investigation of the field of entrepreneurship education. CAN APPLIED ENTREPRENEURSHIP EDUCATION ENHANCE JOB SATISFACTION AND FINANCIAL PERFORMANCE? AN EMPIRICAL INVESTIGATION WITHIN THE AUSTRALIAN PHARMACY PROFESSION. Pharmacy, is a ‘dual market’ industry. A pharmacist must combine retailing with provision of professional services. On the retail side, there is growing competition from non pharmacy retailers with many manufacturers selling their goods through non pharmacy outlets. On the other side of the business, successive Australian governments have gradually reduced prescription margins available to the pharmacy from the National Health Scheme. Moves towards increasing industry deregulation may soon allow ownership of pharmacies by non pharmacists such as supermarkets, chain stores and other retailers. To avoid this, the retail pharmacy industry needs to demonstrate a community benefit of the existing pharmacist-only ownership restrictions by changing their focus to a more professional and patient orientated approach, whilst simultaneously improving business skills. So, many pharmacists are belatedly recognising the need to better blend the retail and professional services sides of their businesses by seeking to become more entrepreneurial. But, until the advent of the Pharmacist Advice Program, most had not had any structured education in entrepreneurship. This set of circumstances provided the opportunity for empirical investigation of some propositions at the heart of the developing field of entrepreneurial pedagogy.

The cost effectiveness of a pharmacist reviewing medication among the elderly in the community

Aims : The study aims to assess the cost effectiveness of medication review and advice by a consultant pharmacist to elderly people living in the community in Australia. Method : The quality of life and cost of health and social services for a cohort of elderly patients seen by an aged care assessment team (ACAT) was measured at initial referral and at one month follow up. Sites in Melbourne and Ballarat were chosen and analysed separately. A second subsequent cohort was assessed by a team, which included a pharmacist who provided advice to the team and the patient's GP. Quality of life was measured using the SF‐36 and the AQoL. Results: Patients seen by an ACAT had a quality of life considerably below full health. Overall there was no significant change in quality of life in either group by either measure. The additional cost of the pharmacist was less than 77 per patient. Compared to no intervention, there was some evidence of an increase in the cost of prescription Pharmaceuticals, and a reduction in home care assistance and medical care costs in Melbourne but not in Ballarat. Cost data were highly skewed however, making statistical tests of cost differences problematic. The addition of a pharmacist may be cost reducing in some settings especially if inpatient episodes for assessment and treatment can be avoided, but the study was not able to demonstrate a statistically significant reduction in overall costs associated with pharmacist review and advice.

The Dietary Supplement Dilemma: Practice Advice for Pharmacists

The Dietary Supplement Dilemma: Practice Advice for Pharmacists

Evaluation of the impact of pharmacist's advice giving on the outcomes of self-medication in patients suffering from dyspepsia.

The aim of this study was to investigate the outcomes of self-medication in patients suffering from dyspepsia by comparing changes in the Health related Quality of Life before and after self-medication of dyspeptic disorders. Another study objective was the quantitative and qualitative analysis of the pharmacist's advice-giving to patients with dyspepsia. Therefore the impact of the counselling by the pharmacist on the patient's health outcomes was surveyed and compared between study and control pharmacies. Moreover, the study analysed the influence of a special training on the services provided by the pharmacies with regard to self-medication. A beneficial effect of self-medication on the HRQoL of patients with dyspepsia on a weekly basis has been detected in the study. There is evidence that advice-giving and counselling by the pharmacists in self-medication have a measurable impact on self-medication outcomes. Moreover, the study reveals that patients value the information provided by the pharmacist. Pharmacists gathered the relevant and comprehensive information from the patients having dyspeptic symptoms and provided advice concerning OTC-drugs. Moreover, pharmacists frequently discussed the relevance of factors aggravating dyspeptic disorders such as lifestyle, drinking, smoking, and manner of nutrition with the patient. Training programs and treatment guidelines for the pharmacist seem to obtain a positive effect on his performance. The findings of the study substantiate the value of a pharmacist-controlled self-medication. The study results suggest that the quality of primary health care in self-medication would improve if pharmacists' involvement were even more intense.

Drug utilization and health behaviours among indigent elderly patients in Crete, Greece.

To examine pharmaceutical needs, prescribed drugs, knowledge about pharmacotherapy and health behaviours among Social Care indigent elderly patients. There were a total of 551 Social Care indigent patients registers in Chania, Crete, Greece at the time of the study (1995-97), of whom 89 (40 men and 49 women) were elderly patients (> or =65 years old). The control group comprised 171 (81 men and 90 women) Social Security insured elderly patients (> or =65 years old). The socio-demographic profile of the indigent elderly patients reveals an unemployment rate of 99% (versus 5% in the control group, P<0.05) and an illiteracy rate of 38% (versus 5%, P<0.05). The most commonly prescribed defined daily doses (DDD) of medications were cardiovascular drugs (45.0% indigent versus 48.3%) and nervous system drugs (14.4% versus 8.8%). The most frequently prescribed drug, as a percentage of DDD, was nitroglycerin (14.5% versus 26.0%) and the most expensive drug, expressed as a percentage of the total cost of drugs, was omeprazole (6.5% versus 4.6%). The most common disease was hypertension (42.1% versus 23.2%, P<0.05). There were also significant differences between the two groups of patients (P<0.05) in the understanding of drug usage instructions (35.4% versus 68.6%), in asking the pharmacist for advice (44.6% versus 71.5%) and in understanding special diet instructions (18.7% versus 34.7%). Regarding the health behavior patterns, significant differences (P<0.05) were found in the consumption of sausages (38.6% versus 15.6%), salt (29.8% versus 12.0%), more than one glass per day of alcoholic drinks (13.8% versus 4.3%) and in daily smoking cigarettes (48.8% indigent versus 12.8% control). The present study emphasizes the need for more information on drug use and the necessity for a continuing health educational intervention among Social Care indigent elderly patients.

Societal perceptions of community pharmaceutical services in Malta.

To assess the views of the Maltese general public on services provided by community pharmacies in Malta and their opinions on the proposed extended role for pharmacies. An interviewer-administered structured questionnaire was used to interview 912 members of the public (395 males, 517 females). The majority of respondents (70.8%) visited a pharmacy at least once a month, with females visiting more frequently than males (P< 0.01). Almost 31% stated that the main reason for visiting a pharmacy was to purchase prescribed medication, while 23-3% said that it was to obtain over-the-counter products. Women were more likely than men to be influenced by the pharmacist's advice when selecting an over-the-counter product (P< 0.05). The majority of respondents (62.8%) said that they usually bought their medicines from the same pharmacy and loyalty to a particular pharmacy increased with age. When treating minor ailments, respondents were more likely to consult their doctor or self-treat rather than seek advice from the pharmacist. The proposed extended role of the community pharmacist found support with the public, e.g. 90.2% felt that the pharmacist should promote health education, with the preferred method suggested being through individual advice; 85-7% were in favour of screening and monitoring services and 85.6% felt that the keeping of patient medication records would be useful. Almost three-quarters (74.6%) of respondents said that they would be willing to participate in pharmaceutical care programmes. When asked to suggest new activities for community pharmacy, respondents were most in favour of the pharmacist offering more advice on the treatment of minor ailments. Overall, the results obtained are encouraging and Maltese pharmacists should plan to provide new services to the community in the future.

Antibiotics prescription for indigent patients in primary care.

A drug use evaluation focusing on prescribed antibiotics among Greek indigent and Social Security patients. Four hundred and forty-six indigent patients insured by Social Care and 332 patients insured under Social Security Funds were interviewed and their prescription records reviewed. Although 88.5% of indigent patients stated that they had received instructions on antibiotic use and had understood these instructions, only 45.9% could correctly repeat these instructions. Only 9.9% read the enclosed leaflets and 59.4% reported asking the pharmacist for advice, 54.1% of these patients were unaware of the dosage of their medication, and the length of treatment was only written in 13% of cases. The most common diseases among indigent patients were respiratory infection (11.7%) and dental problems (10.1%). The latter ranked 11th among the insured patients (3.7%). Tuberculosis (3.3%) was still one of the most common diseases among the indigent patients. Overall, 30.9% of the prescribed daily defined dose (DDD) of medication for the indigent patients were for cardiovascular drugs (16.9% of the cost), 19.5% were for nervous system drugs (8.9% of the cost), 13.5% for gastrointestinal tract drugs (14.1% of the cost) and only 4.3% were antibiotics (but 16.9% of the cost). The most frequently prescribed antimicrobials were penicillins (45.6%), cephalosporins (19.7%), macrolides (12.6%) and quinolones (9.6%). Antituberculous agents made up 13.7% of the antibiotic prescriptions. The most widely prescribed antibiotics were amoxycillin + clavulanate (19.3%), amoxycillin (7.9%), cefaclor (5.6%), clarythromycin (5.1%) and rifampicin + isoniazid (6.3%). The present study emphasizes the need for more information on drug use among indigent patients and their information needs.

複数科受診患者の重複・相互作用処方に関する検討

A support system for prescriptions was added to the Gifu University Hospital prescription ordering system in July 1994. The information on other prescriptions for patientswho were consulting multiple clinical departments in our hospital was printed on the prescription sheet to support the dispensing process. These prescriptions are indicated on a computer display using the printed information (e.g., department and prescription date). Drug duplications and drug interactions including the medications which were prescribed by other department are subsequently checked by pharmacists.The rate of prescriptions on drug duplications decreased significantly from 14.0% in June to 2.6% in October (p<0.05) since the support system was introduced. The rate of prescriptions generating drug interactions did not significantly decrease. However, some doctors modified the medication order or carefully maintained the medication order to prevent the occurrence of undesirable drug interactions as a result of the pharmacist's advice. These findings suggest that this support system is useful for preventing overdosing and adverse reactions that may be induced by drug duplications or drug interactions