There are many possible functions of a DTC, and the committee must decide which to undertake as a priority; this decision may depend on local capacities and structure. Furthermore, certain functions will require liaison with other committees or teams, for example the infection control committee or the procurement team. The most important DTC functions are summarized below.

1.3.1 Advisory committee to medical staff, administration and pharmacy

The DTC is a valuable resource that can provide advice to medical staff, nurses, administration, pharmacy and other departments and groups within the hospital. The DTC can advise on all issues, policies and guidelines concerning the selection, distribution and use of medicines. Usually a DTC will provide advice and an executive body, usually the pharmacy or hospital management, will implement it.

1.3.2 Development of drug policies

The DTC is the most appropriate body to develop drug policies within a hospital or group of health facilities, since the committee members will have the most experience and training in drug therapy and supply. Policies and procedures are the primary activity within a DTC, since they provide the foundation for other recommendations that may later arise from the DTC. Drug policies may vary in different hospitals and countries, but all hospitals should have specific policies concerning:

• criteria for inclusion of medicines on the formulary list (essential medicines list (EML))

• standard treatment guidelines and treatment algorithms, which should be the basis of formulary selection

• periodic use of medicines not on the formulary list, for example restricting their use to specified prescribers on a named patient basis only, or only allowing 10% of the hospital medicines budget to be spent on them

• expensive or dangerous medicines, such as third-generation antibiotics or oncological drugs, which are restricted to certain practitioners, departments or patients (structured order forms may be used to implement this policy)

• drugs that are under investigation for safety or efficacy

• generic substitution and therapeutic interchange

• drug representatives and promotional literature.

1.3.3 Evaluating and selecting medicines for the formulary list

Perhaps the most important function of a DTC is the evaluation and selection of medicines for the essential medicines list or formulary list. Drugs should be selected on the basis of the standard treatment guidelines or protocols that have been developed or adapted for use in the hospital or health facilities. The evaluation of medicines requires significant expertise and time commitment and a rigorous, transparent approach. Documented evidence for the efficacy, safety, quality and cost of all drugs under consideration for inclusion in the formulary list must be examined. Periodic review is necessary because of changing costs and indications, new information on safety, and the emergence of new medicines. The documents reviewed will depend upon the expertise of the committee and may include reputable textbooks, published treatment guidelines and formularies, newsletters and primary drug literature. See section 3.2 and chapter 4 for more information on selection and evaluation of medicines.

1.3.4 Developing standard treatment guidelines

Standard treatment guidelines (STGs) or protocols are a proven way to promote rational use of medicines provided they are:

• developed in a participatory way involving end-users

• easy to read and up to date

• introduced with an official launch, training, supervision and wide dissemination (Grimshaw and Russell 1993, Woolf et al. 1999).

Furthermore, STGs provide a benchmark of optimum treatment in the monitoring and audit of drug use. A DTC should either develop STGs from scratch or adapt them from elsewhere for use in their own hospital. Development of STGs from scratch will result in greater local ownership and acceptance, but is difficult and will consume time and resources. Adaptation or adoption of STGs from elsewhere is much easier and quicker, but will result in less local ownership and acceptance. See section 3.4 for more information on treatment guidelines.

1.3.5 Assessing medicine use to identify problems

Appropriate changes within the formulary list or other interventions may correct a number of problems in how medicines are used. It is important for the DTC to identify the priority problems and make appropriate recommendations. Appropriate methods to identify drug use problems include:

• aggregate drug consumption data review including ABC and VEN analysis and use of defined daily dose (DDD) methodology (see section 6.1)

• monitoring indicators of medicine use, including adherence to standard treatment guidelines (see section 6.2)

• drug use evaluation (DUE), also known as drug utilization review (see section 6.4)

• monitoring adverse drug reactions and medication errors (see chapter 5)

• antimicrobial resistance surveillance (see section 8.1).

1.3.6 Conducting effective interventions to improve medicine use

There is no point in a DTC collecting information on drug use problems if nothing is done to correct the problems identified. The DTC is the main body within a hospital, or group of health facilities, responsible for ensuring that drug information is provided to health staff and also for conducting interventions to promote more rational drug use. Monitoring and supervision, audit and feedback, educational programmes, in-service training, use of standard treatment guidelines, provision of unbiased drug information, prescribing restrictions and automatic stop orders are some important interventions. See chapter 7 on strategies to promote the rational use of medicines.

1.3.7 Managing adverse drug reactions

Adverse drug reactions (ADRs) are serious in terms of patient harm (morbidity and mortality) and avoidable economic costs. One large meta-analysis estimated that ADRs cause 3-4% of all hospital admissions in the USA and that in 1994 the incidence of ADRs was 6.7% (2.2 million events) with 106 000 fatalities (Lazarou et al. 1998). These estimates should be viewed with caution because of the heterogeneity among studies and small biases in the sample, but the data nevertheless suggest that ADRs are a large and serious problem. Adverse drug reactions may be due to the unknown effects of new (or older) drugs, unknown drug combinations and interactions, or poor drug quality. DTCs are responsible for ensuring that patients are treated as safely as possible. Monitoring and minimizing adverse drug reactions is an essential part of this function (see section 5.3).

1.3.8 Managing medication errors

Medication errors occur in all health-care settings, no matter how good the health-care staff are at prescribing, dispensing and administering medicines. Even if there is no error on the part of health-care staff, patients may take drugs incorrectly. Causes are numerous and include lack of knowledge, tiredness of staff, careless work attitudes, poor procedures, lack of policies, unfamiliar dosage forms and human error. DTCs can reduce such errors by monitoring, analysing, reporting errors and implementing corrective action (see section 5.1).

1.3.9 Information dissemination and transparency

The DTC must disseminate information about its activities, decisions and recommendations to the staff who must implement the DTC’s decisions. This may seem obvious, but it is often forgotten. Inadequate dissemination of information leads to a loss of credibility. It is also very important that the DTC operates in such a way as to ensure transparency of all its decisions and to avoid conflict of interest. In particular, members should either have no relationship with pharmaceutical companies or declare it openly so that conflicts of interest can be avoided. The only acceptable contact with pharmaceutical companies is to ensure the flow of information about their drug products in a way that is as unbiased as possible (see sections 2.1 and 7.4.2).