Medicaid formularies: a critical review of the literature.

Studies on the impact of restricted Medicaid formularies were reviewed to assess whether other drugs on the formulary were substituted for restricted drugs, the cost of the substitutes, whether the substitutes were therapeutically appropriate, whether restricted drugs continued to be prescribed, what incremental administrative costs accompanied restrictions, what indirect costs occurred and how the cost-effectiveness of pharmaceuticals impinged on the total cost of illness. The assumption that restriction of specific drugs results in savings in the drug costs proportional to prior usage was shown to be questionable, numerous studies found alternate formulary drugs to the restricted drugs being prescribed, or patients were paying out-of-pocket for denied drugs. There was a tendency for alternate drugs to be more expensive. Little information exists as to the incremental administrative costs of restricted formularies or the therapeutic appropriateness of substituted drugs. One study suggests that major shifts in costs occur due to restrictive formularies through substitution of more expensive services such as hospitalization in lieu of pharmaceuticals. It is concluded that restricting formularies leads to dynamic changes in the total Medicaid program of a complex and often costly nature. Plans to implement formulary restrictions require considerable careful thought.     

Rule-based standardised switching of drugs at the interface between primary and tertiary care

Introduction Changes in drug treatment are frequently mandatory with hospital admission and discharge because hospital drug formularies are generally restricted to about 3000 drugs as compared to the many times this number – 62,000 in Germany – that are commercially available. Without computerised support, the process involved with switching drugs to a corresponding generic or a therapeutic equivalent is time-consuming and error-prone. Methods We have developed and tested a standardised interchange algorithm for subsequent implementation into a computerised decision support system that switches drugs to the corresponding generic or a therapeutic equivalent if they are not listed on the hospital drug formulary. Results The algorithm was retrospectively applied to the medication regimens of 120 patients (774 prescribed drugs containing 886 active ingredients) at their time of admission to surgical wards. Of the prescribed drugs, 52.8% (409/774) were part of the hospital drug formulary, thereby rendering a switch unnecessary. The 365 drugs not listed consisted of 392 active ingredients that were successfully switched to a corresponding generic (84.7%) or a therapeutic equivalent (10.2%). No specific switching procedures were defined for only 2.3% (20/886) of the active ingredients. In these cases, the drugs were either discontinued (4/20) or special drug classes, current diseases or co-medication required manual switching (8/20), or the drugs were continued unchanged and ordered from a wholesaler (8/20). Conclusion Using a standardised interchange algorithm, pre-admission drug regimens can successfully be switched to drugs on a hospital drug formulary. These findings suggest that a computerised decision support system will likely be useful to support this important practice.     

Narrow and wide prescribers among general practitioners

Objective The aims of this study were to analyse (1) if it is possible to classify general practitioners (GPs) or groups of practitioners (practice units) as overall narrow or wide prescribers and (2) to what extent the size of practice drug formularies is associated with general prescribing behaviour, practice activity and demography.Methods Data were retrieved from the Odense University Pharmacoepidemiologic Database (OPED) and the prescribing patterns of 177 practice units were analysed in a 4-year period including 2000 and 2003. We characterised the drug repertoire for new treatments using a Formulary Diversity Scale based on two formulary measures, the DU 90% and the Formulary Selectivity Index. Multiple regressions were used to analyse the association between formulary size and practice characteristics.Results The final Formulary Diversity Scale comprised 15 therapeutic drug groups and 151 different analogues. The average score based on the DU 90% segment was 46 drugs (range: 28–65) corresponding to 30% of drugs available. Using the Formulary Selectivity Index the average diversity score was 0.70. Practices with a high number of patients and a high percentage of elderly patients were more likely to use a wide range of drugs.Conclusion The Formulary Diversity Scale revealed wide variation between practice units, indicating the existence of both overall narrow and wide prescribers among GPs. The number of patients attending the practice and the percentage of elderly patients were directly associated with the use of more analogues.     

Influences on prescribing: the perceptions of general practitioners in two primary care trusts

We describe results from a postal questionnaire sent to all GPs (general practitioners) in two East London primary care trusts investigating perceived influences of prescribing and their attitudes towards the local formulary The strongest influencing factors on prescribing are: “the drug is recommended by a specialist or peer”, “guidelines”‘ and “GP's own previous experience of the drug” The weakest influencing factors are: “visits from drug representatives”, “advertisements in journals and magazines” and “internet information” GPs need, agree and comply with local formularies but they do not use them much; still, GPs are influenced by local formularies but the influence of pharmaceutical advisers remains uncertain The more we know about what influences prescribing, the better we can design steering interventions so that drugs are being prescribed wisely and cost effectively     

Evaluating a restrictive formulary system by assessing nonformulary-drug requests

Nonformulary-drug requests were used to evaluate a restrictive formulary system in a large university hospital, and a telephone survey of eight similar hospitals was conducted to assess the restrictiveness of their formulary systems. Nonformulary-drug requests were evaluated by two drug information pharmacists over a 12-month period (January-December 1984) to assess the frequency with which nonformulary items were ordered, the costs associated with the procurement of nonformulary drug products, and the rationales given by physicians when ordering nonformulary products. Of all nonformulary requests, 65% were for drugs previously evaluated by the pharmacy and therapeutics committee and denied admission to the formulary. A cost savings of $1887 would have resulted if formulary alternates had been used instead of nonformulary products. Excluding 22% of nonformulary items that were requested for the continuation of preadmission drug therapy, only 13% of the rationales for the remaining requests were appropriate. Although the eight other hospitals surveyed said they had restrictive formularies, all had frequent requests and procedures for procuring nonformulary items and some formularies included most available drugs. The formulary system at the study hospital was considered restrictive, but procedures for nonformulary-drug requests limited the effectiveness of the system. If any benefit is to result from formulary systems, hospitals must strengthen their enforcement of formulary restrictions.     

Superior hospital formularies: a critical analysis

The drug monograph section of eight superior hospital formularies was examined to (1) determine the type of pharmaceuticals, including dosage forms, listed, (2) delineate patterns of concurrence and divergence in drug acceptance, and (3) ascertain quantitative benchmarks by therapeutic category that may suggest optimum formulary size. The survey also undertook a comparative analysis of marginal drugs and reviewed the role of pharmacy personnel in supporting formulary administration. The critique of pharmaceutical preparations revealed significant patterns of similarity, heterogeneity, perplexity, and redundancy. The investigation also documented problems in dosage form selection and formulary publication. The report concludes that there is a need for more comprehensive studies that incorporate alternative quality assurance methods and focus on the more intangible factors of professional leadership and integrity.     

Experience with a two-tiered therapeutic interchange policy

A university hospital's formulary policy for therapeutic interchange is described in which pharmacists can routinely interchange some drugs but must contact the prescribers before interchanging other drugs. For drugs that are not automatically interchanged by the pharmacy, the formulary contains a "class representative," which pharmacy may change as relative prices of drug products change. When a non-formulary drug for which there is a designated class representative is prescribed, pharmacy contacts the prescriber. When a class representative for injectable histamine H2-receptor antagonists was being selected, previous positive and negative experiences with establishing therapeutic equivalence for antimicrobial agents were considered. The implementation of H2 antagonist therapeutic equivalence included the following steps: determining potential cost savings, reviewing the literature, consulting with specialty practitioners, presenting the information to the pharmacy and therapeutics committee, distributing formal bids, and educating hospital staff. Before cimetidine was designated the class representative, 84% of orders for injectable H2 antagonists were for ranitidine; one year later, 90% were for cimetidine. Orders for oral H2 antagonists also changed from predominantly ranitidine to predominantly cimetidine. The hospital's total costs for H2 antagonists decreased 8.4% in one year. The two-tiered approach to therapeutic interchange can reduce drug costs and increase the scope of agents deemed therapeutic equivalents in a manner that is acceptable to physicians and pharmacists.