Fragmented markets for older antibiotics and child formulations, Denmark, Norway, Sweden.

Antibiotic resistance is one of the most urgent threats to public health. The development of antibiotic resistance can be reduced by the use of narrow-spectrum antibiotics that target specific bacteria, meaning that fewer non-harmful bacteria are killed and other harmful bacteria are not exposed to selection pressure. However, many narrow-spectrum antibiotics were introduced decades ago and therefore lack regulatory documentation in line with current standards. An additional problem for a reliable supply is that of market fragmentation, where countries with similar resistance patterns and prescribing cultures (e.g. Norway and Sweden) prioritize different formulations and strengths. For example, over half of Sweden's highest priority paediatric antibiotics are not marketed in Denmark or Norway in the same formulations or dosages. Such market fragmentation, which can result in the annual demand of a country being smaller than batch production sizes, means that specific strengths and formulations may no longer be economical to supply. Further, once an antibiotic has been withdrawn from the market, it is difficult to attract a new supplier because of the cost of the clinical trials required to update approval of the drug. However, as resistance to antibiotics increases among populations, clinicians need access to the maximum possible range of antibiotics. Regional collaboration, that is, the harmonization of essential medicines lists (including strengths and formulations for older antibiotics) between countries, is a recommended first step towards reliable access to the necessary range of antibiotics.