was calculated. Considering a switch to aztreonam lysine, the reduction of exacerbation was estimated in order to maintain the overall treatment cost. For the base case, ex-factory prices were considered; for sensitivity analysis, discounts ranged from 15 to 50%. Results: Switching to aztreonam lysine would not increase overall treatment costs in 8/12 options; even maintaining current exacerbation episodes could lead to SNS savings. In the remaining options, the required reduction of exacerbations varies depending on the patient's current situation, ranging from 110% (one episode/ year) to 18% (six episodes/year). In the sensitivity analysis, there are 3 options in which switching to aztreonam lysine would not imply higher treatment costs. For the remaining alternatives, the required reduction of exacerbations does not change significantly from the base case: from 116% (one episode/year) to 19% (six episodes/ year). ConClusions: In CF patients with chronic pulmonary infection by PA, hospitalizations costs due to exacerbations have a greater economic impact than drug treatment costs. Using aztreonam lysine, instead of other treatments, would not imply a budget impact in a wide range of patient profiles if exacerbation episodes can be reduced. As the number of current exacerbations increases, a lesser reduction of these events is required by a switch to aztreonam lysine to avoid incremental treatment costs.objeCtives: Meprobamate is a constituent of various combination analgesics in South Africa. Due to its abuse potential, the scheduling status of meprobamate is currently under review with the possibility of introducing stricter controls on its availability. The primary aim was to determine the impact of generic substitution on meprobamate-containing combination analgesic prescribing. Methods: A retrospective, cross-sectional drug utilisation study was conducted on prescription data of a medical insurance scheme administrator in South Africa for 2011. Results: A total of 97 491 analgesics were dispensed to 31 854 patients during the year. Within ATC category N02B, 62.10% of prescriptions were for analgesic combinations, of which 20 326 prescriptions were for meprobamate-containing analgesics at a cost of R282 930. A total of 10 404 patients received meprobamate-containing analgesics. Overall, 20.85% of all analgesics contained meprobamate. Patients who received meprobamate-containing analgesics were slightly older (39.52 years) compared to patients who received analgesics in general (33.61 years). Mandatory generic substitution exists in South Africa, unless otherwise indicated by the prescriber or if the patient refuses. Twenty-two trade names of meprobamate-containing analgesics were dispensed, of which 17 (the originator plus 16 branded generics) contained exactly the same dosages of active ingredients (320 mg paracetamol, 8 mg codeine phosphate, 32 mg caffeine and 150 mg meprobamate). In previous studies, the originator product was the most often prescribed, yet in this study the originator product only consti...