Report of the UK Cystic Fibrosis Trust Antibiotic Working Group

5.14 Antibiotic delivery5.14.1 Antibiotic preparationsColistin is dispensed as a dry powder preparation and reconstituted as a solution using 0.9% sodiumchloride, Water for Injections or a 50:50 mixture to a volume of 4 ml for continuous nebulisation.(2.5 ml for a low residual volume nebuliser). Chest tightness is a known side effect of the drug andthis may be minimised by altering the tonicity of the solution. 70 The I-neb ® requires a volume of 1ml and should be used with the Promixin ® brand of colistin.Reconstituting colistin with a bronchodilator is an emerging practice to shorten treatment times. 66 Itis recommended that admixtures should be prepared immediately before use, with preservative freediluents and both the physico-chemical compatibility and aerodynamic properties of the mixturesshould be considered. 71;725.14.2 Recommendations for reconstitution of nebulised antimicrobials• Colistin should be reconstituted to an isotonic or hypotonic solution [D].• To prepare an isotonic solution of Colomycin® suitable for nebulisation in adults: 2MU in 4.0ml -> add 2.0 ml water for injections + 2 ml of 0.9% sodium chloride [D].• To prepare an isotonic solution of Colomycin® suitable for nebulisation in children: 1MU + 1ml water for injections + 1 ml 0.9% sodium chloride. (For children over 10 years the 2MU dosemay be more suitable – see section 5.15 below) [D].• TSI is dispensed as a ready to use solution in a 300 mg/5 ml vial [D].• Colistin should be reconstituted immediately before use [D].• A supervised test dose should be performed with measurement of spirometry before and afterinhalation [D].• Any induced bronchoconstriction may be prevented by preceding the inhalation with abronchodilator [D].5.15 Antibiotic dosesThere is no evidence base for the dose of colistin. The licensed doses are as follows:Children 2 years and adults: 1–2 million units bdMany CF centres use 1MU bd for children