The evidence indicates that there are few consistent significant differences in effects between the five ICS licensed for use in adults and adolescents over the age of 12 years, at either low or high dose. On average, BDP products currently tend to be the cheapest ICS available and tend to remain so as the daily ICS dose required increases. There is evidence that the addition of a LABA to an ICS is potentially more clinically effective than doubling the dose of ICS alone, although consistent significant differences between the two treatment strategies are not observed for all outcome measures. The cost differences between combination therapy compared with ICS monotherapy are highly variable and dependent on the dose required and the particular preparations used. For the combination therapies of ICS/LABA there are potential cost savings with the use of combination inhalers compared with separate inhalers, with few differences between the two treatment strategies in terms of effects. The only exception to this cost saving is with BUD/FF at doses higher than 1200 microg/day, where separate inhaler devices can become equivalent to or cheaper than combination inhalers. Neither of the two combination inhalers (FP/SAL or BUD/FF) is consistently superior in terms of treatment effect. A comparison of the costs associated with each combination therapy indicates that at low dose FP/SAL delivered via a pMDI is currently the cheapest combination inhaler but only marginally cheaper than BUD/FF delivered as a DPI. At higher doses, both the FP/SAL combination inhalers (PMDI and DPI) are marginally cheaper than BUD/FF (DPI). Future trials of treatment for chronic asthma should standardise the way in which outcome measures are defined and measured, with a greater focus on patient-centred outcomes. For informing future cost-utility and cost-effectiveness analyses from a UK NHS perspective, there is a need for longitudinal studies that comprehensively track the care pathways followed when people experience asthma exacerbations of different severity. Further research synthesis, quantifying the adverse effects of the different ICS, is required for treatment choices by patients and clinicians to be fully informed.
Long term use of topical corticosteroids can induce tachyphylaxis (tolerance to the vasoconstrictive action of topical corticosteroids). Adverse effects are uncommon when using mild to potent corticosteroids for less than three months, except when used on the face and neck, in intertriginous areas (skin folds), or under occlusion. However, very potent corticosteroids should not be used continuously for longer than three weeks. 2 If longer use of very potent corticosteroids is required, they should be gradually tapered to avoid rebound symptoms and then stopped for a period of at least one week after which treatment can be resumed. 2