Inhaled Corticosteroid Therapy in Adult Asthma Time for a New Therapeutic Dose Terminology

The Global Initiative for Asthma guidelines use the traditional terminology of "low," "medium," and "high" doses of inhaled corticosteroids (ICS) to define daily maintenance doses of 100 to 250 mu g, >250 to 500 mu g, and >500 mu g, respectively, of fluticasone propionate or equivalent for adults with asthma. This concise clinical review proposes that this terminology is not evidence based and that prescribing practice based on this terminology may lead to the use of inappropriately excessive doses of ICS. Specifically, the ICS dose that achieves 80-90% of the maximum obtainable benefit is currently classified as a low dose, with the description of two higher dose levels of medium and high, which are associated with significant risk of systemic adverse effects. Asthma guidelines and clinician prescribing practice need to be modified in accordance with the currently available evidence of the dose-response relationship of ICS in adult asthma. We propose a reclassification of ICS doses based on a "standard daily dose," which is defined as 200-250 mg of fluticasone propionate or equivalent, representing the dose at which approximately 80-90% of the maximum achievable therapeutic benefit of ICS is obtained in adult asthma across the spectrum of severity. It is recommended that ICS treatment be started at these standard doses, which then represent the doses at which maintenance ICS are prescribed at step 2 and within ICS/long-acting beta-agonist combination therapy at step 3. The opportunity is available to prescribe higher doses within ICS/longacting beta-agonist maintenance therapy in accordance with the stepwise approach to asthma treatment at step 4.