Seretide Diskus is a prescription inhalation medication containing salmeterol and fluticasone propionate. Each dose delivers 50mcg of salmeterol and 250mcg of fluticasone propionate. The inhaler contains 60 pre-measured doses for the treatment of asthma and COPD symptoms. This is a prescription medication manufactured by GlaxoSmithKline (GSK). The powder formulation also contains lactose as an inactive ingredient. The Diskus device is a dry powder inhaler that delivers precise doses of medication. A prescription from a licensed healthcare provider is required for this medication.