The need for inhaled phosphodiesterase inhibitors in chronic obstructive pulmonary disease

Introduction The therapeutic implications of phosphodiesterase (PDE) inhibitors have attracted interest because PDEs are regarded as an intracellular target to be exploited for therapeutic advancements in the treatment of COPD. At present, the only approved approach for the treatment of COPD with PDE inhibitors is the use of an oral PDE4 inhibitor. However, this treatment is not widely employed, primarily due to the narrow therapeutic index associated with oral PDE4 inhibitors, which considerably restricts the permissible dosage. The inhalation route represents a viable alternative to the oral route for improving the therapeutic index of PDE4 inhibitors.