Aclidinium bromide (INN) is a long-acting, inhaled muscarinic antagonist (LAMA) approved in the United States in July 2012[3] as a maintenance treatment for chronic obstructive pulmonary disease (COPD).

[4] Evidence shows that it can improve quality of life and prevent hospitalization in those with COPD.

Common side effects (in more than 1% of patients) are sinusitis, nasopharyngitis, headache, cough, diarrhoea and nausea.

Skin reactions such as rash, as well as side effects that are typical of muscarinic antagonists (fast heart rate, palpitations, and urinary retention), occur in less than 1% of patients.

It is expected that adverse effects of aclidinium increase if it is combined with other muscarinic antagonists.

The substance is quickly hydrolysed to the carboxylic acid and the alcohol, so that less than 5% of the inhaled dose are found unchanged in the plasma.