What is a potential risk of long-term use of high doses of beta-agonists?

Long-term use of high doses of beta-agonists can lead to the development of tolerance, meaning that over time, the body becomes less responsive to the medication. As a result, patients may find that they require higher doses to achieve the same bronchodilator effect, which can be problematic, particularly for those with chronic respiratory conditions such as asthma or chronic obstructive pulmonary disease (COPD). This tolerance development can make it challenging to manage symptoms effectively, leading to potential exacerbations or worsening of the condition.

In contrast to the other options, developing an increase in lung capacity does not align with the risks associated with beta-agonist use. Immediate respiratory failure is an acute event and not a common outcome of prolonged beta-agonist therapy. Excessive mucus production is also not directly tied to beta-agonist use; rather, it is more often associated with other underlying respiratory issues. Thus, the correct answer focuses on tolerance, which highlights an important aspect of managing treatment in patients requiring long-term bronchodilation.