Due to their fast onset of action, they have been selected as first-line therapy for quick relief in persistent and intermittent asthma and bronchospasm.[2] Patients may experience dizziness, heart palpitations, hyperglycemia, diarrhea and muscle cramps when taking these medications. Importantly, medications that antagonize the β2 receptor (β-blockers) may significantly increase the risk of asthma exacerbations, and are generally avoided in asthmatic patients.[3] Corticosteroids: Inhaled corticosteroids (e.g. fluticasone, budesonide) are typically used when bronchoconstrictive disease has advanced to a persistent inflammatory state, more specifically in persistent or severe asthma and chronic obstructive pulmonary disease (COPD).[citation needed] These medications decrease immune system activity which in turn will decrease swelling of the airways, decrease airway resistance, and increase delivery of air to the alveoli during respiration. Unlike the SABAs, these medications do not provide relief of acute symptoms or asthmatic attacks, and their benefits are typically only seen after 3–4 weeks of therapy.