Briefly describe the pharmacology of medications available to treat asthma.

Briefly describe the pharmacology of medications available to treat asthma. Which medications are used for long-term control, and which ones for acute attacks? Outline a treatment plan based on the degree of severity.

The medications used to treat asthma are detailed in Table 80.3.

Short-acting β₂-agonists and systemic steroids are used for the treatment of acute attacks. All other medications are used for the long-term control of asthma. Patients with severe disease occasionally need to be given oral steroids for long periods of time.

A detailed discussion of the long-term treatment of asthma is beyond the scope of this chapter, and recom-mendations vary among authors. Suggested regimens are as follows:

·  Mild intermittent asthma: short-acting β₂ agonist used on an as-needed basis.

·  Mild persistent asthma: low dose of inhaled steroid or a leukotriene antagonist as a long-term treatment, in addition to a short-acting β₂-agonist inhaler.

·  Moderate persistent asthma: medium dose of inhaled steroid with or without a long-acting β₂-agonist.

·  Severe persistent asthma: high dose of inhaled steroid and a long-acting bronchodilator. In addition, long-term oral steroids are often required. An extended-release theo-phylline can be used to decrease the frequency of attacks and nocturnal symptoms.

Acute attacks not responding to self-administered metered-dose inhaler (MDI) β₂-agonist are usually treated with β₂-agonist nebulizers and systemic steroids (e.g., methylprednisolone 125 mg IV) that will then be tapered over a few days. In case of failure after escalating doses of a β₂-agonist (15 mg of albuterol nebulized over 1 hour), sub-cutaneous epinephrine (0.3 mg q 20 min) can be used with electrocardiogram (ECG) monitoring. Magnesium has been used as a last-resort bronchodilator for refractory bronchospasm.