The use of exhaled nitric oxide levels (FeNO) to guide asthma medication dosing may have small benefits for preventing asthma attacks but the potential benefits are not strong enough for this approach to be universally recommended as a method to guide asthma therapy in adults or children.When asthma is unresponsive to usual medications, other options are available for both emergency management and prevention of flareups. Additional options include:

Humidified Oxygen to alleviate hypoxia if saturations fall below 92%. Corticosteroid by mouth are recommended with five days of prednisone being the same 2 days of dexamethasone. One review recommended a seven-day course of steroids. Magnesium sulfate intravenous treatment increases bronchodilation when used in addition to other treatment in moderate severe acute asthma attacks. In adults intravenous treatment results in a reduction of hospital admissions. Low levels of evidence suggest that inhaled (nebulised) magnesium sulfate may have a small benefit for treating acute asthma in adults. Overall, high quality evidence do not indicate a large benefit for combining magnesium sulfate with standard inhaled treatments for adults with asthma. Heliox, a mixture of helium and oxygen, may also be considered in severe unresponsive cases. Intravenous salbutamol is not supported by available evidence and is thus used only in extreme cases. Methylxanthines (such as theophylline) were once widely used, but do not add significantly to the effects of inhaled beta-agonists. Their use in acute exacerbations is controversial.
For children over 2 years old with acute asthma symptoms, inhaled anticholinergic medications taken alone is safe but is not as effective as inhaled SABA or SABA combined with inhaled anticholinergic medication. Adults who receive combined inhaled medications that includes short-acting anticholinergics and SABA may be at risk for increased adverse effects such as experiencing a tremor, agitation, and heart beat palpitations compared to people who are treated with SABA by itself. Older, less selective adrenergic agonists, such as inhaled epinephrine, have similar efficacy to SABAs. They are however not recommended due to concerns regarding excessive cardiac stimulation. Corticosteroids can also help with the acute phase of an exacerbation because of their antiinflamatory properties. The benefit of systemic and oral corticosteroids is well established. Inhaled or nebulized corticosteroids can also be used. For adults and children who are in the hospital due to acute asthma, systemic (IV) corticosteroids improve symptoms. A short course of corticosteroids after an acute asthma exacerbation may help prevent relapses and reduce hospitalizations. Other remedies, less established, are intravenous or nebulized magnesium sulfate and helium mixed with oxygen. Aminophylline could be used with caution as well. Mechanical ventilation is the last resort in case of severe hypoxemia. Intravenous administration of the drug aminophylline does not provide an improvement in bronchodilation when compared to standard inhaled beta-2 agonist treatment. Aminophylline treatment is associated with more adverse effects compared to inhaled beta-2 agonist treatment. Long–term control
Corticosteroids are generally considered the most effective treatment available for long-term control.