Asthma Medication Side Effects

Possibilities differ depending on the class, dose, and delivery

As with all drugs, there are side effects associated with asthma medications. The range of possibilities is wide, from oral thrush to nervousness to glaucoma and more. Side effects can vary not only by drug class and dose, but by whether the asthma drug is inhaled or taken by mouth.

In most cases, the asthma medications are well-tolerated, and the benefits of treatment outweigh the consequences. There may be times, however, when a side effect is more severe and requires either a dose adjustment or a change of treatment entirely.

Inhaled Corticosteroids

Inhaled corticosteroids (commonly known as inhaled steroids) are prescribed to help prevent the symptoms of asthma. When used regularly, they help decrease the frequency and severity of asthma attacks. However, they will not relieve an attack once it has started.

Inhaled corticosteroids can cause both local side effects (limited to a part of the body) and systemic side effects (affecting the entire body). Systemic effects tend to be more severe and are typically associated with long-term use.

Among the possibilities:

The use of a spacer on the mouthpiece of an inhaler may reduce the risk of side effects from inhaled corticosteroids. Rinsing and gargling after use may also prevent hoarseness and oral thrush.

Short- and Long-Acting Beta Antagonists

Short-acting beta antagonists (SABAs) like albuterol are typically used as rescue medications to provide the quick relief of asthma symptoms. By contrast, long-acting beta-agonists (LABAs) like Severant (salmeterol) continue to work for 12 hours or more.

The side effects are much the same for SABAs and LABAs since the two drug classes share similar mechanisms of action. Side effects include:

  • Increased heart rate
  • Headache
  • Dizziness
  • Anxiety
  • Nervousness or tremors
  • Rash

Though the side effects tend to resolve quickly with SABAs, they can often persist with LABAs. The same can occur when beta antagonists are used excessively.

While the overuse of a rescue inhaler can increase your risk of a severe asthma attack, that risk is multiplied if you overuse a LABA. So serious is the concern that the U.S. Food and Drug Administration (FDA) was prompted to issue a black box warning in 2003 advising consumers about the risk of fatal asthma attacks when using the combination inhaler Advair (fluticasone/salmeterol).

Oral Corticosteroids

Oral corticosteroids are typically used if you have experience or are at risk of a serious asthma attack. While steroids are delivered intravenously in a hospital setting, they are given in oral form if your symptoms are severe but do not require hospitalization.

Side effects are similar to those for inhaled steroids, albeit more common and severe. They include:

  • Weight gain
  • Fluid retention
  • High blood pressure
  • Elevated blood sugar
  • Growth suppression in children
  • Osteoporosis (bone density loss) in adults
  • Muscle weakness
  • Cataracts
  • Glaucoma
  • Type 2 diabetes

If you require an oral steroid like prednisone two or more times per year, your asthma is not being well controlled. See your doctor and discuss whether an adjustment of treatment is needed.

Leukotriene Modifiers

Singulair (montelukast) and other leukotriene modifiers work by blocking a substance called leukotriene, which can trigger bronchoconstriction (narrowing of the airways) leading to an asthma attack.

Leukotriene modifiers are generally well tolerated but do have a number of common side effects, including:

  • Stomach upset
  • Headache
  • Flu-like symptoms
  • Nervousness
  • Nausea or vomiting
  • Nasal congestion
  • Rash

Generally speaking, side effects develop within the first month of treatment. Children using leukotriene modifiers may also experience hyperactivity.

Mast Cell Stabilizers

Cromolyn sodium and Alocril (nedocromil) are mast cell stabilizers used for those with mild persistent asthma. These drugs work by preventing mast cells, a type of white blood cell, from secreting inflammatory substances called histamine into the bloodstream.

Cromolyn sodium and Alocril are generally well tolerated with most side effects decreasing with use. These include:

  • A bad taste in the mouth
  • Cough
  • Itchy or a sore throat
  • Headache
  • Nasal congestion
  • Anaphylaxis (rare)

Anaphylaxis is a whole-body, potentially life-threatening allergic reaction. If not treated immediately, people with anaphylaxis may experience shock, coma, asphyxiation, heart or respiratory failure, and even death.


Xolair (omalizumab) is an immunomodulator delivered by injection. The aim of the treatment to alter the way that the immune system responds to an asthma trigger—essentially preventing it from over-responding.

Because immunomodulators suppress parts of the immune system, you may be prone to frequent mild-to-moderate infections.

Other common side effects include:

  • Swelling and pain at the injection site
  • Itchiness
  • Rash
  • Fatigue
  • Common cold
  • Ear infections
  • Upper respiratory tract infections
  • Sinusitis
  • Acid reflux
  • Headache
  • Sore throat
  • Alopecia (hair loss)
  • Anaphylaxis (rare)

When to Call 911

Call for emergency help if you experience some or all of the following after a mast cell stabilizer or immunomodulator, as these are signs of anaphylaxis:

  • Rash or hives
  • Wheezing
  • Shortness of breath
  • Rapid or irregular heartbeats
  • Dizziness, lightheadedness, or fainting
  • Swelling of the face, tongue, or throat
  • A feeling of impending doom

A Word From Verywell

When used appropriately, asthma medications are safe with side effects that range from mild to manageable. Severe side effects are often associated with the inconsistent use or overuse of asthma medications.

If you do not how to use your asthma medications correctly or are having problems with adherence, speak with your doctor and be honest about what you are experiencing. The same applies if a side effect is persistent or worsening. By working closely with your doctor, you can usually find the right combination of drugs able to control your asthma without significantly impacting your quality of life.

Was this page helpful?
Article Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Heffler E, Madeira LNG, Ferrando M, et al. Inhaled corticosteroids safety and adverse effects in patients with asthma. J Allergy Clin Immunol Pract. 2018;6(3):776-81. doi:10.1016/j.jaip.2018.01.025

  2. Hejazi ME, Shafiifar A, Mashayekhi S, Sattari M. Evaluation of proper usage of glucocorticosteroid inhalers and their adverse effects in asthmatic patientsTanaffos. 2016;15(1):9-16.

  3. Billington CK, Penn RB, Hall IP. β2 AgonistsHandb Exp Pharmacol. 2017;237:23-40. doi:10.1007/164_2016_64

  4. Gerald JK, Carr TF, Wei CY, Holbrook JT, Gerald LB. Albuterol overuse: a marker of psychological distress? J Allergy Clin Immunol Pract. 2015;3(6):957-62. doi:10.1016/j.jaip.2015.06.021

  5. Broadbent C, Pfeffer P, Steed L, Walker S. Patient-reported side effects of oral corticosteroids. Eur Respir J. 2018;52:PA3144. doi:10.1183/13993003.congress-2018.PA3144

  6. Asthma and Allergy Foundation. Oral corticosteroids and asthma. Updated September 2018.

  7. Erdem SB, Nacaroglu HT, Karkiner CSU, Gunay I, Can D. Side effects of leukotriene receptor antagonists in asthmatic children. Iran J Pediatr. 2015;25(5):e3313. doi:10.5812/ijp.3313

  8. Mounsey AL, Gray RE. Topical antihistamines and mast cell stabilizers for treating allergic conjunctivitis. Am Fam Physician. 2016 Jun 1;93(11):915-6.

  9. Cardet JC, Casale TB. New insights into the utility of omalizumab. J Allergy Clin Immunol. 2019;143(3):923-926.e1. doi:10.1016/j.jaci.2019.01.016

  10. Al-Ahmad M, Nurkic J, Maher A, Arifhodzic N, Jusufovic E. Tolerability of omalizumab in ssthma as a major compliance factor: 10-year follow up. Open Access Maced J Med Sci. 2018;6(10):1839-44. doi:10.3889/oamjms.2018.394