What is budesonide inhaler, and how does it work (mechanism of action)?

Budesonide is a man-made glucocorticoid steroid related to the naturally-occurring hormone, cortisol or hydrocortisone which is produced in the adrenal glands. It is used for treating asthma by inhalation. Glucocorticoid steroids such as cortisol or budesonide have potent anti-inflammatory actions that reduces inflammation and hyper-reactivity (spasm) of the airways caused by asthma. When used as an inhaler, the budesonide goes directly to the inner lining of the inflamed airways to exert its effects. Only 39% of an inhaled dose of budesonide is absorbed into the body, and the absorbed budesonide contributes little to the effects on the airways. While some improvement in the symptoms of asthma may occur within 24 hours, it may take a few weeks to obtain the maximum therapeutic benefits of budesonide when used to treat asthma.

What brand names are available for budesonide inhaler?

Pulmicort, Pulmicort Flexhaler

Is budesonide inhaler available as a generic drug?


Do I need a prescription for budesonide inhaler?


What are the side effects of budesonide inhaler?

  • The most commonly noted side effects associated with inhaled budesonide are mild cough or wheezing; these effects may be minimized by using a bronchodilator inhaler, for example, albuterol (Ventolin HFA), prior to the budesonide.
  • Oral candidiasis or thrush (a fungal infection of the throat) may occur in 1 in 25 persons who use budesonide without a spacer device on the inhaler. The risk is even higher with large doses, but is less in children than in adults.
  • Hoarseness or sore throat also may occur in 1 in 10 persons. Using a spacer device on the inhaler and washing the mouth out with water following each use reduces the risk of both thrush and hoarseness.
  • Less commonly, alterations in voice may occur.

High doses of inhaled glucocorticoid steroids may decrease the formation and increase the breakdown of bone leading to weakened bones and ultimately osteoporosis and fractures. High doses may suppress the body’s ability to make its own natural glucocorticoid in the adrenal gland. It is possible that these effects are shared by budesonide. People with suppression of their adrenal glands (which can be tested for by the doctor) need increased amounts of glucocorticoid steroids orally or intravenously during periods of high physical stress, for example, during infections, to prevent serious illness and shock.

Hypersensitivity reactions, which have been reported with the issue of inhaled budesonide include

Use of budesonide should be discontinued if such reactions occur.

What is the dosage for budesonide inhaler?

Budesonide is used to prevent asthmatic attacks and should not be used to treat an acute attack of asthma.

The Pulmicort Flexhaler

  • The Pulmicort Flexhaler is used for individuals six years of age or older.
  • Effects can be seen within 24 hours, but maximum effects may not be seen for 1-2 weeks or longer.
  • Doses vary widely.
  • Adults usually receive 2 to 4 puffs twice daily.
  • The starting dose for also is 2 to 4 puffs twice daily.
  • For those with mild asthma, treatment once daily may be sufficient.


  • Pulmicort is used for individuals 12 months to eight years of age.
  • Effects are seen in 2 to 8 days, but maximum effects may not be seen for up to 4 to 6 weeks.
  • The usual dose is 0.5-1 mg daily taken in one or two divided doses. A lower starting dose of 0.25 mg once a day may be sufficient in some individuals.

Asthma Symptoms, Causes, and Medications

Which drugs or supplements interact with budesonide inhaler?

When budesonide is given with strong liver enzyme inhibitors (CYP 3A4 inhibitors) such as ketoconazole and other drugs including ritonavir (Norvir), atazanavir (Reyataz), clarithromycin (Biaxin, Biaxin XL), indinavir (Crixivan), itraconazole (Sporanox, Onmel), nefazodone, nelfinavir (Viracept), saquinavir (Invirase) and telithromycin (Ketek), the concentration in blood of budesonide may rise increasing the probability of an individual experiencing more side effects.

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Is budesonide inhaler safe to take if I’m pregnant or breastfeeding?

When given orally to animals, glucocorticoid steroids similar to budesonide have been shown to cause fetal abnormalities. Studies of pregnant women using inhaled budesonide during early pregnancy, however, do not show an increase in the rate of fetal abnormalities. Nevertheless, since these studies cannot exclude the possibility of rare effects on the fetus, inhaled budesonide should be used with caution during pregnancy.

Budesonide like other drugs of its class is secreted in breast milk. It is not known whether the small amounts that may appear in breast milk have effects on the infant. Nevertheless, the benefits of breastfeeding an infant should be weighed against the possible risks associated with using budesonide in a nursing mother.

What else should I know about budesonide inhaler?

What preparations of budesonide inhaler are available?
  • Pulmicort Flexhaler (powder for inhalation), 90 mcg/act, 180 mcg/act.
  • Pulmicort (inhalation suspension), 0.25 mg/2ml, 0.5 mg/2ml suspension, and 1 mg/2ml
How should I keep budesonide inhaler stored?

Budesonide should be stored at room temperature, 20 C – 25 C (68 F – 77 F).

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Medically Reviewed on 12/10/2018


Medically reviewed by John P. Cunha, DO, FACOEP; Board Certified Emergency Medicine


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