Differences Between Inhaled and Oral Corticosteroids for Asthma

In This Article

Inhaled corticosteroids and oral corticosteroids are two forms of a drug central to the treatment of asthma. Corticosteroids, also referred to as steroids, are synthetic medications that suppress the immune system and alleviate inflammation. By controlling inflammation in the airways, the lungs are not only less sensitive to asthma triggers but less likely to experience asthma attacks.

Although inhaled corticosteroids and oral corticosteroids have similar mechanisms of action, they have different indications for use, side effects, and drug interactions.

Mechanisms of Action

Corticosteroids are man-made drugs that mimic the action of the stress hormone cortisol. Cortisol is the hormone secreted by adrenal glands that has potent anti-inflammatory effects.

At times of physical or emotional stress, cortisol can slow the rate by which lymphocytes and other white blood cells replicate. Though these cells are central to the body's immune defense, increased numbers trigger the release of inflammatory proteins known as cytokines, causing redness, swelling, pain, and increased sensitivity in affected tissues.

By mimicking the action of cortisol, corticosteroids can temper inflammation "on-demand" when used locally (topical application, inhalation, or local injection) or systemically (pill, oral liquid, or intravenous infusion).

This action is important in controlling a disease like asthma in which persistent inflammation can increase airway hyperresponsiveness (sensitivity to asthma triggers like allergens, temperature, and environmental irritants). By tempering inflammation, hyperresponsiveness is reduced along with the risk of acute attacks.

Though inhaled and oral corticosteroids work in more or less the same way, they differ in how they are used in the treatment of asthma:

  • Inhaled corticosteroids: Because they are delivered directly to the lungs, inhaled steroids require smaller doses (measured in micrograms, mcg), have fewer side effects, and are safer for long-term use. They are considered the first-line controller medication for people with asthma.
  • Oral corticosteroids: Because they are delivered systemically (via the bloodstream), oral steroids require larger doses (measured in milligrams, mg), have more side effects, and pose greater harms with long-term use. They are reserved for use in more severe cases.

There are different types of inhaled and oral steroids approved for the treatment of asthma in the United States.

Inhaled Corticosteroids
  • Alvesco (ciclesonide)

  • Asmanex (mometasone)

  • Flovent (fluticasone)

  • Pulmicort (budesonide)

  • Qvar (beclomethasone)

Oral Corticosteroids
  • Dexamethasone

  • Methylprednisolone

  • Prednisolone

  • Prednisone

Indications for Use

Inhaled and oral corticosteroids differ in terms of when they are introduced into the asthma treatment plan.

Inhaled Corticosteroids

Inhaled corticosteroids are indicated for use when your asthma is being poorly controlled with a short-acting beta-agonist (SABA), also known as a rescue inhaler.

Inhaled corticosteroids are the treatment of choice for the daily control of symptoms when you have persistent asthma.

Persistent asthma is classified in stages (mild, moderate, severe) and can be diagnosed when you have:

  • Acute asthma symptoms more than two days a week
  • More than three nighttime awakenings per month due to asthma
  • More than twice-weekly use of a rescue inhaler
  • Limitations to normal activities due to asthma

Inhaled corticosteroids can be used in all stages of persistent asthma. As the severity of the disease increases, the steroid dose will also increase.

Oral Corticosteroids

Oral corticosteroids are used either to treat a severe asthma attack or to provide long-term control of severe persistent asthma.

  • Severe asthma attacks (requiring hospitalization or emergency care) are typically treated with an intravenous dose of a corticosteroid drug to bring down the acute inflammation. This will be followed by a short course of oral corticosteroids to help normalize lung function and prevent a repeat attack.
  • Severe persistent asthma is a stage of the disease when your lung function is severely impaired and other asthma medications fail to control your symptoms. In cases like these, oral steroids are prescribed on a daily basis in combination with other medications.

Severe persistent asthma is diagnosed when you meet some or all of several criteria, such as frequent use of a rescue inhaler throughout the day and severely reduced lung function (as measured by an FEV1 value of under 60% of your expected range or a reduction in your FEV1/FVC ratio of more than 5%).

Dosages

Inhaled and oral corticosteroids differ by the amount of drug a person is exposed to with each dose and the duration of treatment.

Inhaled Corticosteroids

Because inhaled corticosteroid doses are relatively small, people with asthma can use these treatments on an ongoing basis with relative safety. Depending on the drug used—as well as the user's age and the severity of symptoms—inhaled steroids may be used once or twice daily.

Different inhaled steroids use different delivery systems:

  • Meter-dosed inhalers (MDIs) use an aerosolized propellant to deliver the steroids into the lungs.
  • Dry powder inhalers (DPIs) require you to suck in the dose with your breath.
  • Nebulizers transform the drug into an aerosolized mist for inhalation and are ideal for babies, younger children, or those with severe breathing problems.
Inhaled Corticosteroids Recommended Dosage
Drug Inhaler Type Approved Ages Standard Dose
Alvesco MDI 12 years and over 1-2 puffs twice daily
Asmanex HFA MDI 12 years and over 2 puffs twice daily
Asmanex Twisthaler DPI 4 years and over 1 puff once daily
Flovent HFA MDI 4 years and over 1-2 puffs twice daily
Flovent Diskus DPI 4 years and over 1-2 puffs twice daily
Pulmicort Flexhaler DPI 6 years and over 2 puffs twice daily
Pulmicort Respules Nebulizer 12 months to 8 years Once or twice daily
Qvar MDI 4 years and older 1-2 puffs twice daily

Oral Corticosteroids

Oral corticosteroids not only expose you to higher doses of the drug but deliver them throughout the entire body. Due to the high risk of side effects, they are reserved for the most severe cases and gradually reduced once you no longer need them.

When used for asthma emergencies, oral corticosteroids are typically prescribed for no longer than five to 10 days. The dose can vary by the drug used but is typically calculated as 1 milligram per kilogram of body weight (mg/kg) with a maximum daily dose of around 50 mg.

When oral corticosteroids are used for the long-term treatment of severe persistent asthma, the dose and duration of treatment can vary by the combination of drugs used.

For example, when an oral corticosteroid is used with a biologic drug such as Xolair (omalizumab), it can often be administered at a lower dose and for a longer period of time. Similarly, a daily inhaled steroid reduces the amount of oral steroid you need to control asthma symptoms.

When used for longer than three weeks, oral corticosteroids need to be gradually tapered to prevent withdrawal, a rebound in symptoms, or a potentially severe condition known as an adrenal crisis. Do this under the guidance of your physician.

Depending on the dose and how long you've used the oral steroid, the tapering process may take weeks or months.

Side Effects

There are generally fewer and less severe side effects with inhaled corticosteroids than with oral corticosteroids. But, this is not always the case.

Common

Side effects of inhaled steroids are generally limited to the upper respiratory tract, although some systemic side effects can occur. Oral steroids can cause a diverse range of side effects impacting multiple organ systems.

Inhaled Corticosteroids
  • Headache

  • Sore throat

  • Hoarseness

  • Oral thrush

  • Sinus infection

  • Bronchitis

  • Common cold

  • Flu

  • Heartburn

  • Muscle aches

Oral Corticosteroids
  • Headache

  • Trouble sleeping

  • Dizziness

  • Agitation

  • Weight gain

  • Acne

  • Muscle weakness

  • Nausea and vomiting

  • Trouble concentrating

  • Swelling of the extremities

  • Numbness or tingling in the hands or feet

  • Pounding in the ears

  • Irregular heartbeat

  • Changes in vision

Severe

Although inhaled steroids pose a lesser risk of side effects than oral ones, this should not suggest that they pose no risks.

Inhaled and oral corticosteroids can cause immune suppression, increasing your risk for common and uncommon infections. They can also cause hormonal imbalances by impairing the function of the adrenal glands.

Prolonged exposure to corticosteroids, whether inhaled or oral, can also inhibit bone growth and cause irreversible changes in your vision.

Oral Corticosteroid Side Effects
  • Weight gain

  • Urinary problems

  • Swelling of the extremities

  • Irregular heartbeat

  • Irregular periods

  • Vomiting and/or diarrhea

  • Mood changes

  • Changes in skin pigmentation

  • Impaired growth in children

  • Osteopenia (bone loss)

  • Glaucoma (caused by damage to the optic nerve)

  • Cataracts (clouding of the eye lens)

Inhaled Corticosteroid Side Effects
  • Abnormal facial hair

  • Stomach ulcers

  • Missed or absent periods

  • Glaucoma

  • Cataracts

  • Obesity

  • New onset of diabetes

  • Personality changes

  • Stunted growth in children

  • Redistribution of body fat

  • Thinning of skin

  • Facial swelling ('moon face")

  • Osteoporosis (porous bones)

  • Bone fractures

  • Convulsions or seizures

  • Increased risk of heart attack and congestive heart failure

  • Pulmonary edema (fluid in the lungs)

Drug Interactions

Both inhaled and oral steroids utilize a liver enzyme called cytochrome P450 (CYP450) for metabolization. Other drugs that also use CYP450 for metabolization can interact with corticosteroids as they "compete" for the available enzyme. This can cause adverse increases or decreases of one or both drugs in the bloodstream.

Some of the more significant CYP450 interactions involve the following classes of drugs:

Though inhaled steroids can interact with many of the same drugs as oral steroids, the interactions may not be significant enough to require an adjustment in treatment.

By contrast, oral steroids are more likely to cause significant interactions due to their higher doses. These interactions may require a dose adjustment, a drug substitution, or a separation of doses by one or several hours.

Oral corticosteroids can also interact with specific drugs that are less commonly affected by inhaled corticosteroids, including:

To avoid interactions, always advise your doctor about any drugs you are taking, whether they are prescription, over-the-counter, herbal, or recreational.

A Word From Verywell

Corticosteroid drugs can be extremely effective in the treatment of asthma if used a prescribed. Always keep to a strict schedule when taking a steroid, spacing your doses equally to ensure you neither have too little or too much of the drug in your system at one time.

Never increase or decrease a corticosteroid dose without first speaking to your doctor. Larger doses don't always afford better results, and lower doses may end up causing withdrawal symptoms and other harmful effects.

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