Bronchodilator medicines

Bronchodilators are medicines that open up the small airways of the lungs (bronchi) to make breathing easier.

They are often used to treat conditions that can cause the airways to become narrow or inflammed (swollen), such as:

How they work

Bronchodilator drugs relax the muscles in the lungs, which allows the airways to widen and makes breathing easier. Some bronchodilators also help to clear mucus and reduce inflammation in the lungs. For more information, see bronchodilator drugs - how they work.

Types of bronchodilator

Bronchodilators are often inhaled, but are also available as tablets, syrup and an injection. There are two types:

  • short-acting bronchodilators - these provide short-term relief from breathlessness
  • long-acting bronchodilators - these have no immediate effect, but can help control the symptoms of conditions such as asthma if used regularly, and have more long-lasting effects

The three most widely used bronchodilators are:

  • beta-2 agonists
  • anticholinergics
  • theophylline

Beta-2 agonists

Beta-2 agonists are available in short-acting and long-acting varieties, and are usually taken through an inhaler.

They relax the muscles in the lungs, which allows the airways to widen. Long-acting beta-2 agonists can also reduce the amount of mucus in the lungs by speeding up the motion of cilia. Cilia are tiny hairs that line the walls of your airways and help 'sweep' mucus out of the airways.

Beta-2 agonists tend to be more effective in treating asthma than in treating chronic obstructive pulmonary disease (COPD).

Anticholinergics

Like beta-2 agonists, anticholinergics also relax the muscles in the lungs. Short-acting and long-acting varieties are available. Anticholinergics are mainly used to treat COPD.

Anticholinergics are usually taken through an inhaler, but people with severe COPD will need to use a nebuliser. This device uses air pressure to turn the medicine into a fine mist, which is then breathed in through a mask.

Theophylline

Theophylline is a long-acting bronchodilator that is usually used in the treatment of COPD. Exactly how theophylline works is unclear, but it seems to relax the muscles in the lungs, while reducing any possible inflammation (swelling) in the airways.

Theophylline is mostly taken in tablet or syrup form. Due to a risk of associated side effects (see bronchodilator drugs - side effects), theophylline is normally only used as a treatment if other bronchodilators are not effective.

When to avoid bronchodilators

Anticholinergics

Anticholinergics are not recommended in people with:

  • prostate problems, such as prostate cancer or benign prostatic hyperplasia (a non-cancerous swelling of the prostate), because anticholinergics can cause problems with urinating
  • chronic glaucoma (a build-up of pressure in the eye that can lead to blindness)

Theophylline

Theophylline is usually not recommended for people with a history of liver disease. This is because their liver may not be able to remove the medicine from their body.

Using bronchodilators with caution

Generally, bronchodilators should be used with caution in the elderly and in people with epilepsy or a peptic ulcer. These people will have to be monitored regularly by their GP.

Further considerations are outlined below.

Beta-2 agonists

Beta-2 agonists should be used with caution in people with:

  • overactive thyroid (hyperthyroidism), as the medication may stimulate the thyroid gland and make the thyroid problem worse
  • heart disease, as the medication may affect blood pressure and cause an irregular heartbeat
  • diabetes, as there is a risk of ketoacidosis (a build-up of acids in your blood) your blood glucose levels may need to be regularly monitored

These people will have to be monitored regularly by their GP.

Theophylline

Theophylline should be used with caution in people with:

  • overactive thyroid (hyperthyroidism), as the medication may stimulate the thyroid gland and make the thyroid problem worse
  • heart disease, as the medication may affect blood pressure and cause an irregular heartbeat

These people will have to be monitored regularly by their GP.

Pregnancy and breastfeeding

Talk to your doctor as soon as possible if you regularly take bronchodilator drugs and are pregnant or breastfeeding. Ideally, you should talk to your doctor before you start trying for a baby or as soon as you find out you are pregnant.

Medication to treat asthma is usually considered safe to use during pregnancy and when you are breastfeeding. Asthma itself can affect your pregnancy, so it needs to be well controlled.

If possible, bronchodilator drugs should be inhaled to minimise your unborn baby's exposure to the medication.

Beta-2 agonists

Beta-2 agonists can affect other muscles as well as the lungs, which can lead to possible side effects.

The most common side effects of beta-2 agonists are nervousness, restlessness and trembling. Some people also find they get a dry, irritated throat after using the medication.

Less common side effects include:

  • muscle cramps
  • a rapid or irregular heartbeat
  • headaches
  • coughing
  • skin rash
  • sleep problems

All side effects should resolve quickly and disappear completely once you have been using the medicine for a few days or weeks. Contact your GP if they do not go away, as your dosage may need to be changed.

Anticholinergics

Compared with beta-2 agonists, anticholinergics are better tolerated by most people, and serious side effects are rare.

A dry mouth is the most commonly reported side effect.

Less common side effects include:

  • nausea
  • coughing
  • headaches
  • constipation
  • palpitations (sensation of a pounding or racing heart)
  • not being able to urinate
  • skin rash
  • blurred vision

Theophylline

Theophylline can cause serious side effects if too much of it builds up in your body. You will need regular blood tests to ensure that the levels of theophylline in your body are safe.

Older people are more at risk of developing side effects from theophylline because their liver may not be able to remove the medicine from their body.

Possible side effects of theophylline include:

  • a rapid heart beat
  • trembling and palpitations
  • restlessness and nervousness
  • nausea
  • headaches
  • dizziness
  • sleep problems
  • seizures (fits)

If you have any of these side effects, contact your GP as your dose will need to be reviewed.

Bronchodilator drugs may interact with a number of other medicines, which could affect the way they work or increase your risk of side effects. Drugs that may interact with bronchodilators include some:

  • beta-blockers
  • antidepressants, including monoamine oxidase inhibitors (MAOIs) and tricyclic antidepressants
  • drugs used to treat Alzheimer's disease
  • drugs taken to lower potassium levels, such as certain diuretics

Always check with your GP or pharmacist before taking a bronchodilator drug with any other prescription or over-the-counter medicine.

Content provided by NHS Choices www.nhs.uk and adapted for Ireland by the Health A-Z.

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