Editing Bronchodilator

{{Short description|Drug which widens the lung airways}}
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| specialty    = [[Pulmonology]]
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A '''bronchodilator''' or '''broncholytic'''<ref>{{Cite book | url=https://books.google.com/books?id=OA37DQAAQBAJ&q=broncholytic+bronchodilator+dictionary&pg=PA320 | title=Taber's Cyclopedic Medical Dictionary| isbn=9780803659407| last1=Venes| first1=Donald| date=2017-01-25| publisher=F.A. Davis}}</ref> (although the latter occasionally includes [[Mucus#Mucus hypersecretion|secretory]] inhibition as well) is a substance that dilates the [[Bronchus|bronchi]] and [[bronchiole]]s, decreasing resistance in the [[respiratory system|respiratory airway]] and increasing airflow to the [[lung]]s. Bronchodilators may be [[endogenous|originating naturally within the body]], or they may be [[medication]]s administered for the treatment of breathing difficulties, usually in the form of [[inhaler]]s. They are most useful in [[obstructive lung disease]]s, of which [[asthma]] and [[chronic obstructive pulmonary disease]] are the most common conditions. They may be useful in [[bronchiolitis]] and [[bronchiectasis]], although this remains somewhat controversial. They are often prescribed but of unproven significance in [[restrictive lung disease]]s.<ref name="SatheKrishnaswami2015">{{cite journal | vauthors = Sathe NA, Krishnaswami S, Andrews J, Ficzere C, McPheeters ML | title = Pharmacologic Agents That Promote Airway Clearance in Hospitalized Subjects: A Systematic Review | journal = Respiratory Care | volume = 60 | issue = 7 | pages = 1061–70 | date = July 2015 | pmid = 25944943 | doi = 10.4187/respcare.04086 | s2cid = 7017557 | url = http://rc.rcjournal.com/content/respcare/60/7/1061.full.pdf | doi-access = free }}</ref>

Bronchodilators are either short-acting or long-acting. Short-acting medications provide quick or "rescue" relief from acute [[bronchoconstriction]]. Long-acting bronchodilators help to control and prevent symptoms. The three types of prescription bronchodilating drugs are [[Beta2-adrenergic agonist|beta-2 adrenergic agonists]] (short- and long-acting), [[anticholinergics]] (short- and long-acting), and [[theophylline]] (long-acting).

==Short-acting β<sub>2</sub>-adrenergic agonists==
These are quick-relief or "rescue" medications that provide quick, temporary relief from asthma symptoms or flare-ups. These medications usually take effect within 20 minutes or less, and can last from four to six hours. These inhaled medications are best for treating sudden and severe or new asthma symptoms. Taken 15 to 20 minutes ahead of time, these medications can also prevent asthma symptoms triggered by exercise or exposure to cold air. Some short-acting β-agonists, such as [[salbutamol]], are specific to the lungs; they are called β<sub>2</sub>-adrenergic agonists and can relieve bronchospasms without unwanted [[cardiac]] side effects of nonspecific β-agonists (for example, [[ephedrine]] or [[epinephrine]]). Patients who regularly or frequently need to take a short-acting β<sub>2</sub>-adrenergic agonist should consult their doctor, as such usage indicates uncontrolled asthma, and their routine medications may need adjustment.{{citation needed|date=February 2022}}

==Long-acting β<sub>2</sub>-adrenergic agonists==
{{main article|Long-acting beta-adrenoceptor agonist}}
These are long-term medications taken routinely in order to control and prevent bronchoconstriction. They are not intended for fast relief. These medications may take longer to begin working, but relieve airway constriction for up to 12 hours.
Commonly taken twice a day with an anti-inflammatory medication, they maintain open airways and prevent asthma symptoms, particularly at night.{{citation needed|date=February 2022}}

[[Salmeterol]] and [[formoterol]] are examples of these.

==Anticholinergics==
{{main article|Anticholinergics}}

Some examples of anticholinergics are [[tiotropium]] (Spiriva) and [[ipratropium|ipratropium bromide]].{{citation needed|date=February 2022}}

Tiotropium is a long-acting, 24-hour, anticholinergic bronchodilator used in the management of [[chronic obstructive pulmonary disease]] (COPD).

Only available as an inhalant, ipratropium bromide is used in the treatment of asthma and COPD. As a short-acting anticholinergic, it improves lung function and reduces the risk of exacerbation in people with symptomatic asthma.<ref>{{cite journal | vauthors = Price D, Fromer L, Kaplan A, van der Molen T, Román-Rodríguez M | title = Is there a rationale and role for long-acting anticholinergic bronchodilators in asthma? | journal = npj Primary Care Respiratory Medicine | volume = 24 | issue = 1 | pages = 14023 | date = July 2014 | pmid = 25030457 | doi = 10.1038/npjpcrm.2014.23 | pmc = 4373380 }}</ref> However, it will not stop an asthma attack already in progress. Because it has no effect on asthma symptoms when used alone, it is most often paired with a short-acting β<sub>2</sub>-adrenergic agonist. While it is considered a relief or rescue medication, it can take a full hour to begin working. For this reason, it plays a secondary role in acute asthma treatment. Dry throat is the most common side effect. If the medication gets in contact with the eyes, it may cause blurred vision for a brief time.

The use of anticholinergics in combination with short-acting β<sub>2</sub>-adrenergic agonists has been shown to reduce hospital admissions in children and adults with acute asthma exacerbations.<ref>{{cite journal | vauthors = Rodrigo GJ, Castro-Rodriguez JA | title = Anticholinergics in the treatment of children and adults with acute asthma: a systematic review with meta-analysis | journal = Thorax | volume = 60 | issue = 9 | pages = 740–6 | date = September 2005 | pmid = 16055613 | pmc = 1747524 | doi = 10.1136/thx.2005.040444 }}</ref><ref>{{cite journal | vauthors = Griffiths B, Ducharme FM | title = Combined inhaled anticholinergics and short-acting beta2-agonists for initial treatment of acute asthma in children | journal = Paediatric Respiratory Reviews | volume = 14 | issue = 4 | pages = 234–5 | date = December 2013 | pmid = 24070913 | doi = 10.1016/j.prrv.2013.08.002 }}</ref>

==Other==
Available in oral and injectable form, [[theophylline]] is a long-acting bronchodilator that prevents asthma episodes. It belongs to the chemical class [[methylxanthine]]s (along with caffeine). It is prescribed in severe cases of asthma or those that are difficult to control. It must be taken 1–4 times daily, and doses cannot be missed. Blood tests are required to monitor therapy and to indicate when dosage adjustment is necessary. Side effects can include nausea, vomiting, diarrhea, stomach or headache, rapid or irregular heart beat, muscle cramps, nervous or jittery feelings, and hyperactivity. These symptoms may signal the need for an adjustment in medication. It may promote [[Gastroesophageal reflux disease|acid reflux]], also known as GERD, by relaxing the lower esophageal sphincter muscle. Some medications, such as seizure and ulcer medications and antibiotics containing [[erythromycin]], can interfere with the way theophylline works. Coffee, tea, colas, cigarette-smoking, and viral illnesses can all affect the action of theophylline and change its effectiveness. A physician should monitor dosage levels to meet each patient's profile and needs.

Additionally, some [[psychostimulant]] drugs that have an amphetamine like mode of action, such as [[amphetamine]],<ref>[https://web.archive.org/web/20080720082430/http://www.medic8.com/medicines/Amphetamine.html Amphetamine] is listed as having medical uses as bronchodilator. Medic8</ref> [[methamphetamine]], and [[cocaine]],<ref>{{cite book | first = Dominic | last = Streatfeild | name-list-style = vanc | title = Cocaine: An Unauthorized Biography | url = https://books.google.com/books?id=9ceLzaeHsZAC&pg=PA110 | access-date = 14 February 2011 | date = 17 June 2003 | publisher = Macmillan | isbn = 978-0-312-42226-4 | pages = 110 }}</ref> have bronchodilating effects and were used often for [[asthma]] due to the lack of effective β<sub>2</sub>-adrenergic agonists for use as bronchodilator, but are now rarely, if ever, used medically for their bronchodilatory effects.

Gaseous [[carbon dioxide]] also relaxes airway musculature: [[hypocapnia]] caused by deliberate [[hyperventilation]] increases respiratory resistance while [[hypercapnia]] induced by carbon dioxide inhalation reduces it;<ref>{{Cite journal |last1=van den Elshout |first1=F. J. |last2=van Herwaarden |first2=C. L. |last3=Folgering |first3=H. T. |date=January 1991 |title=Effects of hypercapnia and hypocapnia on respiratory resistance in normal and asthmatic subjects. |journal=Thorax |volume=46 |issue=1 |pages=28–32 |doi=10.1136/thx.46.1.28 |issn=0040-6376 |pmc=1020910 |pmid=1908137}}</ref> however, this bronchodilating effect of carbon dioxide inhalation only lasts 4 to 5 minutes.<ref>{{Cite journal |last1=Fisher |first1=H. K. |last2=Hansen |first2=T. A. |date=November 1976 |title=Site of action of inhaled 6 per cent carbon dioxide in the lungs of asthmatic subjects before and after exercise |url=https://www.atsjournals.org/doi/10.1164/arrd.1976.114.5.86 |journal=The American Review of Respiratory Disease |volume=114 |issue=5 |pages=861–870 |doi=10.1164/arrd.1976.114.5.861 |doi-broken-date=1 November 2024 |issn=0003-0805 |pmid=984580}}</ref> Nonetheless, this observation has inspired the development of [[S-1226]], carbon dioxide-enriched air formulated with [[Nebulizer|nebulized]] [[perflubron]].<ref>{{Cite journal |last1=Green |first1=Francis H. Y. |last2=Leigh |first2=Richard |last3=Fadayomi |first3=Morenike |last4=Lalli |first4=Gurkeet |last5=Chiu |first5=Andrea |last6=Shrestha |first6=Grishma |last7=ElShahat |first7=Sharif G. |last8=Nelson |first8=David Evan |last9=El Mays |first9=Tamer Y. |last10=Pieron |first10=Cora A. |last11=Dennis |first11=John H. |date=2016-07-28 |title=A phase I, placebo-controlled, randomized, double-blind, single ascending dose-ranging study to evaluate the safety and tolerability of a novel biophysical bronchodilator (S-1226) administered by nebulization in healthy volunteers |journal=Trials |volume=17 |pages=361 |doi=10.1186/s13063-016-1489-8 |issn=1745-6215 |pmc=4964056 |pmid=27464582 |doi-access=free }}</ref>

==Common bronchodilators==
The bronchodilators are divided into short- and long-acting groups. Short-acting bronchodilators are used for relief of bronchoconstriction, while long-acting bronchodilators are predominantly used for prevention.

Short-acting bronchodilators include:
* [[Salbutamol]]/albuterol (Proventil or Ventolin)
* [[Levosalbutamol]]/levalbuterol (Xopenex)
* [[Pirbuterol]] (Maxair)
* [[Epinephrine]] (Primatene Mist)
* [[Racemic epinephrine|Racemic Epinephrine]] (Asthmanefrin, Primatene Mist Replacement)
* [[Ephedrine]] (Bronkaid)
* [[Terbutaline]]

Long-acting bronchodilators include:
* [[Salmeterol]] (Serevent or Seretide)
* [[Clenbuterol]] (Spiropent)
* [[Formoterol]]
* [[Bambuterol]]
* [[Indacaterol]]

== References ==
{{Reflist}}

== External links ==
* [https://www.nlm.nih.gov/medlineplus/druginformation.html Drug information]

{{Major Drug Groups}}
{{Drugs for obstructive airway diseases}}
{{Respiratory physiology}}
{{Authority control}}

[[Category:Bronchodilators| ]]
[[Category:Respiratory physiology]]
[[Category:Respiratory therapy]]
[[Category:Pulmonary function testing]]