Ipratropium bromide

Ipratropium bromide
ATC Code C01CX10, R01AX03, R03BB01
Formula C20H30BrNO3
Molar Mass (g·mol−1) 412,37
Physical State solid
Melting Point (°C) 230–232
CAS Number 22254-24-6
PUB Number 657308
Drugbank ID DB00332
Solubility moderate in water / poor in ethanol


Ipratropium bromide is a medication that opens the middle and large airways in the lungs. It is used to treat the symptoms of chronic obstructive pulmonary disease and asthma. It is a quaternary ammonium derivative of atropine, which belongs to the group of anticholinergics. It is usually administered by inhalation, which provides a local effect without significant systemic side effects.



Ipratropium, due to its structural relationship to the neurotransmitter acetylcholine, acts as an antagonist of the muscarinic acetylcholine receptor. This effect causes the inhibition of the parasympathetic nervous system in the respiratory tract, thus inhibiting its function. The function of the parasympathetic nervous system in the airways is to produce bronchial secretions and constriction, and therefore inhibition of this effect can lead to bronchodilation and decreased secretions. As a result, breathing is facilitated.


Protein binding of ipratropium is very low as the level of circulating ipratropium is minimal. The bound state accounts for only 0-9% of the administered dose. Ipratropium is metabolized in the gastrointestinal tract by the activity of cytochrome P-450 isozymes. Approximately 80-100% of the administered dose of ipratropium is excreted in the urine, with less than 20% of the dose eliminated in the feces. Ipratropium has a short half-life of approximately 1.6 hours.

Drug Interactions

Interactions with other anticholinergics such as tricyclic antidepressants, anti-Parkinsonian agents, and quinidine, which theoretically potentiate side effects, are clinically irrelevant when ipratropium is administered as an inhalant because the systemic blood plasma concentration of ipratropime is very low.


Side effects

Common side effects include dry mouth, cough, and inflammation of the respiratory tract. Potentially serious side effects include urinary retention, worsening respiratory spasms, and a severe allergic reaction. Use during pregnancy and lactation is generally considered safe.

Toxicological Data

LD50 (rat, oral): 1663 mg-kg-1


  • Drugbank
  • PubChem
  • Aktories, Förstermann, Hofmann, Starke: Allgemeine und spezielle Pharmakologie und Toxikologie, Elsvier, 2017
Markus Falkenstätter

Markus Falkenstätter

Markus Falkenstätter ist Autor zu pharmazeutischen Themen in der Medizin-Redaktion von Medikamio. Er befindet sich im letzten Semester seines Pharmaziestudiums an der Universität Wien und liebt das wissenschaftliche Arbeiten im Bereich der Naturwissenschaften.

Mag. pharm Stefanie Lehenauer

Mag. pharm Stefanie Lehenauer

Stefanie Lehenauer ist seit 2020 freie Autorin bei Medikamio und studierte Pharmazie an der Universität Wien. Sie arbeitet als Apothekerin in Wien und ihre Leidenschaft sind pflanzliche Arzneimittel und deren Wirkung.

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