Molecule

Drug Groups

approved

Description

A muscarinic antagonist structurally related to atropine but often considered safer and more effective for inhalation use. It is used for various bronchial disorders, in rhinitis, and as an antiarrhythmic. [PubChem]

Indication

For maintenance treatment of bronchospasm associated with chronic obstructive pulmonary disease, including chronic bronchitis and emphysema.

Pharmacology

Ipratropium bromide, a synthetic ammonium compound structurally similar to atropine, is used as a bronchodilator in the management of cholinergic-mediated bronchospasm associated with chronic obstructive pulmonary disease and in the treatment of rhinorrhea associated with the common cold or with allergic or nonallergic seasonal rhinitis.

Toxicity

LD₅₀=1001mg/kg (orally in mice)

Affected Organisms

Biotransformation

Partially metabolized to at least 8 metabolites formed primarily via hydrolysis and conjugation. The main metabolites are N-isopropylnortropium methobromide, which is formed by enzymatic hydrolysis of the ester; α-phenylacrylic acid-N-isopropylnortropine-ester methobromide, which is formed by enzymatic loss of a water; and phenylacetic acid-N-isopropylnortropine-ester methobromide, which is formed by enzymatic loss of a CH₃OH-group. These metabolites appear to be inactive.

Absorption

Inhalation (local)-minimal; Nasal-rapid and minimal

Half Life

2-4 hours after administration orally, IV or by oral inhalation (radiolabeled ipratropium bromide assay measures parent drug and its metabolites). Using a radioreceptor assay that measures only unchanged ipratropium bromide, the initial distribution-phase half-life (t_{1/2 α}) and terminal elimination-phase half-life (t_{1/2 β}) were 0.07 and 1.6 hours, respectively, following a single 2 mg IV dose of the drug in healthy adults.

Protein Binding

Minimally (0 to 9% in vitro) bound to plasma albumin and α1-acid glycoproteins

Elimination

Primarily eliminated renally via active secretion.

Distribution

* 4.6 L/kg

Clearance

* 2.3 L/min (total clearance of active ingredient)

References

External Links