Pharmacology
Mechanism of action
It is a synthetic prostaglandin analog (or more specifically, an analog of prostaglandin F2α) that works by increasing the outflow of aqueous fluid from the eyes.Like other analogs of prostaglandin F2α such as tafluprost and latanoprost, travoprost is an ester prodrug of the free acid, which acts as an agonist at the prostaglandin F receptor, increasing outflow of aqueous fluid from the eye and thus lowering intraocular pressure. Pharmacokinetics
Travoprost is absorbed through the cornea, where it is hydrolysed to the free travoprost acid. Highest concentrations of the acid in the eye are reached one to two hours after application, and its half-life in the aqueous fluid is 1.5 hours. Once it reaches the bloodstream, it is quickly metabolised, so that concentrations in the system do not exceed 25 pg/ml (compared to 20 ng/ml in the eye, which is higher by nearly a factor of 1000).Metabolites are formed by beta oxidation of the acidic chain (compare Tafluprost#Pharmacokinetics), oxidation of the OH-group in the other side chain, and reduction of the double bond next to this OH-group. Travoprost acid and its metabolites are mainly excreted via the kidney with a terminal half-life of 45 minutes. References
External links
"Travoprost". Drug Information Portal. U.S. National Library of Medicine.
Computed tomography (CT) may be used to confirm the diagnosis. Often the findings are typical enough to allow the doctor to make a diagnosis without ordering additional tests. To confirm the diagnosis, a doctor may perform a lung biopsy using a bronchoscope. Many times, a larger specimen is needed and must be removed surgically. Plain chest radiography shows normal lung volumes, with characteristic patchy unilateral or bilateral consolidation. Small nodular opacities occur in up to 50% of patients and large nodules in 15%. On high resolution computed tomography, airspace consolidation with air bronchograms is present in more than 90% of patients, often with a lower zone predominance. A subpleural or peribronchiolar distribution is noted in up to 50% of patients. Ground glass appearance or hazy opacities associated with the consolidation are detected in most patients. Histologically, cryptogenic organizing pneumonia is characterized by the presence of polypoid plugs of loose organizing connective tissue (Masson bodies) within alveolar ducts, alveoli, and bronchioles. Unusual presentations of organizing pneumonia
While patchy bilateral disease is typical, there are unusual variants of organizing pneumonia where it may appear as multiple nodules or masses. One rare presentation, focal organizing pneumonia, may be indistinguishable from lung cancer based on imaging alone, requiring biopsy or surgical resection to make the diagnosis. Complications
Rare cases of COP have induced with lobar cicatricial atelectasis. Treatment
Systemic steroids are considered the first line treatment for organizing pneumonia, with patients often having clinical improvement within 72 hours of steroid initiation and most patients achieving recovery.