"The US Food and Drug Administration (FDA) has approved the long-acting muscarinic antagonist tiotropium bromide (Spiriva Respimat, Boehringer Ingelheim) for long-term maintenance treatment of asthma in people aged 12 years and older, accor"...
Triamcinolone acetonide is a more potent derivative of triamcinolone. Although triamcinolone itself is approximately one to two times as potent as prednisone in animal models of inflammation, triamcinolone acetonide is approximately 8 times more potent than prednisone.
The precise mechanism of the action of glucocorticoids in asthma is unknown. However, the inhaled route makes it possible to provide effective local anti-inflammatory activity with reduced systemic corticosteroid effects. Though highly effective for asthma, glucocorticoids do not affect asthma symptoms immediately. While improvement in asthma may occur as soon as one week after initiation of Azmacort (triamcinolone acetonide (inhalation aerosol)) Inhalation Aerosol therapy, maximum improvement may not be achieved for 2 weeks or longer.
Based upon intravenous dosing of triamcinolone acetonide phosphate ester, the half-life of triamcinolone acetonide was reported to be 88 minutes. The volume of distribution (Vd) reported was 99.5 L (SD ± 27.5) and clearance was 45.2 L/hour (SD ± 9.1) for triamcinolone acetonide. The plasma half-life of glucocorticoids does not correlate well with the biologic half-life.
The pharmacokinetics of radiolabeled triamcinolone acetonide [14C] were evaluated following a single oral dose of 800 mcg to healthy male volunteers. Radiolabeled triamcinolone acetonide was found to undergo relatively rapid absorption following oral administration with maximum plasma triamcinolone acetonide and [14C]-derived radioactivity occurring between 1.5 and 2 hours. Plasma protein binding of triamcinolone acetonide appears to be relatively low and consistent over a wide plasma triamcinolone acetonide concentration range as a function of time. The overall mean percent fraction bound was approximately 68%.
The metabolism and excretion of triamcinolone acetonide were both rapid and extensive with no parent compound being detected in the plasma after 24 hours post-dose and a low ratio (10.6%) of parent compound AUC0-∞ to total [14C] radioactivity AUC0-∞. Greater than 90% of the oral [14C]-radioactive dose was recovered within 5 days after administration in 5 out of the 6 subjects in the study. Of the recovered [14C]-radioactivity, approximately 40% and 60% were found in the urine and feces, respectively.
Three metabolites of triamcinolone acetonide have been identified. They are 6β- hydroxytriamcinolone acetonide, 21-carboxytriamcinolone acetonide and 21-carboxy-6β- hydroxytriamcinolone acetonide. All three metabolites are expected to be substantially less active than the parent compound due to (a) the dependence of anti-inflammatory activity on the presence of a 21-hydroxyl group, (b) the decreased activity observed upon 6-hydroxylation, and (c) the markedly increased water solubility favoring rapid elimination. There appeared to be some quantitative differences in the metabolites among species. No differences were detected in metabolic pattern as a function of route of administration.
Double-blind, placebo-controlled efficacy and safety studies have been conducted in asthma patients with a range of asthma severities, from those patients with mild disease to those with severe disease requiring oral steroid therapy.
The efficacy and safety of Azmacort (triamcinolone acetonide (inhalation aerosol)) Inhalation Aerosol given twice daily was demonstrated in two placebo-controlled clinical trials. In two separate studies, 222 asthmatic patients were randomized to receive either Azmacort (triamcinolone acetonide (inhalation aerosol)) Inhalation Aerosol 300 mcg twice daily or matching placebo for a treatment period of 6 weeks. Patients were adult asthmatics who were using inhaled beta2-agonists on more than an occasional basis (at least three times weekly), either without or with inhaled corticosteroids, for control of their asthma symptoms. For the combined studies, 48% (52/109) patients randomized to placebo and 41% (46/113) patients randomized to Azmacort (triamcinolone acetonide (inhalation aerosol)) Inhalation Aerosol treatment were previously treated with inhaled corticosteroids.
Results of weekly lung function tests (FEV1) from one of these trials is presented graphically below. Results of the second study are presented in tabular form as the changes in asthma measures from baseline to the end of the treatment period.
Mean Changes in Asthma Measures from Baseline to Endpointa
All-Treated Patients Results from a Placebo-Controlled, 6 Week Study
|Asthma Measure|| Placebo
| Azmacort 300 mcg bid
|Percent Change in FEV1(%)||2.8%||17.5%|
|Increase in Morning Peak||6.7||45.9|
|Flow Rate (L/min)|
|Decrease in Albuterol Use||0.6||3.4|
|Decrease in Daily Asthma Symptom Score (units/day)b||0.5||2.3|
| aEndpoint results are obtained from the last evaluable
data, regardless of whether the patient completed 6 weeks of treatment
bScale (0-6) with 0 = no symptom: Maximum Score (AM + PM) =12
In both studies, treatment with Azmacort (triamcinolone acetonide (inhalation aerosol)) Inhalation Aerosol (300 mcg twice daily) resulted in significant improvements in all clinical asthma measures (lung functions, asthma symptoms, use of as-needed beta2-agonist medications) when compared to placebo.
Last reviewed on RxList: 3/25/2008
This monograph has been modified to include the generic and brand name in many instances.
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