Adults

1 inhalation (50 mcg) twice daily, approximately 12 hours apart. For exercise-induced bronchospasm, 1 inhalation (50 mcg) at least 30 minutes before exercise.

Elderly

No dosage adjustment is generally required for elderly patients.

Renal_impairment

No dosage adjustment is generally required for patients with renal impairment.

Onset

Onset of action typically occurs within 10-20 minutes, with significant bronchodilation achieved within 30 minutes.

Excretion

Excreted primarily in feces (about 60%) and urine (about 25%) as metabolites within 72 hours.

Half life

The elimination half-life is approximately 5.5 hours after inhaled administration, but the clinical effect lasts longer.

Absorption

Minimal systemic absorption after inhalation, primarily acts locally in the lungs. Bioavailability is low due to extensive first-pass metabolism.

Metabolism

Extensively metabolized by hydroxylation, primarily by cytochrome P450 3A4 (CYP3A4) enzyme, to inactive metabolites.

Beta-blockers

May block the pulmonary effect of Seroxyn and produce severe bronchospasm in patients with asthma. Should generally be avoided.

MAOIs and TCAs

Monoamine Oxidase Inhibitors (MAOIs) and Tricyclic Antidepressants (TCAs) may potentiate the vascular effects of Seroxyn, leading to severe adverse cardiovascular effects. Use with extreme caution.

Other Sympathomimetics

Concomitant use with other sympathomimetic agents may potentiate adverse cardiovascular effects. Use with caution.

Strong CYP3A4 Inhibitors

Ketoconazole, ritonavir, atazanavir, clarithromycin, indinavir, itraconazole, nefazodone, nelfinavir, saquinavir, telithromycin may increase systemic exposure to Seroxyn, potentially leading to increased cardiovascular adverse effects (e.g., QTc prolongation).