DiffCof Chesty Cough Syrup Mechanism of Action

Pharmacology: Pharmacodynamics: Mechanism of Action: Bromhexine is synthetic derivative of the herbal active ingredient vasicine.
Preclinically, it has been shown to increase the proportion of serous bronchial secretion. Bromhexine enhances mucus transport by reducing mucus viscosity and by activating the ciliated epithelium (mucociliary clearance).
In clinical studies, Bromhexine showed a secretolytic and secretomotor effect in the bronchial tract area, which facilitates expectoration and eases cough.
Following the administration of bromhexine, the antibiotic concentrations of amoxycillin, erythromycin and oxytetracycline in the sputum and bronchopulmonary secretions are increased.
Pharmacokinetics: Absorption: Bromhexine is rapidly and completely absorbed from the gastrointestinal tract.
After oral administration solid and liquid formulations show similar bioavailability.
The absolute bioavailability of bromhexine hydrochloride was about 22.2 ± 8.5% and 26.8 ± 13.1% for tablets and solution, respectively. The first-pass metabolism amounts to about 75-80%. Concomitant food intake tended to increase bromhexine plasma concentrations probably due to partial inhibition of the first-pass effect.
Distribution: After intravenous administration bromhexine was rapidly and widely distributed throughout the body with a mean volume of distribution (V_ss) of up to 1209 ± 206 L (19 L/kg). The distribution into lung tissue (bronchial and parenchymal) was investigated after oral administration of 32 mg and 64 mg bromhexine. Lung-tissue concentrations two hours post dose 1.5-4.5 times higher in bronchiolo-bronchial tissues and between 2.4-5.9 times higher in pulmonary parenchyma compared to plasma concentrations.
Unchanged bromhexine is bound to plasma proteins by 95% (non-restrictive binding).
Metabolism: Bromhexine is extensively metabolised to a variety of hydroxylated metabolites and to dibromoanthranilic acid. All metabolites and bromhexine itself are conjugated most probably in form of N-glucuronides and O-glucuronides. There are no substantial hints for a change of the metabolic pattern by a sulphonamide, oxytetracycline or erythromycin. Thus relevant interactions with CYP 450 2C9 or 3A4 substrates are unlikely.
Elimination: Bromhexine is a high extraction ratio drug after i.v. administration in the range of the hepatic blood flow, 843-1073 mL/min resulting in high inter- and intra-individual variability (CV >30%). After administration of radiolabelled bromhexine about 97.4 ± 1.9% of the dose were recovered as radioactivity in urine, with less than 1% as parent compound. Bromhexine plasma concentrations showed a multiexponential decline. After administration of single oral doses between 8 and 32 mg, the terminal elimination half-life ranged between 6.6 and 31.4 hours. The relevant half-life to predict the multiple dose pharmacokinetics is about 1 hour, thus no accumulation was seen after multiple dosing (accumulation factor 1.1).
Linearity/Non-Linearity: Bromhexine shows dose proportional pharmacokinetics in the range of 8-32 mg following oral administration.
Kinetics in Special Populations: There are no data for bromhexine pharmacokinetics in the elderly or in patients with renal or liver insufficiency. Extensive clinical experience did not give rise to relevant safety concerns in these populations.