1. Clinical Overview
A fixed-dose combination (FDC) of a methylxanthine bronchodilator (Doxofylline) and a mucolytic agent (Ambroxol) used for the management of chronic obstructive pulmonary disease (COPD) and bronchial asthma with associated productive cough. Doxofylline is a selective phosphodiesterase-4 (PDE4) inhibitor with a better safety profile than theophylline, while Ambroxol facilitates expectoration by increasing mucus clearance.
| Onset | Duration | Bioavailability |
|---|---|---|
| Doxofylline: 1-2 hours; Ambroxol: 30-60 minutes. | Doxofylline: Approximately 12 hours; Ambroxol: 6-12 hours. | Doxofylline: ~62.6%; Ambroxol: ~70-80%. |
2. Mechanism of Action
Doxofylline acts as a bronchodilator and anti-inflammatory agent by selectively inhibiting phosphodiesterase-4 (PDE4), leading to increased intracellular cAMP. This relaxes bronchial smooth muscle and inhibits the release of pro-inflammatory mediators. Ambroxol is a mucolytic and expectorant that stimulates surfactant production, depolymerizes acid mucopolysaccharide fibers in sputum, and enhances ciliary beat frequency, facilitating mucus clearance.
3. Indications & Uses
- Chronic Obstructive Pulmonary Disease (COPD) - maintenance therapy
- Bronchial Asthma - for relief of bronchospasm and associated productive cough
4. Dosage & Administration
Adult Dosage: One tablet (Doxofylline 400mg + Ambroxol 30mg) twice daily, preferably after meals.
Administration: Swallow the tablet whole with a glass of water, after food to minimize gastric irritation. Do not crush or chew. Maintain adequate hydration to aid mucolytic action.
5. Side Effects
Common side effects may include:
- Nausea
- Epigastric discomfort/Heartburn
- Headache
- Mild dizziness
- Diarrhea
6. Drug Interactions
| Drug | Effect | Severity |
|---|---|---|
| Ciprofloxacin/Enoxacin | Markedly increases Doxofylline levels (CYP1A2 inhibition), risk of toxicity. | Major |
| Phenobarbital, Phenytoin, Rifampicin | Decreases Doxofylline levels (CYP450 induction), may reduce efficacy. | Moderate |
| Beta-2 Agonists (Salbutamol, Terbutaline) | Additive bronchodilation; may potentiate hypokalemia and tachycardia. | Moderate |
| Diuretics (especially Loop Diuretics) | Increased risk of hypokalemia with Doxofylline. | Moderate |
| Warfarin | Ambroxol may slightly increase bleeding risk; monitor INR. | Minor |
| Antitussives (e.g., Codeine) | Counteracts the expectorant action of Ambroxol; avoid concurrent use. | Moderate |
7. Patient Counselling
- DO take the tablet after meals with a full glass of water.
- DO maintain regular dosing intervals.
- DO inform your doctor about all other medicines you are taking.
- DO keep yourself well-hydrated to help loosen mucus.
- DONT crush, break, or chew the tablet.
- DONT take an extra dose if you miss one. Skip it and take the next scheduled dose.
- DONT start or stop any other medication without consulting your doctor.
- DONT consume excessive caffeine (tea, coffee, cola) while on this medication.
8. Toxicology & Storage
Overdose: Primarily due to Doxofylline: Severe nausea/vomiting, hematemesis, tremors, agitation, tachycardia, arrhythmias, hypotension, seizures, metabolic acidosis. Ambroxol overdose: GI distress, salivation, nausea.
Storage: Store below 30°C, in a cool, dry place, protected from light and moisture. Keep out of reach of children.