1. Clinical Overview
A fixed-dose combination of a methylxanthine bronchodilator (Doxofylline) and a mucolytic/expectorant agent (Ambroxol). Doxofylline is a selective phosphodiesterase-4 (PDE-4) inhibitor with bronchodilatory and anti-inflammatory properties, offering a better safety profile than theophylline. Ambroxol is a metabolite of bromhexine that enhances mucus clearance by increasing serous secretion, stimulating surfactant production, and activating the ciliary transport system. This combination is widely used in India for the management of obstructive airway diseases with productive cough.
| Onset | Duration | Bioavailability |
|---|---|---|
| Doxofylline: 30-60 minutes. Ambroxol: 30 minutes. | Doxofylline: Approximately 12 hours. Ambroxol: 6-12 hours. | Doxofylline: ~62-75%. Ambroxol: ~70-80%. |
2. Mechanism of Action
Doxofylline selectively inhibits phosphodiesterase-4 (PDE-4), increasing intracellular cAMP in bronchial smooth muscle and inflammatory cells, leading to bronchodilation and anti-inflammatory effects. Ambroxol is a mucoactive agent that breaks down acid mucopolysaccharide fibers in sputum, reduces viscosity, and stimulates type II pneumocytes to produce surfactant. It also has antioxidant and local anesthetic properties on airways.
3. Indications & Uses
- Bronchial Asthma (maintenance therapy)
- Chronic Obstructive Pulmonary Disease (COPD) including chronic bronchitis and emphysema
4. Dosage & Administration
Adult Dosage: One tablet (Doxofylline 200mg + Ambroxol 30mg) twice daily, preferably after meals. Maximum: Two tablets per day.
Administration: Swallow the tablet whole with a full glass of water, after food to minimize gastric irritation. Do not crush or chew. Maintain adequate hydration to aid mucolytic action of Ambroxol.
5. Side Effects
Common side effects may include:
- Nausea
- Epigastric discomfort/Heartburn
- Headache
- Mild dizziness
- Diarrhea
6. Drug Interactions
| Drug | Effect | Severity |
|---|---|---|
| Ciprofloxacin/Enoxacin | Increased Doxofylline levels (CYP1A2 inhibition), risk of toxicity | Major |
| Phenobarbital/Carbamazepine/Phenytoin | Decreased Doxofylline levels (enzyme induction), reduced efficacy | Moderate |
| Beta-2 Agonists (Salbutamol, Terbutaline) | Additive risk of hypokalemia and tachycardia | Moderate |
| Theophylline | Additive toxicity; concurrent use not recommended | Major |
| Warfarin | Ambroxol may potentiate anticoagulant effect; monitor INR | Moderate |
| Antitussives (Codeine, Dextromethorphan) | Counteracts expectorant action of Ambroxol; avoid combination | Moderate |
7. Patient Counselling
- DO take the tablet after meals with plenty of water.
- DO report any irregular heartbeat, severe headache, or persistent nausea.
- DO maintain good hydration to help loosen mucus.
- DO inform your doctor about all other medicines you are taking.
- DONT crush, break, or chew the tablet.
- DONT take with other cough suppressants (like codeine).
- DONT exceed the prescribed dose.
- DONT stop taking abruptly if used for chronic conditions like asthma.
8. Toxicology & Storage
Overdose: Primarily due to Doxofylline: Severe nausea/vomiting, hematemesis, tremors, agitation, tachycardia, cardiac arrhythmias (supraventricular/ventricular), hypotension, seizures, metabolic acidosis. Ambroxol: Nausea, vomiting, diarrhea, hypersalivation.
Storage: Store below 30°C, in a cool, dry place, protected from light and moisture. Keep out of reach of children.