A fixed-dose combination (FDC) of a methylxanthine bronchodilator (Doxofylline) and a leukotriene receptor antagonist (Montelukast) used for the management of chronic asthma and COPD. Doxofylline provides bronchodilation with a potentially better safety profile regarding CNS and cardiac stimulation compared to theophylline. Montelukast provides anti-inflammatory action by blocking cysteinyl leukotriene receptors, reducing bronchoconstriction and inflammation. This combination offers synergistic action for improved airway control.
Adult: One tablet (Doxofylline 400mg + Montelukast 10mg) once daily, preferably in the evening. For asthma, Montelukast is typically dosed in the evening.
Note: Administer orally with or without food. Tablet should be swallowed whole with a glass of water. Do not crush or chew. For asthma prophylaxis, take regularly even when asymptomatic.
The combination works via two distinct pathways. Doxofylline acts as a bronchodilator primarily through phosphodiesterase (PDE) IV inhibition and adenosine receptor antagonism, leading to increased intracellular cAMP, relaxation of bronchial smooth muscle, and some anti-inflammatory effects. Montelukast is a selective and competitive antagonist of the cysteinyl leukotriene type 1 (CysLT1) receptor, blocking the action of leukotrienes (LTD4) which cause bronchoconstriction, increased vascular permeability, and eosinophil recruitment.
Pregnancy: Category C (Doxofylline) and Category B (Montelukast). Use only if clearly needed and potential benefit justifies potential risk to the fetus. Montelukast is considered safer among the two. Consult physician.
Driving: Caution advised. Dizziness, drowsiness, and blurred vision have been reported, which may impair ability.
| Ciprofloxacin, Enoxacin | Markedly increases Doxofylline levels (CYP1A2 inhibition). Risk of toxicity. | Major |
| Phenobarbital, Carbamazepine, Rifampicin | Decreases Doxofylline levels (CYP450 induction). May reduce efficacy. | Moderate |
| Warfarin | Doxofylline may potentiate anticoagulant effect. Monitor INR. | Moderate |
| Beta-2 Agonists (e.g., Salbutamol) | Additive effect on hypokalemia and tachycardia. | Moderate |
| Gemfibrozil | Increases Montelukast plasma concentration (CYP2C8 inhibition). Clinical significance unclear. | Minor |
| Phenytoin | May decrease Montelukast concentration. | Minor |
Same composition (Doxofylline (400mg) + Montelukast (10mg)), different brands: