Asthadox M

Asthadox M Uses, Dosage, Side Effects, Food Interaction and all others data.

Doxophylline is a novel bronchodilator. It structurally differs from Theophylline due to the presence of a dioxolane group in position 7.

Doxophylline selectively inhibits phosphodiesterase 4 thereby relaxes bronchial smooth muscle. However, differently from Theophylline, Doxophylline appears to have decreased affinities toward adenosine A1 and A2 receptors, which may account for the better safety profile of the drug. Doxophylline is reported to inhibit platelet activating factor (PAF) and generation of leukotriene production.

Doxofylline is a methylxanthine bronchodilator with potent bronchodilator activity comparable to that of theophylline. In animal studies, doxofylline demonstrated to attenuate bronchoconstriction, inflammatory actions and the release of thromboxane A2 (TXA2) when challenged with platelet-activating factor .

Doxofylline does not demonstrate direct inhibition of any histone deacetylase (HDAC) enzymes or known PDE enzyme isoforms and did not act as an antagonist at A2 or A2 receptors. The affinity for adenosine A1, A2A and A2B receptors are reported to be all higher than 100 µM . It only displays an inhibitory action against PDE2A1 and antagonism at adenosine A(2A) at high concentrations [A31642]. A study demonstrated that doxofylline interacts with β2-adrenoceptors to induce blood vessel relaxation and airway smooth muscle relaxation. In dog studies, doxofylline decreased airway responsiveness at a dose that did not affect heart rate and respiratory rate .

Montelukast is a selective leukotriene receptor antagonist that inhibits the effects of cysteinyl leukotrienes in the airways. Cysteinyl leukotrienes and leukotriene receptor occupation have been correlated with the pathophysiology of asthma, including airway oedema, smooth muscle contraction, and altered cellular activity associated with the inflammatory process, which contribute to the signs and symptoms of asthma.

Montelukast is a leukotriene receptor antagonist that demonstrates a marked affinity and selectivity to the cysteinyl leukotriene receptor type-1 in preference to many other crucial airway receptors like the prostanoid, cholinergic, or beta-adrenergic receptors. As a consequence, the agent can elicit substantial blockage of LTD4 leukotriene-mediated bronchoconstriction with doses as low as 5 mg. Moreover, a placebo-controlled, crossover study (n=12) demonstrated that montelukast is capable of inhibiting early and late phase bronchoconstriction caused by antigen challenge by 75% and 57% respectively.

In particular, it has been documented that montelukast can cause bronchodilation as soon as within 2 hours of oral administration. This action can also be additive to the bronchodilation caused by the concomitant use of a beta agonist. Nevertheless, clinical investigations performed with adults 15 years of age and older revealed that no additional clinical benefit is obtained when doses of montelukast greater than 10 mg a day are used.

Additionally, in clinical trials with adults and pediatric asthmatic patients aged 6 to 14 years, it was also determined that montelukast can reduce mean peripheral blood eosinophils by about 13% to 15% from baseline in comparison to placebo during double-blind treatment periods. At the same time, in patients aged 15 years and older who were experiencing seasonal allergic rhinitis, the use of montelukast caused a median reduction of 13% in peripheral blood eosinophil counts when compared to placebo as well.

Asthadox M
Uses
Dosage
Side Effect
Precautions
Interactions
Uses during Pregnancy
Uses during Breastfeeding
Accute Overdose
Food Interaction
Half Life
Volume of Distribution
Clearance
Interaction With other Medicine
Contradiction
Storage

Trade Name	Asthadox M
Generic	Doxofylline + Montelukast
Type	Tablet
Therapeutic Class
Manufacturer	Colgen Pharma
Available Country	India
Last Updated:	September 19, 2023 at 7:00 am

Uses

Doxophylline is used to treat asthma, COPD and bronchospasm.

Montelukast is used for-

The prophylaxis and chronic treatment of asthma in adults and paediatric patients 12 months of age and older.
The relief of symptoms of seasonal allergic rhinitis in adults and paediatric patients 2 years of age and older.

Asthadox M is also used to associated treatment for these conditions: Bronchial Asthma, Chronic Obstructive Pulmonary Disease (COPD), Pulmonary DiseasesAsthma, Exercise-Induced Bronchospasm, Perennial Allergic Rhinitis (PAR), Seasonal Allergic Rhinitis

How Asthadox M works

The main mechanism of action of doxofylline is unclear. One of the mechanisms of action of is thought to arise from the inhibition of phosphodiesterase activity thus increasing the levels of cAMP and promoting smooth muscle relaxation.

The interaction of doxofylline with beta-2 adrenoceptors was demonstrated by a study using nonlinear chromatography, frontal analysis and molecular docking [A31646]. Serine 169 and serine 173 residues in the receptor are thought to be critical binding sites for doxofylline where hydrogen bonds are formed [A31646]. Via mediating the actions of beta-2 adrenoceptors, doxofylline induces blood vessel relaxation and airway smooth muscle relaxation.

There is also evidence that doxofylline may exert anti-inflammatory actions by reducing the pleurisy induced by the inflammatory mediator platelet activating factor (PAF) according to a rat study [A31646]. It is suggested that doxofylline may play an important role in attenuating leukocyte diapedesis, supported by mouse preclinical studies where doxofylline administration was associated with inhibited leukocyte migration across vascular endothelial cells in vivo and in vitro .Unlike theophylline, doxofylline does not inhibit tumor necrosis factor-induced interleukin (IL)-8 secretion in ASM cells.

Cysteinyl leukotrienes (CysLT) like LTC4, LTD4, and LTE4, among others, are eicosanoids released by a variety of cells like mast cells and eosinophils. When such CysLT bind to corresponding CysLT receptors like CysLT type-1 receptors located on respiratory airway smooth muscle cells, airway macrophages, and on various pro-inflammatory cells like eosinophils and some specific myeloid stem cells activities that facilitate the pathophysiology of asthma and allergic rhinitis are stimulated.

In particular, CysLT-mediated airway bronchoconstriction, occluding mucous secretion, vascular permeability, and eosinophil recruitment are all types of effects that facilitate asthma. Alternatively, in allergic rhinitis, CysLTs are released by the nasal mucosa when exposed to allergens during both early and late phase reactions and participate in eliciting symptoms of allergic rhinitis like a congested nose and airway.

Subsequently, montelukast is a leukotriene receptor antagonist that binds with high affinity and selectivity to the CysLT type 1 receptor, which consequently assists in inhibiting any physiological actions of CysLTs like LTC4, LTD4, and LTE4 at the receptor that may facilitate asthma or allergic rhinitis.

Dosage

Asthadox M dosage

Adult:400 mg daily in the evening. However, in certain cases, 400 mg twice daily is recommended on the basis of the clinical response. Doses as high as 1200 mg/day (400 mg 3 times daily) may also be prescribed. In elderly patients with concomitant cardiovascular, hepatic and renal diseases recommended dosage should be 200 mg twice daily.

Children (above 6 years of age):The recommended dosage of Doxophylline is 6 mg/kg twice daily. The dose may be increased up to 18 mg/kg daily on the basis of clinical response.

Dosage Type: 6 mg/kg b.i.d

Weight of the Child: 10 kg > Dosage: 3 ml
Weight of the Child: 15 kg > Dosage: 4.5 ml
Weight of the Child: 20 kg > Dosage: 6 ml
Weight of the Child: 25 kg > Dosage: 7.5 ml
Weight of the Child: 30 kg > Dosage: 9 ml
Weight of the Child: 35 kg > Dosage: 10.5 ml
Weight of the Child: 40 kg > Dosage: 12 ml

General information: Montelukast should be taken once daily. For asthma, the dose should be taken in the evening. For seasonal allergic rhinitis, the time of administration may be individualised to suit patients needs. Patients with both asthma and seasonal allergic rhinitis should take only one tablet daily in the evening.

Adults and adolescents 15 years of age and older with asthma or seasonal allergic rhinitis: The dosage is one 10 mg tablet daily.

Paediatric patients 6 to 14 years of age with asthma or seasonal allergic rhinitis: The dosage is one 5 mg tablet daily. No dosage adjustment within this age group is necessary.

Paediatric patients 2 to 5 years of age with asthma or seasonal allergic rhinitis: The dosage is one 4 mg tablet daily.

Paediatric patients 12 to 23 months of age with asthma: The dosage is one 4 mg tablet daily to be taken in the evening. Safety and effectiveness in paediatric patients younger than 12 months of age have not been established.

Side Effects

Patients treated with Xanthine derivatives may suffer nausea, vomiting, epigastric pain, headache, irritability, insomnia, tachycardia, extrasystoles, tachypnea, and in rare cases, hyperglycemia or albuminuria.

Adolescents and Adults 15 years of age and older: In placebo-controlled clinical trials, Montelukast has been evaluated for safety in approximately 2600 adolescent and adult patients of 15 years and older, the following adverse experiences reported with Montelukast occurred in greater than or equal to 1% of patients.

General: Asthenia/fatigue, Fever, Pain
Gastrointestinal: Dyspepsia, Gastroenteritis; Nervous
System/Psychiatric: Dizziness, Headache
Respiratory System: Congestion, Cough, Influenza
Skin: Rash; Laboratory adverse experiences: ALT increase, AST increase, Pyuria.

Paediatric patients 6 to 14 years of age: In paediatric patients receiving montelukast, the following events occurred with a frequency 2% are diarrhoea, laryngitis, pharyngitis, nausea, otitis, sinusitis, and viral infection. With prolonged treatment, the adverse profile did not change significantly.

Toxicity

Oral LD50 in rat and mouse are 965 mg/kg and 841 mg/kg, respectively. Intraperitoneal LD50 in rat and mouse are 426 mg/kg and 396 mg/kg, respectively .

The adverse effects associated with overdosage of montelukast include abdominal pain, somnolence, thirst, headache, vomiting, psychomotor hyperactivity, and less frequently, convulsion.

The oral LD50 value determined for mice and rats is >5000 mg/kg.

Montelukast has not been studied in pregnant women. Consequently, it should be used during pregnancy only if clearly needed.

Additionally, as it is unknown whether montelukast is excreted into human breast milk, there is also caution regarding the use of the medication in nursing mothers.

The plasma half-life of montelukast is somewhat prolonged in elderly patients, although no dosage adjustment is generally necessary.

Precaution

Use with caution in patients with hypoxemia, hyperthyroidism, liver disease, renal disease, in those with history of peptic ulcer and in elderly. Frequently, patients with Congestive Heart Failure (CHF) have markedly prolonged drug serum levels following discontinuation of Doxofylline.

Montelukast is not indicated for use in the reversal of bronchospasm in acute asthma attacks (in case of status asthmaticus). Patients with known aspirin sensitivity should continue avoidance of aspirin or other NSAID, while taking Montelukast.

In rare cases, patients on therapy with Montelukast may present with systemic eosinophilia, sometimes presenting with clinical features of vasculitis consistent with churg-strauss syndrome, a condition which is often treated with systemic corticosteroid therapy. Physician should be alert to eosinophilia, vasculitic rash, worsening pulmonary symptoms, cardiac complications, and/or neuropathy presenting in their patients. A causal association between Montelukast and these underlying conditions has not been established.

Interaction

Doxophylline should not be administered together with other xanthine derivatives. Toxic synergism with ephedrine has been documented for xanthines. Like other xanthines, concomitant therapy with erythromycin, troleandomycin, lincomycin, allopurinol, cimetidine, ranitidine, propranolol and anti-flu vaccine may decrease the hepatic clearance of xanthines causing an increase in blood levels.

Montelukast has been administered with other therapies routinely used in the prophylaxis and chronic treatment of asthma with no apparent increase in adverse reactions. In drug interaction studies, the recommended clinical dose of montelukast did not have clinically important effects on the pharmacokinetics of the following drugs: Theophylline, Prednisolone, oral contraceptives (Norethindrone 1 mg/Ethinyl Oestradiol 35 mg), Terfenadine, Digoxin, and Warfarin.

Although additional specific interaction studies were not performed, Montelukast was used concomitantly with a wide range of commonly prescribed drugs in clinical studies without clinically evident adverse interactions. These medications included thyroid hormones, sedative hypnotic, non-steroidal anti-inflammatory agents, benzodiazepines, and decongestants.

Phenobarbital, which induces hepatic metabolism, decreased the AUC of Montelukast approximately 40% following a single 10 mg dose of Montelukast. No dosage adjustment for Montelukast is recommended. It is reasonable to employ appropriate clinical monitoring when potent cytochrome P450 enzyme inducers, such as Phenobarbital or Rifampin, are co-administered with Montelukast.

Volume of Distribution

Doxofylline demonstrates a short distribution phase following intravenous administration of 100 mg given in adults with chronic bronchitis . As methylxanthines are distributed to all body compartments, doxofylline may be detected in breast milk and placenta .

The steady-state volume of distribution recorded for montelukast is an average between 8 to 11 litres.

Elimination Route

After repeated administrations doxofylline reaches the steady-state in about 4 days. Following oral administration of 400 mg doxofylline twice daily for 5 days in adults with chronic bronchitis, the peak plasma concentrations (Cmax) at steady state ranged from 5.78 to 20.76 mcg/mL. The time to reach maximum concentration (Tmax) was 1.19 ± 0.19 hours . The absolute bioavailability of doxofylline in healthy subjects was 63 ± 25% .

It has been observed that montelukast is quickly absorbed following administration by the oral route. The oral bioavailability documented for the drug is 64%. Furthermore, it seems that having a regular meal in the morning or even a high fat snack in the evening does not affect the absorption of montelukast.

Half Life

Following administration of a single intravenous dose of 100 mg over 10 minutes in adults with chronic bronchitis, the elimination half life of doxofylline was 1.83 ± 0.37 hours. Following oral administration of 400 mg twice daily for 5 days in adults with chronic bronchitis, the mean elimination half life was 7.01 ± 0.80 hours .

Studies have demonstrated that the mean plasma half-life of montelukast varies from 2.7 to 5.5 hours when observed in healthy young adults.

Clearance

Following oral administration of 400 mg doxofylline twice daily for 5 days, the total clearance was 555.2 ± 180.6 mL/min .

The plasma clearance documented for montelukast is an average of 45 mL/min when observed in healthy adults.

Elimination Route

Less than 4% of an orally administered dose is excreted unchanged in the urine due to extensive hepatic metabolism .

It has been reported that montelukast and its metabolites are almost exclusively excreted in the bile and into the feces.

Pregnancy & Breastfeeding use

Use in pregnancy: Animal reproduction studies indicate that Doxophylline does not cause fetal harm when administered to pregnant animals nor can affect reproduction capacity. However, since there is limited experience in human during pregnancy, Doxophylline should be given to pregnant women only if clearly needed.

Use in nursing mothers: Doxophylline is contraindicated in nursing mothers.

Pregnancy: Montelukast crosses the placenta following oral dosing in rats and rabbits. There are, however, no adequate and well controlled studies in pregnant women. Because animal reproduction studies are not always predictive of human response, Montelukast should be used during pregnancy only if clearly needed.

Lactation: It is not known if Montelukast is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when Montelukast is given to a nursing mother.

Contraindication

This is contraindicated for individuals who have shown hypersensitivity to Doxofylline and its components. It is also contraindicated in patients with acute myocardial infarction, hypotension, and in lactating women.

Montelukast is contraindicated to patients with hypersensitivity to any component of this product.

Special Warning

Paediatric use: Safety and efficacy of Montelukast has been established in adequate and well controlled studies in paediatric patients with asthma and allergic rhinitis between age 1 to 14 years. Long term trials evaluatingthe effect of chronic administration of Montelukast on linear growth in paediatric patients have not been conducted.

Geriatric use: Of the total number of subjects in clinical studies of Montelukast, 3.5% were 65 years of age and over and 0.4% were 75 years of age and over. No overall differences in safety or effectiveness were observed between these subjects and younger subjects. But greater sensitivity of some older individuals cannot be ruled out.

Acute Overdose

In case of overdose severe cardiac arrhythmias and tonic-clonic seizure may occur. These effects may represent the first signs of intoxication. The appearance of side effects may require discontinuation of the treatment which, if necessary, at the physician’s discretion, may be resumed at lower doses after all signs and symptoms of toxicity have subsided.

As there is no specific antidote, in case of overdose a symptomatic treatment of cardiovascular collapse should be instituted.

Symptoms: Abdominal pain, somnolence, thirst, headache, vomiting, and psychomotor hyperactivity.

Management: Supportive and symptomatic treatment. If indicated, unabsorbed material should be removed from the GI tract.