M Fex

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

Fexofenadine Hydrochloride is an antihistamine with selective peripheral H1 receptor antagonist activity. It inhibits histamine release from peritoneal mast cells. No anticholinergic, α-1 adrenergic or β-adrenergic receptor blocking effects has been observed. No sedative or other central nervous system effect has been observed. It does not appear to cross the blood brain barrier.

Fexofenadine is rapidly absorbed after oral administration with peak plasma concentration being reached in 2-3 hours. Elimination half-life of about 14 hours has been reported although this may be prolonged in patients with renal impairment.

Fexofenadine relieves allergy symptoms by antagonizing the actions of histamine, an endogenous compound predominantly responsible for allergic symptomatology. The relatively long duration of action of fexofenadine (approximately 24 hours) allows for once or twice daily dosing, and its rapid absorption allows for an onset of action within 1-3 hours. Fexofenadine should not be taken with fruit juice, as this may impair its absorption.

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.

M Fex
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	M Fex
Generic	Montelukast + Fexofenadine
Weight	10mg, 120mg
Type	Tablet
Therapeutic Class
Manufacturer	Seagull Pharmaceutical Pvt Ltd
Available Country	India
Last Updated:	September 19, 2023 at 7:00 am

Uses

It is used for the relief of symptoms associated with seasonal and perennial allergic rhinitis and chronic idiopathic urticaria.

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.

M Fex is also used to associated treatment for these conditions: Allergic Rhinitis (AR), Chronic Idiopathic Urticaria, Seasonal Allergic Rhinitis, AntihistamineAsthma, Exercise-Induced Bronchospasm, Perennial Allergic Rhinitis (PAR), Seasonal Allergic Rhinitis

How M Fex works

The H₁ histamine receptor is responsible for mediating hypersensitivity and allergic reactions. Exposure to an allergen results in degranulation of mast cells and basophils, which then release histamine and other inflammatory mediators. Histamine binds to, and activates, H₁ receptors, which results in the further release of pro-inflammatory cytokines, such as interleukins, from basophils and mast cells. These downstream effects of histamine binding are responsible for a wide variety of allergic symptoms, such as pruritus, rhinorrhea, and watery eyes.

Fexofenadine is considered an “inverse agonist” of the H₁ receptor because it binds to and stabilizes the inactive form of the receptor, preventing its activation and subsequent downstream effects. It has a potent and selective affinity for H₁ receptors, and there is no evidence that it carries antidopaminergic, antiserotonergic, anticholinergic, sedative, or adrenergic blocking activity. Fexofenadine does not cross the blood-brain barrier and thus is unlikely to cause significant CNS effects.

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

M Fex dosage

Adults-

Allergic rhinitis: 120 mg once daily or 60 mg twice daily
Urticaria: 180 mg once daily

Children-

2-11 years: 30 mg (1 spoonful) or 5 ml twice daily
6 months-2 years: 15 mg (1/2 spoonful) or 2.5 ml twice daily

In case of decreased renal function, care should be taken in dose selection and it may be useful to monitor renal function.

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

Fexofenadine is generally well tolerated. The most commonly reported adverse events are headache, drowsiness, nausea, and dizziness. The incidence of these events observed with Fexofenadine hydrochloride was similar to that observed with placebo.

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

No deaths were observed following the oral administration of up to 5000 mg/kg in both mice and rats (equivalent to approximately 100-200x the recommended human dose). Single doses of up to 800 mg and chronic exposure of up to 690 mg twice daily for 1 month in humans did not result in clinically significant adverse events. Symptoms of overdosage are consistent with fexofenadine's adverse effect profile and are likely to include dizziness, drowsiness, and dry mouth.

If overdosage occurs, employ symptomatic and supportive treatment. Hemodialysis does not effectively remove fexofenadine from the blood and is therefore of no benefit.

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

Studies in the elderly, patients with hepatic impairment and patients with cardiac disease exposed to Fexofenadine showed no statistically significant differences compared to healthy individuals. As with most new drugs there is only limited data in the elderly and renally or hepatically impaired patients. Fexofenadine hydrochloride should be administered with care in these special groups.

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

Co-administration of Fexofenadine Hydrochloride with either ketoconazole or erythromycin may cause increased plasma concentration of Fexofenadine. Antacid containing Aluminium and Magnesium may reduce the absorption of Fexofenadine. Fruit juices such as grapefruit, orange and apple may reduce the bioavailability of Fexofenadine.

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

The volume of distribution is approximately 5.4-5.8 L/kg.

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

Elimination Route

Fexofenadine is rapidly absorbed following oral administration and its absolute bioavailability is approximately 33%. The T_max following oral administration is approximately 1-3 hours. The steady-state AUC_ss(0-12h) and C_max following twice daily dosing of 60mg are 1367 ng/mL.h and 299 ng/mL, respectively.

Fexofenadine AUC is decreased by >20% when coadministered with fruit juices (e.g. apple, orange, grapefruit) due to their inhibition of OATP transporters - for this reason, prescribing information recommends administering fexofenadine only with water. Similarly, coadministration of fexofenadine with a high-fat meal appears to decrease AUC and C_max by >20%.

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

The terminal elimination half-life is approximately 11-15 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

The oral clearance of fexofenadine is approximately 50.6 L/h and the renal clearance is approximately 4.32 L/h.

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

Elimination Route

Approximately 80% of an ingested dose is eliminated in the feces, likely largely unchanged due to fexofenadine's limited metabolism, and 11% is eliminated in the urine. The principal pathways of fexofenadine elimination are biliary and renal.

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

Pregnancy & Breastfeeding use

Pregnancy Category B. There are no adequate and well controlled studies in pregnant women. Fexofenadine should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

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

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

Fexofenadine is contraindicated in patients with known hypersensitivity to Fexofenadine or any of the ingredients of Fexofenadine Hydrochloride.

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

Special Warning

Studies in special risk groups (elderly, renally or hepatically impaired patients) indicate that it is not necessary to adjust the dose of Fexofenadine Hydrochloride in these patients.

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 an overdose, standard measures to remove any unabsorbed drug should be employed. Symptomatic and supportive treatment is recommended. There has been no reported case of an acute overdose of Fexofenadine hydrochloride.

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.