Montelukast sodium is a selective and orally active leukotriene receptor antagonist that inhibits the cysteinyl leukotriene (CysLT1), receptor demonstrated by the ability to inhibit bronchoconstriction due to inhaled LTD4 in asthmatics. Doses as low as 5 mg cause substantial blockage of LTD4 -induced bronchoconstriction
Levocetirizine is the R-enantiomer of cetirizine. Levocetirizine is an orally active, potent, selective and long acting H1-histamine receptor antagonist with no anticholinergic activity. Used to relieve the symptoms of hay fever and hives of the skin. It works by preventing the effects of a substance called histamine, which is produced by the body. Histamine can cause itching, sneezing, runny nose, and watery eyes. It can close up the bronchial tubes (air passages of the lungs) and make breathing difficult.
A combination therapy of montelukast with antihistamines could provide enhancing and complementary effects, thereby reducing both the daytime and night time symptoms effectively. Combination of levocetirizine with montelukast has shown a significant improvement in patients with allergic rhinitis & significant improvement in both daytime and nighttime symptoms in patients on combination therapy as compared and giving both the drugs as monotherapy.
• 12 years or older: 5 mg orally once daily in the evening
• 6 to 11 years old: 2.5 mg orally once daily in the evening
• 2 to 5 years old: 1.25 mg orally once daily in the evening
Indicated for relief of symptoms of allergic rhinitis [seasonal or perennial], as prophylaxis in seasonal allergic rhinitis and treatment of co morbid asthma and allergic rhinitis in patients 15 years of age and over
Many people using this medication do not have serious side effects.Tell your doctor immediately if any of these rare but serious side effects occur: mental/mood changes (such as agitation, aggression, anxiety, trouble sleeping, abnormal dreams, sleep-walking, memory/attention problems, depression, hallucinations, thoughts of harming yourself/suicide), numbness/tingling/shooting pain in the arms or legs, sinus pain/swelling, muscle weakness. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling, severe dizziness, trouble breathing.
In drug-interaction studies, the recommended clinical dose of montelukast did not have clinically important effects on the pharmacokinetics of the following drugs: theophylline, prednisone, rednisolone, oral contraceptives, terfenadine, digoxin, and warfarin.
Montelukast was used concomitantly with a wide range of commonly prescribed drugs in clinical studies without evidence of clinical adverse interactions. These medications included thyroid hormones, sedative hypnotics, 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.
In vitro data indicate that levocetrizine is unlikely to produce pharmacokinetic interactions through inhibition or induction of liver drug-metabolizing enzymes. Drug interaction studies have been performed with racemic cetrizine.Pharmacokinetic interaction studies performed with racemic cetrizine demonstrated that cetrizine did not interact with antipyrine, pseudoephedrine, erythromycin, azithromycin, ketoconazole and cimetidine. There was a small decrease (~16%) in the clearance of cetrizine caused by a 400 mg dose of theophylline. It is possible that higher theophylline doses could have a greater effect. Ritonavir increased the plasma AUC of cetrizine by about 42% accompanied by an increase in half-life (53%) and a decrease in clearance (29%) of cetrizine. The disposition of ritonavir was not altered by concomitant cetrizine administration.