Levocitrazine should be used with caution or avoid taking with anti-seizure drugs e.g. carbamazipine anti-anxirty drugs like alprazolam,diazepam, zolpidem, and muscle relaxants, narcotic pain relievers e.g. codeine psychaitric medicines e.g. chlorpromazine, risperidone, amitriptylene, trazodone

Cytochrome P450 enzyme inducer such as phenobarbital may decrease AUC of montelukast up to 40% Other cyctochrome P450 inducers such as rifampin or valproate may also induce the metabolism of montelukast, but clinical effects of these drugs are not well established

Prophylaxis and chronic treatment of asthma in allergic symptoms in allergic rhinitis, watery eyes, runny nose, itching eyes/nose, sneezing, rash, and itching

Drowsiness, tiredness and dry mouth may occur with levocitrazine Most comon adverse effects of montelikast is headdache. A small percentage of rash, dyspepsia, dizziness, and abdominal pain was also noticed with montelukast.

Hypersensitivity to levocitrazine and montelukast Patients should be cautioned against motor coordination such as operating machinery or driving motor vehicle.

CNS depressants and alcohol should be avoided after concurrent use of levocitrazine because additional reduction oin alertness and additional oimpairment of CNS performance may ocur.

Caution should be taken to use montelukast in pregnancy and lactation

Prophylaxis and chronic treatment of asthma in allergic symptoms in allergic rhinitis, watery eyes, runny nose, itching eyes/nose, sneezing, rash, and itching

Recommended dose- Each tablet containing levocitrazine 5mg + monotelukast 10mg to be taken once-daily

Patients should be cautioned against motor coordination such as operating machinery or driving motor vehicle.

Avoid concurrent use of CNS depressants and alcohol.

Concurrent use of levocitrazine should be avoided because additional reduction in alertness and additional oimpairment of CNS performance may ocur.

Pharmacology-

Levocetrizine is a third-generation, non-sedative anti-histamine. It is an orally active and selective H1 receptor antagonist Montelukast is a leukoctriene antagonist and inhibitor of leukotriene biosynthesis.

Montelukast sodium is used for prophylaxis and chronic treatment of asthma and for treatment of allergic rhinitis

Pharmacokinetics-

Levocetrizine gets absorbed rapidly and extrensively from oral route and shows onset of action within 1 hour and provides significant peripheral antihistamine activity for 28 hours after a single dose. Peak plasma concentration is reached in 1.2 +/- 2 hours. The terminal elimination half-life is 5.7+/- 0.2 hours

Montelukast gets rapidly absorbed after oral administration. It takes about 2 to 4 hours to reach peak levels. Bioavailability is approximately 64% and is 10% protein bound. The mean plasma half-life of the drug is 2.7 to 5.5 hours. Monteleukast undergoes extensive metabolism in the liver by cytochrome P450 enzyme system and gets excreted in the bile.

Rationale for the combination- Anti-allergic medicines can cause adverse events such as somnolence and can have additional negative impact on quality of life. Combination therapy of montelukast with levocetrizine gives additional benefits in comparision with monotherapy and siutable for patients

Combination of cetrizine or its enanitomer or salt with one or more leukotriene inhibitors provides synergistic effect for the treatment and prevention of inflammation, asthma or allergic disorder

Combination also avoids or reduces certain side efects assiciated with H1 histamine receptor antagonsists

Caution should be taken to use montelukast in pregnancy and lactation