Cetirizine (Film coated tablets 5 , 10 mg )
Each film coated tablet contains: 5 , 10 mg of Cetirizine hydrochloride .
Chemical name: The dihydrochloride of 2-[4-(4-chlorobenzhydryl)piperazin-1-yl]ethoxyacetic acid Molecular formula: C21H25ClN2O3,2HCl =461.8
Mechanism of Action:
Cetirizine , a human metabolite of hydroxyzine , is an antihistamine , its principal effects are mediated via selective inhibition of peripheral (H1) receptors. The antihistaminic ativity of cetirizine has been clearly documented in a variety of animal and human models . In vivo and ex vivo animal models have shown negligible anticholinergic and antiserotonergic activity . In vitro receptor binding studies have shown no measurable affinity for other than H1 receptors .
Absorption : Cetirizine is rapidly absorbed after oral administration peak plasma levels are reached within 1 hour . Food does not affect the extent of absorption but may decrease , the rate . Cetirizine is widely distributed but does not appear to cross the blood-brain barrier to any significant extent .
Protein Binding : The mean plasma protein binding of cetirizine is 93% .
Elimination half life : 8.3 hours .
Elimination : 70% in urine and 10% in feces . Approximately 50% in urine was unchanged .
Allergic Rhinitis (Seasonal or Perennial) : Cetirizine is indicated for the relief of symptoms associated with seasonal or Perennial allergic Rhinitis in adults and children 2 years of age and older. Symptoms treated effectively include sneezing , rhinorrhea, nasal pruritus . ocular pruritus , tearing, and redness of the eyes and duration of hives and significantly reduces pruritus .
Patients with a known hypersensitivity to cetirizine or any of its ingredients or hydroxyzine .
Activities Requiring Mental Alertness : the occurrence of somnolence has been reported in some patients taking Cetirizine ; due caution should therefore be excrcised when driving a car or operating potentially dangerous machinery . Concurrent use of Cetirizine with alcohol or other CNS depressants should be avoided because additional reductions in alertness and additional impairment of CNS performance may occur .
Renal Impairment : Dosing adjustment is necessary in patients with moderate or severe renal impairment and in patients on dialysis .
Hepatic Impairment : Dosing adjustment may be necessary in patients with hepatic impairment .
Category B . There are no adequate and well controlled studies in pregnant women .
Cetirizine should be used in pregnancy only or if clearly needed .
Breast – feeding:
Cetirizine has been reported to be excreted in human breast milk . Use of Cetirizine in nursing mothers in not recommended .
No clinically significant drug interactions have been found with theophylline at a low dose , azithromycin , pseudoephedrine , ketoconazole , or erythromycin . There was a small decrease in the clearance of cetirizine caused by a 400 – mg dose of theophylline ; it is possible that larger theophylline doses could have a greater effect .
Adverse Reactions :
Solmolence, fatigue , drug moufu . In cuildren abdominal pain , pharyngitis diarrhea , Bronchospasm and vomiting was the most common adverse reactions .
Overdose has been reported with Cetirizine . In one adult patient who took 150 mg of Cetirizine , the patient was somnolent but did not display any other clinical signs or abnormal blood chemistry or hematology results . In an 18 month old pediatric patient who took an oversode of Cetirizine (approximately 180 mg) , restlessness and irritability were observed initially ; this was followed by drowsiness .
treatment should be symptomatic or supportive , taking into account any concomitantly ingested medications. There is no known specific antidote to Cetirizine . Cetirizine is not effectively removed by dialysis, and dialysis will be ineffective unless a dialyzable agent has been concomitantly ingested.
Adminisitration and Dosage:
Cetirizine can be taken without regard to food consumptions. Cetirizine is available as 5 to 10 mg tablets .
The recommended initial dose of Cetirizine is 5 mg and 10 mg per day in adults and children 12 years and older , depending on symptom severity . Most patients in clinical trials started at 10 mg . Cetirizine is given as a single daily dose . The time of administration may be varied to suit individual patient needs .
Children 6 to 11 years : The recommended initial dose of Cetirizine in children aged 6 to 11 years is 5 mg or 10 mg once daily depending on symptom severity . The time of administration may be varied to suit individual patient needs.
Children 2 to 5 years : The recommended initial dose of Cetirizine in children aged 2 to 5 years is 2.5 mg ( 1/2 teaspoon ) syrup once daily . The dosage in this age group can be increased to a maximum dose of 5 mg per day given as 1 teaspoon syrup once a day or one 1/2 teaspoon syrup given every 12 hours , or one 5 mg chewable tablet once a day .
Children 6 months to< 2 years : The recommended dose of Cetirizine syrup in children 6 months to 23 months of age is 2.5 mg (1/2 teaspoon) once daily . The dose in children 12 to 23 months of age can be increased to a maximum dose of 5 mg per day , given as 1/2 teaspoon (2.5 mg) every 12 hours . Syrup is recommended for children under the age of 2 years .
Dose adjustment for Renal and Hepatic Impairment : In patients 12 years of age and older with decreased renal function (creatinine clearance 11-31 mL/min) , patients on hemodialysis (creatinine clearance less than 7 mL/min) . and in hepatically impaired patients, a dose of 5 mg once daily is recommended. Similarly , pediatric patients aged 6 to 11 years with impaired renal or hepatic function should use the lower recommended dose . because of the difficulty in reliably administering doses of less than 2.5 mg ( 1/2 teaspoon) of Cetirizine syrup and in the absence of pharmacokinetic and sagety information for cetirizine in children below the age of 6 years with impaired renal or hepatic function , its use in this impaired patient population is not recommended .
Packaging and storage :
There are boxes of 3 (Blister cards of 10) .
Cetirizine tablets are green , film coated , containing 5 mg or 10 mg Cetirizine Hydrochloride .
Store below 30 ◦ C .
[ Electronic Martindale 35]