& Dosage | Action
Adverse Effect & Precautions | Brands available in Market
Loratadine is rapidly absorbed from the gastrointestinal tract after oral administration, peak plasma concentrations being attained in about one hour. Bioavailability is increased and time to peak plasma concentrations is delayed when administered with food. Loratadine undergoes extensive metabolism. The major metabolite, descarboethoxyloratadine (desloratadine), has potent antihistamine activity. Reported mean elimination half-lives for loratadine and descarboethoxyloratadine are 8.4 and 28 hours respectively. Loratadine is about 98% bound to plasma proteins; descarboethoxyloratadine is less extensively bound. Loratadine and its metabolites have been detected in breast milk, but do not appear to cross the blood-brain barrier to a significant extent. Most of a dose is excreted equally in the urine and faeces, mainly in the form of metabolites.
SEASONAL AND PERENNIAL ALLERGIC RHINITIS, SKIN ALLERGIES INCLUDING ALLERGIC DERMATITIS AND URTICARIA, OCULAR ALLERGY: Adult and Children over 30kg: 10mg once daily. Children under 30kg or 5 yrs: 5mg once daily. In patients with liver failure: Start with 10mg on alternate days.
Binds selectively to peripheral histamine H1 receptors. Also has mast cell stabilising effect. Does not cross blood-brain barrier and has no effect on sleep patterns or REM sleep. Antihistamine action quick onset and long duration.
is metabolised by cytochrome P450 isoenzymes CYP3A4 and CYP2D6.
Therefore concomitant administration of other drugs that inhibit
or are metabolised by these hepatic enzymes may result in changes
in plasma concentrations of either drug and, possibly, adverse
effects. Drugs known to inhibit one or other of these enzymes
include cimetidine, erythromycin, ketoconazole, quinidine,
fluconazole, and fluoxetine.
Ketoconazole also appears to be able to inhibit the metabolism of loratadine and at therapeutic doses, is approximately 3 times more inhibitory than erythromycin. (3) However, the concentrations of ketoconazole required are reported to be much higher than those required to inhibit the metabolism of astemizole or terfenadine.
Cimetidine also appears to have an inhibitory effect on the metabolism of loratadine and all 4 drugs also attenuate the clearance of its active metabolite descarboethoxyloratadine although no clinically significant consequences were observed in these studies.
Effect & Precautions
Fatigue, headache, nausea.
Precaution: Neonates, Infants
Pregnancy: Use with caution.
Breast Feeding: Contraindicated.
Man: May be used in reduced dose.