Background Antihistamines are widely prescribed to children but should be used with caution in young children. Objective To determine the paediatric prescribing pattern of antihistamines with a focus on the off-label prescribing and factors that influence such prescribing. Setting Paediatric wards of a tertiary care hospital setting in Malaysia. Methods The pharmacy-based computer system and medical records were used to collect the required data. Labelling status of each antihistamine was determined based on the information provided in the product leaflets. Main outcome measure Antihistamines prescribed off-label and factors associated with such prescribing. Results Of the 176 hospitalised children aged <18 years prescribed with an antihistamine in the year 2012, 60.8 % received it in an off-label manner. Of 292 antihistamine prescription items, 55.5 % were prescribed off-label. Loratadine (35.3 %) was the most frequently prescribed antihistamine and chlorpheniramine maleate (34.0 %) was the most common antihistamine prescribed off-label. The main reason for the off-label prescribing of antihistamines was prescribing at higher than the recommended dose (30.2 %). Binary logistic regression showed that children aged <2 years (OR 12.65; 95 % CI 2.87-55.67) and the number of medications received (OR 1.14; 95 % CI 1.00-1.29) were significant predictors for the off-label prescribing of antihistamines. Conclusion Prescribing antihistamines for children in an off-label manner was prevalent at the studied locations and warrants further investigation on the consequences of such prescribing.
Phyllanthus amarus Schum. & Thonn. (Phyllanthaceae) is a medicinal plant that is commonly used to treat diseases such as asthma, diabetes, and anemia. This study aimed to examine the antiallergic activity of P. amarus extract and its compounds. The antiallergic activity was determined by measuring the concentration of allergy markers release from rat basophilic leukemia (RBL-2H3) cells with ketotifen fumarate as the positive control. As a result, P. amarus did not stabilize mast cell degranulation but exhibited antihistamine activity. The antihistamine activity was evaluated by conducting a competition radioligand binding assay on the histamine 1 receptor (H1R). Four compounds were identified from the high performance liquid chromatography (HPLC) analysis which were phyllanthin (1), hypophyllanthin (2), niranthin (3), and corilagin (4). To gain insights into the binding interactions of the most active compound hypophyllanthin (2), molecular docking was conducted and found that hypophyllanthin (2) exhibited favorable binding in the H1R binding site. In conclusion, P. amarus and hypophyllanthin (2) could potentially exhibit antiallergic activity by preventing the activation of the H1 receptor.