Inflammation and neurological adverse drugs reactions: a case of long lasting impaired consciousness after oxatomide administration in a patient with gastroenteritis

Oxatomide is a H1-histamine receptor antagonist effective in treatment of allergic rhinitis, urticaria, pruritus dermatitis, eczema dermatitis, bronchial asthma and conjunctivitis. The drug inhibits the secretion of several mediators of inflammation from human basophils and mast cells [1]. Studies in neutrophils have also shown that it inhibits arachidonic acid mobilization, and the synthesis of leukotriene B4 and platelet-activating factor, possibly by reducing the activities of cytosolic phospholipase A2 [1]. Studies in human liver microsomes [2] have shown that oxatomide is mainly metabolized by cytochromes 3A4 (CYP3A4) and 2D6 (CYP2D6), two enzymes encoded by highly polymorphic genes [3,4]Whereas at toxic dosages oxatomide may cause coma and long-lasting impaired consciousness, it is generally well tolerated at therapeutic dosage, although slight drowsiness, similarly to other H1-histamine receptor antagonists, may occur in approximately 50% of the patients [5]. To date only one study reported the occurrence of long-lasting impaired consciousness in paediatric patients at therapeutic oxatomide dosages. No pathogenic causes were described for such an effect [6].A 3 year-old Caucasian male, weighing 13.2 Kg, treated for conjunctivitis with oxatomide (TINSET？ - drops 2.5%) at therapeutic doses (14 mg/day for 2 days) experienced at home abdominal pains, pallor, trouble speaking followed by a serious long-lasting impaired consciousness two days after oxatomide treatment. The parents also reported muscular hypotonia. After 2 days the parents accessed the Emergency Department where the child was immediately admitted. The child had no history of recent trauma, seizures and neurologic diseases and was receiving no other drug treatment. The child was affected by acute gastroenteritis.After admission to the Emergency Department oxatomide was withdrawn. Nonetheless, the patient's state of impaired consciusness persisted with very low response to pain stimulation tests and a