In clinical studies, the most frequently reported adverse events associated with Clarinase 24 Hr Extended Release were headache and dry mouth. Less commonly reported events were somnolence and insomnia, which were reported also at a comparable rate with placebo and other new generation antihistamine controls.
Rarely reported events in decreasing order of frequency included dizziness, fatigue, anorexia, nervousness, nausea, epistaxis, rhinitis, lacrimal gland disorder, asthenia, hyperkinesia, constipation, dyspepsia, palpitation, tachycardia, thirst, agitation, irritability, coughing, dyspnea, nasal irritation and pharyngitis.
With the exception of headache, which was occasionally severe, most adverse events associated with Clarinase 24 Hr Extended Release were mild to moderate in severity.
During the marketing of loratadine, alopecia, anaphylaxis (including angioedema) and abnormal hepatic function have been reported rarely.
There have been rare post-marketing reports of mechanical upper gastrointestinal tract obstruction in patients taking Clarinase 24 Hr Extended Release. In most of these cases, patients have had a history of difficulty in swallowing tablets or have had known upper gastrointestinal narrowing or abnormal esophageal peristalsis.