Information regarding acute overdosage with desloratadine is limited to experience from post-marketing adverse event reports and from clinical trials conducted during the development of the CLARINEX® product. In the reported cases of overdose, there were no significant adverse events that were attributed to desloratadine. In a dose ranging trial, at doses of 10 mg and 20 mg/day, somnolence was reported.

Single daily doses of 45 mg were given to normal male and female volunteers for 10 days. All ECGs obtained in this study were manually read in a blinded fashion by a cardiologist. In the CLARINEX®-treated subjects, there was a mean increase in the maximum heart rate of 9.2 bpm relative to placebo. The QT interval was corrected for heart rate (QTc) by both the Bazett and Fridericia methods. Using the QTc (Bazett), there was a mean increase of 8.1 msec in the CLARINEX®-treated subjects relative to placebo. Using QTc (Fridericia) there was a mean increase of 0.4 msec in CLARINEX®-treated subjects relative to placebo. No clinically relevant adverse events were reported.

In large doses, sympathomimetics may give rise to giddiness, headache, nausea, vomiting, sweating, thirst, tachycardia, precordial pain, palpitations, difficulty in micturition, muscle weakness and tenseness, anxiety, restlessness, and insomnia. Many patients can present a toxic psychosis with delusions and hallucinations. Some may develop cardiac arrhythmias, circulatory collapse, convulsions, coma, and respiratory failure.

In the event of overdose, consider standard measures to remove any unabsorbed drug. Symptomatic and supportive treatment is recommended. Desloratadine and 3-hydroxydesloratadine are not eliminated by hemodialysis.

Lethality occurred in rats at oral doses of 250 mg/kg or greater (estimated desloratadine and desloratadine metabolite exposures were approximately 120 times the AUC in humans at the recommended daily oral dose). The oral median lethal dose in mice was 353 mg/kg (estimated desloratadine exposure was approximately 290 times the human daily oral dose on a mg/m² basis). No deaths occurred at oral doses up to 250 mg/kg in monkeys (estimated desloratadine exposure was approximately 810 times the human daily oral dose on a mg/m² basis).

CLARINEX-D® 12 HOUR (desloratadine and pseudoephedrine sulfate) Extended Release Tablets are contraindicated in patients who are hypersensitive to this medication or to any of its ingredients, or to loratadine. Due to its pseudoephedrine component, it is contraindicated in patients with narrow-angle glaucoma or urinary retention, and in patients receiving monoamine oxidase (MAO) inhibitor therapy or within fourteen (14) days of stopping such treatment (see DRUG INTERACTIONS section). It is also contraindicated in patients with severe hypertension, severe coronary artery disease, and in those who have shown hypersensitivity or idiosyncrasy to its components, to adrenergic agents, or to other drugs of similar chemical structures. Manifestations of patient idiosyncrasy to adrenergic agents include: insomnia, dizziness, weakness, tremor, or arrhythmias.

Last reviewed on RxList: 2/4/2009
This monograph has been modified to include the generic and brand name in many instances.