Clonidine pharmacological properties

If these measures fail, clonidine, fluphenazine, clonazepam, or carbamazepine should be tried. The pharmacologic properties of these drugs are discussed elsewhere in this book. Clonidine reduces motor or vocal tics in about 50% of children so treated. It may act by reducing activity in noradrenergic neurons in the locus coeruleus. It is introduced at a dose of 2-3 mcg/kg/d, increasing after 2 weeks to 4 mcg/kg/d and then, if required, to 5 mcg/kg/d. It may cause an initial transient fall in blood pressure. The most common adverse effect is sedation other adverse effects include reduced or excessive salivation and diarrhea. Phenothiazines such as fluphenazine sometimes help the tics, as do dopamine... 

Clonidine has also been found to exhibit several other pharmacologic properties that, in some cases, do not seem to be related to its a-adrenoceptor mechanism. Effectiveness in glaucoma is one that is. It is experimental, but may be a property shared by other a2-agonists. 

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