Guanfacine adverse effects

The adverse effect profile of guanfacine is similar, with the exception that dry mouth and sedation are less common (Wilson et ah, 1986). Blood pressure was not... 

The most common side effect of clonidine is dose-dependent sedation that usually subsides after 2 to 3 weeks of therapy. Of concern are reports of bradycardia, rebound hypertension, heart block, and sudden death. Four children have died on the combination of methylphenidate and clonidine however, complicating factors make it impossible to link the drug combination directly with the cause of death. Of 10,060 children exposed to clonidine and assessed by a poison control center over a 7-year period, moderate (19%) to major (2%) toxic effects (bradycardia, hypotension, and respiratory depression) including one death were reported. Overdoses, concurrent clonidine and stimulant administration, as well as missed doses of clonidine aU add to the risk of adverse cardiovascular events. Similar adverse-effect concerns apply to treatment with guanfacine, although its U2a selectivity may result in less sedation and hypotension than clonidine. ... 

For clonidine and guanfacine the most common adverse effect is sedation. Fortunately, tolerance usually develops to this effect over days to weeks. The most potentially serious side effects are cardiovascular (see the ADHD section). Other 2-agonist side effects include dry mouth, constipation, headache, mood changes, and even a temporary worsening of tics in 10% of patients. 

Overall, although the frequency of troublesome adverse effects produced by guanfacine is similar to that produced by clonidine and the other centrally acting sympatholytics, their incidence and severity are lower with guanfacine. Unlike clonidine, abrupt discontinuation of guanfacine rarely results in rebound hypertension. When a withdrawal syndrome has occurred, its onset was slower and its symptoms less severe than the syndrome observed with clonidine. 

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