Clonidine and guanfacine IR vs ER: Old drugs with “new” formulations

After a long history of use for hypertension, clonidine and guanfacine have re-emerged on the market as treatment options for attention-deficit/hyperactivity disorder, particularly in patients who are unable to tolerate or need an alternative to stimulant medications as well as those who have residual symptoms despite adequate therapy with stimulants. In recent years, new formulations of long-acting clonidine and guanfacine have come to market. The purpose of this article is to review the pharmacokinetic properties and clinical utility of these new agents while comparing the medications and parent compounds in terms of dosing, adverse effects, and costs of treatment.