The U.S. Food and Drug Administration (FDA) has not approved any drug for the direct treatment of stuttering.[1] However, the effectiveness of pharmacological agents, such as benzodiazepines, anticonvulsants, antidepressants, antipsychotic and antihypertensive medications, and dopamine antagonists in the treatment of stuttering has been evaluated in studies involving both adults and children.[66] A comprehensive review of pharmacological treatments of stuttering in 2006 concluded that few of the drug trials were methodologically sound.[66] Of those that were, only one, not unflawed study,[67] showed a reduction in the frequency of stuttering to less than 5% of words spoken. In addition, potentially serious side effects of pharmacological treatments were noted,[66] such as weight gain, sexual dysfunctions and the potential for blood pressure increases. There is one new drug studied especially for stuttering named pagoclone, which was found to be well-tolerated "with only minor side-effects of headache and fatigue reported in a minority of those treated".[68]