The combination drug dextromethorphan/quinidine (AVP-923), traditionally used to treat pseudobulbar affect, is under investigation for the treatment of a variety of other neurological and neuropsychiatric conditions including agitation associated with Alzheimer's disease, among others. In 2013, a randomized clinical trial found that dextromethorphan may reduce the overall discomfort and duration of withdrawal symptoms associated with opioid use disorder. When combined with clonidine, dextromethorphan reduced the overall time needed for withdrawal symptoms to peak by 24 hours while reducing severity of symptoms compared to clonidine alone.