Dopamine antagonists and topical capsaicin for cannabis hyperemesis syndrome (CHS) in the emergency department: a systematic review of direct evidence.

There is limited direct evidence on the efficacy of dopamine antagonists or capsaicin for treating CHS in the ED. Current evidence is mixed for capsaicin and potentially beneficial for dopamine antagonists. Because of the small number of studies, small number of participants, lack of standardization of treatment administration, and risk of bias of the included studies, methodologically rigorous trials on both types of intervention are needed to directly inform ED management of CHS.