Cannabinoid hyperemesis syndrome (CHS), is characterized by recurrent episodes of severe nausea and intractable vomiting, preceded by chronic use of cannabis. A pathognomonic characteristic is compulsive bathing in hot water. The resolution of the problem occurs when cannabis use is stopped. However, patients are often reluctant to discontinue cannabis. Treatment with anti-emetic medication is ineffective. Case series suggested haloperidol as a potential treatment. Other antipsychotics as olanzapine has been used as anti-emetic treatment in chemotherapy.

To describe three cases of patients with CHS whom showed a successful response to olanzapine, even when, haloperidol had failed.

To present an alternative treatment for CHS which can offer benefits over haloperidol.

We present three cases of patients who suffered from CHS and were admitted to emergency department. All patients were treated with olanzapine after conventional anti-hemetic treatment failure. One patient was also unsuccessfully treated with haloperidol.

All three patients showed a good response to olanzapine treatment. Different presentations were effective: velotab and intramuscular. Their nausea, vomits and agitation were ameliorated. They could be discharge after maintained remission of symptoms.

Olanzapine should be considered as an adequate treatment for CHS. Its suitable receptorial profile, its availability in different routes of administration and its side effects profile could offer some benefits over haloperidol.

The authors have not supplied their declaration of competing interest.