Investigation into the efficacy of Chlorpromazine as a second line therapy for Cannabis Hyperemesis.

INTERVENTION: A single dose of metaclopramide 10mg intravenous (iv) and tropisetron 2mg Intravenous (iv) given to all patients in trail. A single dose of Chlorpromazine 25mg in normal saline 1L intravenous (iv) given to treatment group. CONDITION: Cannabinoid Hyperemesis Syndrome PRIMARY OUTCOME: Reduction of self‐recorded episodes of vomiting in the chlorproamzine group SECONDARY OUTCOME: nausea patient satisfaction INCLUSION CRITERIA: Intractable vomiting in patients with known cannabis use and no other pathological cause identified. Informed consent given.