“Chill Packs” Self-Administered Olanzapine as Psychiatric Harm Reduction for Methamphetamine-Induced Psychosis: A Narrative Review of the Existing Evidence Base

The prevalence and health consequences of methamphetamine use disorder have risen across the United States, including methamphetamine-induced psychosis (MIP). A promising, novel approach to address MIP is the use of ‘chill packs’, a psychiatric harm reduction intervention for people using methamphetamine. Chill packs consist of several low-dose olanzapine tablets (an antipsychotic medication) that can be self-administered in the event of methamphetamine-induced insomnia, anxiety, paranoia, delusions, or other dysphoric symptoms. One recent study assessed the effectiveness of an implementation of chill packs by the San Francisco Department of Health and found that repeat psychiatric emergency visits dropped by 32% after two-months and 13% after six-months. While these findings are promising, more research is needed to evaluate the efficacy and generalizability of this intervention. Here we provide a narrative review of indirect evidence and contextual information for related dynamics, including: the epidemiology of MIP, clinical data supporting the use of olanzapine versus other antipsychotics for MIP, evidence supporting as-needed use of antipsychotics in the outpatient setting, as well as ethnographic and other data describing the potential for misuse of olanzapine and other antipsychotics. Overall, the literature supports that the prevalence of MIP is rising sharply, causing increased psychiatric burden. This is also linked to overdose risk among patients that use illicit fentanyl or other sedatives to “come down” after periods of heavy methamphetamine use. Olanzapine has demonstrated comparable efficacy for treating MIP to other antipsychotics with enhanced short-term sedative effects, despite a higher burden of long-term metabolic side effects. Olanzapine has very little documented misuse risk, although other agents in its class, especially quetiapine, have higher street value. Qualitative research highlights that some groups already self-administer olanzapine as a ‘trip killer’ to manage distressing psychiatric side effects from illicit drug use. Overall, we find substantial indirect contextual evidence supporting further trials to evaluate chill packs as a harm-reduction intervention for MIP, and provide recommendations for research needed to fill gaps in the literature for this promising, albeit new and little-studied intervention.