The aim of the present study was to describe incidences of restrictive interventions and the association of methamphetamine use at an acute adult inpatient mental health unit in metropolitan Melbourne, Victoria, Australia. A total of 232 consecutive consumer admissions to the inpatient unit across a 3-month period were described for illicit substance use and the use of restrictive interventions (seclusion, mechanical restraint, and physical restraint) prior to and during admission. Of all admissions, 25 (10.8%) involved consumers subjected to a restrictive intervention. Methamphetamine use was either self-reported or detected by saliva test for 71 (30.6%) consumers. Following multivariate analyses, methamphetamine use (odds ratio (OR): 7.83, 95% confidence interval (CI): 2.33-26.31) and restrictive intervention in the emergency department prior to admission (OR: 8.85, 95% CI: 2.83-27.70) were significant independent predictors of the use of restrictive interventions after inpatient admission. Anecdotal observations provided by clinical mental health staff that consumers intoxicated with methamphetamine appear to require restrictive intervention more frequently than other consumers was confirmed with the results of the current study. As the state of Victoria in Australia is on a pathway to the elimination of the use of restrictive interventions in mental health services, clinicians need to develop management strategies that provide specialist mental health care using the least-restrictive interventions. Although 26.8% of methamphetamine users were secluded after admission, restrictive interventions should not be the default management strategy for consumers who present with self-report or positive screen for methamphetamine use.