We compared the risk of death by suicide following hospital presentation for self-harm according to site of self-cut/stab.

We included 54 999 self-harm presentations (involving 31 419 individuals) to hospitals in the Multicentre Study of Self-harm in England (1/1/2004–31/12/2014), with mortality follow-up to 31/12/2019. Information on method of self-harm was obtained through monitoring in hospitals. Information about mortality was obtained through linkage with NHS Digital. We assessed the association of site of self-cut with death by suicide using mixed effect models.

In total, 10 790 (19.6%) hospital presentations involved self-cutting/stabbing, 7489 of which (69.4%) were due to laceration to the arm/wrist alone, 1846 episodes (17.1%) involved cutting elsewhere on the body, and 1455 (13.5%) were due to laceration to unknown site. Controlling for confounders, presentation to a hospital following self-cut/stab to bodily parts other than wrist/arm was associated with greater chance of subsequent suicide relative to presentation after self-poisoning alone [adjusted odds ratio (aOR) 1.75, 95% confidence interval (CI) 1.03–2.96, p = 0.038]. The likelihood of suicide after presentation for cutting/stabbing the wrist/arm alone was comparable to that of patients who had self-poisoned alone. Presentations after laceration involving the neck were associated with a four-fold greater chance of subsequent suicide relative to self-poisoning (aOR 4.09, 95% CI 1.80–9.30, p = 0.001).

Patients who attend hospital after self-cutting/stabbing are a heterogeneous group in terms of characteristics, methods of cutting/stabbing and risk of subsequent suicide. Risk of suicide is greater in individuals who self-cut/stab to parts of the body other than the wrist or arm, especially the neck.

Evaluate the relationship between naloxone dose (initial and cumulative) and opioid toxicity reversal and adverse events in undifferentiated and presumed fentanyl/ultra-potent opioid overdoses.

We searched Embase, MEDLINE, Cochrane Central Register of Controlled Trials, DARE, CINAHL, Science Citation Index, reference lists, toxicology websites, and conference proceedings (1972 to 2018). We included interventional, observational, and case studies/series reporting on naloxone dose and opioid toxicity reversal or adverse events in people >12 years old.

A total of 174 studies (110 case reports/series, 57 observational, 7 interventional) with 26,660 subjects (median age 35 years; 74% male). Heterogeneity precluded meta-analysis. Where reported, we abstracted naloxone dose and proportion of patients with toxicity reversal. Among patients with presumed exposure to fentanyl/ultra-potent opioids, 56.9% (617/1,085) responded to an initial naloxone dose ≤0.4 mg compared with 80.2% (170/212) of heroin users, and 30.4% (7/23) responded to an initial naloxone dose >0.4 mg compared with 59.1% (1,434/2,428) of heroin users. Among patients who responded, median cumulative naloxone doses were higher for presumed fentanyl/ultra-potent opioids than heroin overdoses in North America, both before 2015 (fentanyl/ultra-potent opioids: 1.8 mg [interquartile interval {IQI}, 1.0, 4.0]; heroin: 0.8 mg [IQI, 0.4, 0.8]) and after 2015 (fentanyl/ultra-potent opioids: 3.4 mg [IQI, 3.0, 4.1]); heroin: 2 mg [IQI, 1.4, 2.0]). Where adverse events were reported, 11% (490/4,414) of subjects experienced withdrawal. Variable reporting, heterogeneity and poor-quality studies limit conclusions.

Practitioners have used higher initial doses, and in some cases higher cumulative naloxone doses to reverse toxicity due to presumed fentanyl/ultra-potent opioid exposure compared with other opioids. High-quality comparative naloxone dosing studies assessing effectiveness and safety are needed.