As of January, 2017, there are 11 FDA approved naloxone products manufactured by six different companies. One product is not recommended for layperson and take-home naloxone use. It is very complicated to assemble resulting in several reports of failed assembly in the field during overdose emergencies- (Naloxone Hydrochloride Injection, USP, 0.4 mg/mL Carpuject™ Luer Lock Glass Syringe (no needle) NDC# 0409-1782-69 by Pfizer).
The remaining product characteristics are detailed in this comparison chart:
