Table 1.

LINC-II eligibility criteria

Inclusion criteria	Exclusion criteria
Age 18 years or older	Not fluent in Russian
HIV-positive	Cognitive impairment precluding informed consent
Hospitalized at narcology hospital	Breastfeeding or being pregnant
History of injection drug use	ART use in the past 30 days prior to hospitalization
Provision of two contacts to assist with follow-up	Acute severe psychiatric illness (i.e., answered yes to any of the following: past three month active hallucinations; mental health symptoms prompting a visit to the emergency room or hospital; mental health medication changes due to worsening symptoms; presence of suicidal ideations)
Address within St. Petersburg or districts within 100 km of St. Petersburg	Known history of liver failure
Possession of a home or mobile phone	Known hypersensitivity to naltrexone
Ability and willingness to comply with all study protocols and procedures	Aspartate aminotransferase (AST) or alanine aminotransferase (ALT) greater than 5 times the upper limit of normal
	Severe thrombocytopenia
	Known coagulation disorder/taking anticoagulation medications
	Body habitus that precludes intramuscular injection (e.g., BMI < 17 or > 45)
	Known history of Raynaud’s disease, Itsenko-Cushing syndrome, generalized mycoses, glaucoma, or osteoporosis
	Planned surgeries in the next 12 months