Naltrexone Linked to Injection-Site Reactions

Nearly 200 people receiving extended-release naltrexone (Vivitrol) have reported adverse injection-site reactions, including cellulitis, induration, hematoma, abscess, sterile abscess, and necrosis, the FDA announced on Tuesday. Naltrexone is used for alcohol dependence.

Clinicians should advise patients to monitor the injection site for pain, swelling, tenderness, induration, bruising, pruritus, or redness that does not improve or gets worse within 2 weeks. Patients with worsening reactions should be promptly referred to a surgeon.

Naltrexone is given as an intramuscular gluteal injection. The FDA says that the reaction risk may increase if the drug is deposited in fatty tissue and not muscle.