February 2009

Combination Approach to Childhood Anxiety
In a study of children with anxiety disorders, the combination of cognitive behavioral therapy and an antidepressant was superior to either treatment alone.

Antipsychotic-Induced Weight Gain: Management Without Meds
Several behavioral interventions effectively promote weight loss in patients taking antipsychotics.

Allopurinol: Novel Treatment for Mania?
Allopurinol (Lopurin and others) as an adjunct to lithium may help improve manic symptoms in patients with bipolar disorder.

In Brief
Behavioral Risk Factors Mediate Hospitalization and Mortality; International Internet Day of Action Results in Drug Seizures

Adjunctive Estrogen for Schizophrenia?
Exogenously administered estradiol added to antipsychotic therapy might benefit women with schizophrenia.

Injection Site Reactions with Naltrexone
Injections of extended-release naltrexone (Vivitrol) can cause serious skin reactions.

Injection Site Reactions with Naltrexone

February 2009

Naltrexone (Vivitrol) is an opiate antagonist that was approved by the US Food and Drug Administration (FDA) in 2006 to assist in the treatment of alcohol dependence. Naltrexone is indicated for patients who can abstain from alcohol and are not currently drinking. Patients taking naltrexone should participate in a comprehensive management program that includes psychosocial support. Naltrexone is contraindicated for patients currently taking opioid analgesics, those dependent on opioids, and in patients in active opioid withdrawal.

In addition to oral preparations, naltrexone is available in an injectable, extended-release formulation. On August 12, 2008, the FDA issued a warning based on 196 reports it had received of injection site reactions with intramuscular (IM) naltrexone.1 The reactions included cellulitis, induration, hematoma, abscess, sterile abscess, and necrosis. Sixteen patients required surgery.

Intramuscular naltrexone is given as a gluteal injection. It should not be administered intravenously or subcutaneously. Injection into fatty tissue increases the risk of serious injection site reactions. Women may have a greater risk of inadvertent administration into fatty tissue due to higher gluteal fat thickness. The FDA reminds clinicians that, due to variations in weight, the thickness of subcutaneous tissue to be traversed in the gluteal muscle will vary from patient to patient.

Naltrexone injections may be followed by pain, redness, itching, bruising, and swelling. Injection site reactions can quickly worsen and cause permanent skin damage. If an injection site reaction does not improve, surgery may be required.

1Mitka M: Alcohol dependence drug prompts warning. JAMA 2008;300:1289.