Study shows IM injectable is effective for 2 weeks.
Many patients with schizophrenia do not take their medication as prescribed. Researchers have been studying ways to improve compliance by providing long-acting relief. Data suggest that a long-acting, injectable formulation of risperidone (Risperdal/Janssen) provides consistently reliable symptom relief when administered as an intramuscular injection given every two weeks. The medication is gradually released to provide consistent blood levels from tiny microspheres made of a biodegradable polymer.