No, social workers do not prescribe medications. Social workers are "case managers" - they manage to ensure that a patient has access to multiple disciplines, such as psychologists, psychiatrists, speech therapists, and many other social interventions as might be appropriate to each individual case. Your insurance company generally requires a social worker in order to determine what other professionals are needed. That said, you also have what are termed "licensed clinical social workers" which are what most people consider "therapists". Whether these individuals can prescribe medications is dependent upon state law.