An assembly of devices intended to be used by a healthcare professional (e.g., orthopaedist, pain management specialist, rheumatologist) for the intermittent delivery of liquid medication in a controlled manner to manage pain in various applications [e. g, intra-articular, epidural site(s), and nerve blocks]. It typically consists of a mains electricity (AC-powered) multichannel delivery pump, a disposable cassette, vial transfer spikes, and a handpiece/tubing set. The system automates aspects of the injection procedure otherwise performed by manual syringe and typically records treatment information for patient records; it may interface with an external ultrasound (US) system.