Infective endocarditis (IE) is a serious complication of injection drug use. Right-sided IE encompasses 5-10% of all IE cases, with the majority involving the tricuspid valve (TV). The predominant causal organism is Staphylococcus aureus. Most cases of right-sided IE can be successfully treated with antimicrobials, but approximately 5-16% require eventual surgical intervention. We report the case of a 36-year-old female with active injection drug use who developed methicillin-sensitive Staphylococcus aureus IE of the tricuspid valve. Associated with poor adherence to medical therapy as a consequence of opioid addiction, she developed septic emboli to the lungs and an intravascular abscess in the left main pulmonary artery. These long-term potentially fatal, sequelae of incompletely treated IE require surgical intervention, as medical therapy is unlikely to be sufficient. Surgical management may involve TV replacement, pulmonary artery resection, and pneumonectomy. Prevention of these complications may have been achieved by concurrent opioid addiction therapy. An intravascular pulmonary artery abscess is a novel complication of advanced IE that has not been previously reported. This complication likely arose due to incomplete IE treatment as a consequence of opioid addiction, highlighting the need for concurrent addiction management. Intravenous antimicrobial therapy is likely not adequate, and surgical intervention, including pulmonary artery resection and pneumonectomy may be necessary.