<h3>Objective:</h3> To present a case of RCVS induced by ketamine infusions compounded with triptan and NSAID usage. <h3>Background:</h3> A 47 yo female with a history of depression and migraines presented with a persistent headache for 3 days. On the day of presentation, the patient reported the “worst headache of her life”. The headache was “sharp and squeezing”, frontal and retro-orbital in location, radiating to the back of her head, and exasperated by laying flat. The patient reported taking multiple high-dose NSAIDs along with sumatriptan. She had completed a 3-week course of ketamine infusions (75 mg twice weekly for depression) with last infusion 2 days prior to presentation. She was also on a chronic SSRI for depression. Patient denied any alcohol or current recreational drug use, but did report a history of opioid dependency. Initial CT head demonstrated a moderate-sized right frontal lobe subarachnoid and a small subarachnoid in the right posterior parietal lobe. CTA of head and neck demonstrated vasospasm of the left supraclinoid ICA, left M1 segment, and basilar artery. The location, radiographic appearance, and temporal course was consistent with RCVS. CT Angiogram was negative for any luminal irregularity, focal stenosis, or narrowing. MRI brain with contrast redemonstrated the subarachnoid hemorrhage without evidence of a vasculitic process. Lab work-up was negative for ANA, C4, C3, Sjogren’s Antibodies, RF, Anti-DNAs Ab. CRP and ESR were mildly elevated suggesting mild inflammation. <h3>Design/Methods:</h3> N/A <h3>Results:</h3> The etiology of the headache and subarachnoid hemorrhage was suspected to be medication induced RCVS in the setting of concomitant use of sumatriptan, SSRI, and high doses of ketamine. <h3>Conclusions:</h3> Although a rare phenomena, RCVS is a concerning cause of thunderclap headache that should be recognized. RCVS is not a common occurrence with ketamine usage but clinicians should be aware is this possible adverse effect. <b>Disclosure:</b> Dr. Mufti has nothing to disclose. Dr. Canlas has nothing to disclose. Dr. Ritenuti has nothing to disclose.