Fellowship in Medical Toxicology

Objectives

• Learn and incorporate the knowledge and skills necessary to provide excellent bedside and telemedicine care to patients with a range of toxicologic issues.
• Acquire in-depth understanding of the core content of medical toxicology, including the diagnosis and management of poisoned patients, substance use and withdrawal, occupational and industrial exposures, environmental toxicology and toxinology, laboratory science, public health, and more.
• Develop facility in acquiring, critically evaluating, and incorporating current and past literature that supports our practice, with an emphasis on understanding the controversies and competing views.
• Obtain a substantial experience in toxicosurveillance, sentinel event detection, and investigation, incorporating clinical practice within the framework of a statewide poison control center.
• Attain the skills and spirit of inquiry necessary to design and execute research in medical toxicology.
• Become an effective representative for the specialty, through research, teaching, lecturing, publications, and public outreach.
• Attain the competence to practice independently and pass the board certification examination.

Clinical Training

Bedside Consultation Service

The Inpatient Medical Toxicology Consult Service at University Hospital is a high-volume, tertiary care service based at Rutgers New Jersey Medical School. We manage approximately 600–800 consultations annually, serving a diverse patient population that includes complex medical and surgical cases, as well as patients from our regional liver transplant program, and Emergency Department observation unit. Our team specializes in the evaluation and management of a broad range of toxicologic presentations, with a focus on complications related to substance use disorders, including acute intoxication, withdrawal syndromes, and toxicologic emergencies.

We work in close collaboration with Addiction Medicine to provide integrated care for patients with substance use disorders, bridging acute toxicologic management with longer-term treatment and harm reduction strategies. Our consultative service plays a critical role in supporting critical care units, emergency medicine, internal medicine, and pediatric services, offering expertise in areas such as toxidrome recognition, antidote use, drug-induced organ injury, and complex pharmacologic interactions.

NJPIES

The New Jersey Poison Information and Education System (NJPIES) is the statewide poison center for New Jersey, and the home and heart of the fellowship. As previously mentioned, we serve a population of more than 9 million, with greater than 50,000 calls annually from the public and healthcare providers. Day and night, our fellows and faculty work closely with our Clinical Specialists in Poison Information (CSPIs), who field the initial call or chat. NJPIES is also the physical home of the fellowship, and where our offices are located. Fellows participate not only in the active call volume, but also the toxicosurveillance that the poison center provides. Additionally, as a statewide-resource, the fellowship participates in education and outreach on a variety of topics, interfacing with public health entities such as the Department of Health, education systems, insurance companies, community centers, etc.

Outpatient Medical Toxicology Clinic

Our outpatient clinic, housed in the same building as the poison center, is where we cover a different aspect of medical toxicology that does not concern the acute care of patients. Our clinic, which is by referral only, meets once weekly to allow us to see patients referred by the greater community, or to provide an avenue for follow up for patients that we cared for in the hospital.

The combined fellowship in Addiction Medicine and Medical Toxicology is the only one of its kind. We are proud to provide this valuable experience, which shortens the duration of training for the two specialties by six months. The integration of the two services and educational programs is a source of pride for both fellowships, and continues to evolve and grow. Currently, during the first year of training, combined fellows begin their longitudinal outpatient addiction clinic experience, typically one day a week, and grow their roster of patients. Additional experiences come through education and our monthly combined conference.

The joint fellowship has already demonstrated success through the awarding of two Medical Toxicology Foundation - National Institutes on Drug Abuse (MTF-NIDA) Dissemination Initiative grants (2024 - Dr. Tony Spadaro, and 2025 - Dr. Nicholas Imperato - one of our emergency medicine residents). In addition, Dr. Spadaro was accepted into the Research in Addiction Medicine Scholars (RAMS) Program as part of Cohort 13, with Dr. Greller serving as his institutional mentor. This NIDA funded program aims to develop skills in addiction research among physicians from accredited Addiction Medicine and Addiction Psychiatry fellowship programs across North America, and has a long track-record of robust and impactful scholarship.

The Addiction Medicine side of fellowship is housed in the Department of Psychiatry. They're faculty are composed of providers from internal medicine, psychiatry, family medicine, emergency medicine, and ob/gyn. Rotations while on addiction medicine include the addiction medicine consult service at UH, outpatient addiction medicine at the CARE (Comprehensive Addiction Resources & Education) center, prenatal/peripartum addiction medicine clinic, Veterans Affairs, methadone clinic, and correctional facilities.

• A practice location with a diverse patient population, located at the one of the three Level 1 trauma centers in the State of New Jersey, with a broad variety of clinical experiences and exposures.
• Directly integrated and housed at the only poison center in the State, with a broad case experience, approximately 50k poisoning-related calls per year. Serve as the primary backup for our exemplary Certified Specialists in Poison Information (CSPIs), with attending backup 24/7.
• Renowned faculty and departmental and program leadership with a passion and devotion to medical toxicology education and professional development.
• An active bedside clinical consultation service at University Hospital, with over 800 consults per year, managing critical overdose, withdrawal, and toxicology patients of all ages at all levels of care.
• An outpatient toxicology clinic that provides experience with chronic toxicologic illness, and allows for follow up for patients initially managed by the acute service in the hospital or state.
• A robust educational program, including daily didactics, teaching of rotating residents and students, journal clubs, case conferences, and many other activities devoted to fellow education.
• Direct relationship and cross-teaching with the faculty and fellows of the Addiction Medicine fellowship training program, participation on clinical rounds, and departmental guideline development opportunities.
• Regular clinical exposure to occupational and industrial toxicology through our relationship with the preeminent Environmental and Occupational Health Sciences Institute (EOSHI) of Rutgers University.
• Myriad opportunities to learn public health outreach and education, poison prevention initiatives, poison center administration, and more.
• Participation through NJPIES in consultation and management of public health emergencies (e.g., COVID-19, carbon monoxide, industrial releases.)
• Vast opportunities for research, administration, mentorship, and teaching
• Access to the resources of a large university system, including an extensive biomedical library, teaching opportunities at the graduate level, and dynamic collaboration with other schools including the Rutgers Department of Medical Informatics, the Ernest Mario School of Pharmacy, Rutgers School of Public Health, and the Rutgers Center for Pharmacoepidemiology and Treatment Science (PETS)

Recent Publications

1. Parris, MA, et al. ACMT position statement : no evidence that tampons cause metal poisoning. J Med Toxicol 2025; 21:106-107.
2. Spadaro A, Nath J, Mok T, Chen C, Nelson L, Santos C. Parenteral Buprenorphine for Opioid Withdrawal: A Case Series. J Stud Alcohol Drugs. 2025 May;86(3):410-415. doi: 10.15288/jsad.24-00099. Epub 2024 Sep 27. PMID: 39330952.
3. Thakrar AP, Zwiebel SJ, Christine PJ, Spadaro A, Davis MH, Bhatia R, Rohacs N, Xu L, Perrone J, Lowenstein M. Manifestations of potential xylazine withdrawal: A retrospective cohort study with nested case series. Drug Alcohol Depend. 2025 Jul 1;272:112681. doi: 10.1016/j.drugalcdep.2025.112681. Epub 2025 Apr 30. PMID: 40334325.
4. Aldy K, Krotulski A, Brent J, Campleman S, Culbreth R, Logan B, Wax P, Amaducci A, Judge B, Levine M, Schwarz E, Calello DP, Meaden CW, Shulman J, Hughes A, Hendrickson R, Carpenter J, Buchanan J, Manini AF; Toxicology Investigators Consortium (ToxIC) Fentalog Study Group. Emergency Department Patients with Para-Fluorofentanyl Overdose. J Emerg Med. 2025 May;72:56-69. doi: 10.1016/j.jemermed.2024.11.020. Epub 2024 Nov 20. PMID: 40288941; PMCID: PMC12064398.
5. Tran T, Imperato N, Dym A, Rosania A, Nelson L, Ramdin C, Santos C. The promising use of an emergency department observation unit to manage patients with opioid use disorder. Am J Emerg Med 2025; 6:152-155.
6. Dicker F, et al with Meaden and Calello (Fentalog Study Group). Tramadol as a fentanyl adulterant: prevalence and management in a ToxIC Fentalog study prospective cohort. Am J Emerg Med 2025; 89:169-173.
7. Das S, et al with Spadaro, A: Two-layer retrieval-augmented generation framework for low-resource medical question answering using reddit data: Proof of concept study. J Med Internet Res 2025; 6:e66220.
8. Counts CJ, Spadaro AV, Cerbini TA, Krotulski AJ, Walton SE, Greller HA, Nelson LS, Ruck BE, Hung O, Logan B, Calello DP. An outbreak of synthetic cannabinoid-adulterated tianeptine products in New Jersey – Case Series. J Med Toxicol 2025; 21:253-259.
9. Mudan, A, Lebin JA. Suicides by sodium nitrite reported to America’s Poison Centers: 2020-2023. J Clin Psychiatry 2025; 22:86.
10. Spadaro TS, Parris M, Valestra P, Greller HA, Calello DP, Nelson LS, Meaden CW. Prolonged infusion of flumazenil for the reversal of sedation from chlordiazepoxide: a case report. Toxicology Communications. doi: 10.1080/24734306.2024.2395699
11. Chen B, Counts CJ, Maresca P, Greller HA, Heller MJ. Simultaneous Cases of Familial Hypokalemic Periodic Paralysis Induced by Illicit Injection of Betamethasone. The Journal of Emergency Medicine. Published online 2024. doi:10.1016/j.jemermed.2024.09.021
12. Counts CJ, Spadaro AV, Cerbini TA, Walton SE, Greller HA, Nelson LS, Ruck BE, Hung O, Logan B, Calello DP.. An Outbreak of Synthetic Cannabinoid-Adulterated Tianeptine Products in New Jersey – Case Series. J Med Toxicol. Published online March 18, 2025. doi:10.1007/s13181-025-01068-7
13. Spadaro A, Perrone J, Nelson LS, Greller HA. Reining It In: Xylazine Overdose. Critical Decisions in Emergency Medicine, May 2025 39(5): 30-37.
14. Spadaro A, Calello D, Counts C, Cerbini T, Nelson L, Greller H. Rapid transition from a continuous naloxone infusion to sublingual buprenorphine after an opioid overdose: a case series. Accepted to Substance Use & Addiction Journal. doi:10.1177/29767342251356351

Curriculum

Fellowship is an incredible learning experience, with a vast amount of information to absorb. A majority of the learning comes through the interaction of clinical cases with bedside care, discussion, reading, supplemental materials, and follow up. This is all supported through a formal curriculum and the knowledge and teaching of the faculty and CSPIs, as well as the diversity of cases that come through NJPIES on a daily basis.

• Fellows rounds and case review - daily, mediated by faculty and fellows
• Didactic rotator rounds - daily, coordinated between fellows, faculty, and ATEAM
• Core content - regular reading assignments from the Core Content of Medical Toxicology, with fellow generated question bank / flashcards, which complements our board review efforts for Fellow Friday
• Structure of the Week, Toxicology History of the Month
• “Metal Monday", “Occ Tox Tuesday”, “Pharmacology Friday”, and other alliterative educational sessions
• Journal Club - recurring weekly - twice monthly with current articles of interest, once monthly with classic content, and once monthly in collaboration with ATEAM
• ATEAM - Academic Toxicology Education Alliance of the Mid-Atlantic. An exciting collaborative educational effort between our fellowship (NJPIES), the Maryland Poison Center, and The Philadelphia Poison Center. Provides core content lectures for rotators and fellows, regional case conference and presentation, a journal club, and more. Multiple opportunities for fellow engagement and presentation.
• The American College of Medical Toxicology (ACMT) National Case Conference, National Journal Club
• Regular participation in the Rutgers University Hospital Department of Emergency Medicine Wednesday conference

Conferences

• ATEAM Case Conference
• ATEAM Journal Club
• ATEAM didactics
• ACMT National Case Conference
• ACMT National Journal Club
• NYCPCC Consultants Conference
• Rutgers NJMS EM
• Addiction Medicine / Medical Toxicology Joint Conference
• EOSHI Occupational Medicine Grand Rounds

Teaching Opportunities

• Rotator rounds
• Fellow Friday teaching
• NJMS Core Curriculum
• Graduate Student lectures

Research

Research opportunities abound at Rutgers. As part of the training, fellows are expected to explore and develop an area of interest and expertise, and utilize their training and mentorship to develop an original project. This scholarly pursuit can take many forms, from bench research to development of a curriculum to grant-funded clinical trials. We have access to the full resources of the University, the experience of the faculty, and the research team in the Department of Emergency Medicine.

Leadership

• Howard A. Greller, MD
  • Program Director, Medical Toxicology Fellowship
  • Co-Director, Combined Fellowship in Addiction Medicine and Medical Toxicology
• Diane P. Calello, MD
  • Medical and Executive Director of New Jersey Poison Information and Education System (NJPIES)
  • Division Chief - Division of Medical Toxicology and Addition Medicine
• Harsh Sule, MD - Interim Chair, Department of Emergency Medicine

Faculty

Diane P. Calello, MD
Dr. Calello is the Executive and Medical Director of the New Jersey Poison Information and Education System, and Professor of Emergency Medicine at Rutgers New Jersey Medical School. She is board certified in Pediatrics, Pediatric Emergency Medicine, Medical Toxicology, and Addiction Medicine, and is actively involved in national leadership in several professional organizations as well as state and federal advocacy efforts. She is on the Board of Directors for the American College of Medical Toxicology, on the CDC/AAPCC Toxicosurveillance Team, and participates in several multi-center research efforts including the study of fentanyl analogues through the ACMT and the leadership team of the Toxicology Investigators Consortium Registry. Her specific areas of interest include the impact of pediatric poisoning fatalities, environmental lead poisoning, the pediatric consequences of the opioid epidemic, substance use disorders, toxicosurveillance and population health, and the role of poison centers in public health emergencies.

Howard A. Greller, MD (he | him)
Dr. Greller is Associate Professor of Emergency Medicine, and the Program Director of the Medical Toxicology Fellowship. He is board certified in Emergency Medicine, Medical Toxicology, and Addiction Medicine. He currently serves as the Deputy Editor of the Journal of Medical Toxicology, and has served on the board of directors of both the American College of Medical Toxicology and the Medical Toxicology Foundation. He is co-founder and editor of the Tox and the Hound blog, and is the ‘&Howard’ of the Dantastic Mr. Tox & Howard podcast. He additionally promotes his educational outreach as co-host of the Emergency Medicine show on Sirius/XM Doctor Radio. Dr. Greller has an interest in the care and management of substance use disorders and withdrawal, toxicology education, and anything and everything having to do with caffeine.

Mehruba Parris, MD
Dr. Parris is an Associate Professor of Emergency Medicine at Rutgers New Jersey Medical School and serves as a Medical Toxicology Consultant for the New Jersey Poison Information and Education System. She currently directs the inpatient Medical Toxicology Consult Service at University Hospital and is the site director for the ACMT ToxIC Consortium at Rutgers NJMS. Board-certified in both Emergency Medicine and Medical Toxicology, Dr. Parris completed her fellowship in Medical Toxicology at Emory University/Centers for Disease Control and Prevention. Her professional interests include critical care toxicology, public and global health in toxicology, diversity in medical education, physician wellbeing, women in medicine, and patient safety and quality improvement.

Cynthia Santos, MD
Dr. Santos is currently the PI for several projects, including a SAMHSA-funded program focused on training and implementing novel pharmacological and non-pharmacological interventions for pain management to reduce opioid overuse. She serves as PI for another SAMHSA grant supporting our Opioid Response Team across Essex County, which administers MOUD and provides community-based linkage to care through a team consisting of a Nurse Practitioner, Paramedic, and Case Manager. She is the PI for a New Jersey Department of Health grant that expands urine drug screening for patients presenting with overdose and the site PI for an NIH-funded study evaluating the efficacy and safety of high-dose buprenorphine for MOUD.
Previously, she served as site PI for an NIH-funded study assessing the impact of ED observation units on outcomes in patients with OUD. She was PI for a grant supporting MOUD and harm reduction training for medical and surgical residents, nurse practitioner, and physician assistant programs. She led a SAEM/MTF-supported study on buprenorphine pharmacogenomics and served as PI for a SAMHSA grant that established an ED-based peer navigator program to connect patients to outpatient MOUD.

Christopher Meaden, MD
In addition to being the first graduate of the fellowship program, Dr. Meaden is Assistant Professor of Emergency Medicine at Rutgers New Jersey Medical School and a Medical Toxicology Consultant for the New Jersey Poison Information and Education System. He is board certified in Emergency Medicine, Medical Toxicology, and Addiction Medicine. Dr. Meaden has a Master of Science degree in molecular and cellular biology. His interests include education in medical toxicology, acute care of the poisoned patient, and chemical agents of war. He is involved with the American College of Medical Toxicology Education Committe, having chaired multiple Annual Scientific Symposia. His research interests include epidemiology and management of opioid overdose, poison centers and toxicosurveillance, and pharmacogenomics.

Jessuca Krueger, MD
Dr. Krueger is an Assistant Professor at Rutgers New Jersey Medical School and is board-certified in Emergency Medicine and Medical Toxicology. Prior to pursuing medicine, Dr. Krueger worked as a research technician in neuroscience. She completed her medical studies at SKMC at Thomas Jefferson University and her residency training at the Albert Einstein Medical Center in Philadelphia in Emergency Medicine. Dr. Krueger completed her Medical Toxicology fellowship in Phoenix with at University of Arizona College of Medicine. She has since developed an interest in pre-clinical research and medical education.

Anita Mudan, MD
Dr. Mudan is an Assistant Professor of Emergency Medicine at Rutgers New Jersey Medical School and a Medical Toxicology consultant with the New Jersey Poison Information and Education System. She is board certified in Emergency Medicine and Medical Toxicology. She completed emergency medicine residency at the Hospital of the University of Pennsylvania and medical toxicology fellowship at the University of California San Francisco. Her interests include the acute care and management of poisoned and substance use patients, medical education in toxicology, and finding “Tox” related snacks for her coworkers to try.

Bruce Ruck, PharmD. DABAT
Dr. Ruck is the Managing Director of New Jersey Poison Information Education System and has been with the Poison Center since 1989. Dr. Ruck is a Diplomat of the American Board of Applied Toxicology and holds adjunct faculty appointments at Rutgers College of Pharmacy and Nursing. Dr. Ruck is active with several professional organizations and works closely with members of the NJ Department of Health and Senior Services. He recently was elected to the Board of Directors of the American Association of Poison Control Centers. In addition to toxicology, his areas of interest include health care professional education, quality assurance and delivery of accurate unbiased information to help in the management of the exposed patient. Dr. Ruck has a special interest in public health as it relates to poison center activities as well as in drug-induced diseases.

Meet the Fellows

Tony Spadaro, MD (2nd year fellow - Combined Addition / Med Tox)
Tony Spadaro attended the University of Pennsylvania where he completed his MD and MPH. He then completed his residency in Emergency Medicine at the Hospital of the University of Pennsylvania. Tony is the first combined fellow in Addiction Medicine and Medical Toxicology. As a resident, his research interests included naloxone distribution in the ED, the impacts of fentanyl on precipitated withdrawl, and emerging novel psychoactives in the drug supply such as xylazine. He is also interested in harm reduction and social emergency medicine. In his free time, he enjoys running long distances, walking his dog, and watching Star Trek.

Ivan Ivanov, MD (2nd year fellow)
Dr. Ivanov completed his emergency medicine residency at South Brooklyn Health (formerly Coney Island Hospital.) He is originally from Chicago and attended medical school at Midwester University - CCOM. He developed a strong interest in toxicology during his intern ICU block when he had several beta blocker overdoses. Hence, he currently enjoys cardiotoxins. Outside of medicine, Ivan enjoys fishing, snowboarding, and travel.

Jason Siebert, MD (1st year fellow)
Jason Siebert is a recent graduate of Jacobi/Montefiore Emergency Medical Residency in the Bronx. He grew up outside Chicago, went to medical school and completed his PhD in immunology at the Medical College of Wisconsin in Milwaukee. His interests in medical toxicology are focused on novel drugs of abuse and toxicological disasters. His favorite snake is the coral snake and his favorite mushroom is amanita muscaria. Outside of medicine Jason enjoys going to concerts. He also enjoys hiking, cooking new recipes, reading and snowboarding. He’s always up for a last-minute trip somewhere new inside or outside of the US.

Nate Sundquist, MD (1st year fellow)
I was born in Augsburg, Germany and moved to Colorado Springs, CO when I was a child. There I went to the University of Colorado and completed my B.S. in Chemistry and became interested in material sciences and started a M.S. in Physical Chemistry. I completed my studies in 2017 and went to Pomona, California at the Western University of Health Sciences for medical school. At the same time, I became a recipient of the U.S. Army HPSP scholarship and started my training in medical school as a 2nd Lieutenant. I became interested in Emergency Medicine and was fortunate to be given a civilian sponsored residency position by the Army to complete my residency training at what is now Jefferson Einstein Hospital Philadelphia and was promoted to Captain. My interactions there with the toxicology staff led me to applying for fellowship positions and the Army granted me a sponsored fellowship position here at Rutgers. My interests outside of work are studying languages, history, cars, soccer and spending time with my fiancé, Bernese mountain dog, Springer spaniel, and American short hair cat.

Paige Williams, MD (1st year fellow - Combined Addition / Med Tox)
Paige Williams attended medical school at the Paul L. Foster School of Medicine in El Paso, TX. She completed her residency at Baylor Scott & White in Temple, TX where her interest in toxicology was sparked through her rotation with the Central Texas Poison Center. Upon graduating from residency, she worked in the community as an emergency physician in San Angelo, TX. Through working in the community, she further developed an interest in the management of substance use disorders. During her free time, she enjoys hiking, trying new restaurants and watching horror films with her cat.

Alumni

• Chris Counts, MD (2025)
• Trevor Cerbini, MD (2024)
• Noah Berland, MD (2023)
• Thuyet-Anh Nguyen, MD (2023)
• Mohammed Jefri, MD (2022)
• David Loughran, MD (2022)
• Christopher Meaden, MD (2021)