ARTICLE DOI: 10.31480/2330-4871/107


Ketamine Hallucination & Dose Limits Rebutted

Barry L Friedberg, M.D.

President, Goldilocks Anesthesia Foundation, USA

*Corresponding author: Barry L Friedberg, M.D., President, Goldilocks Anesthesia Foundation, P.O. Box 10336, Newport Beach, CA 92658, USA, Tel: 949-233-8845; E-mail:

Editor: Renyu Liu, MD, PhD, Associate Professor, Department of Anesthesiology and Critical Care, Perelman School of Medicine at the University of Pennsylvania, Center of Penn Global Health Scholar, Director of Stroke 120 Special Task Force, Chinese Stroke Association, 336 John Morgan Building, 3620 Hamilton Walk, Philadelphia, PA 19104, USA, Phone: 2157461485, Fax: 2153495078, E-mail:

Received: December 05, 2019 | Accepted: December 05, 2019| Published: December 09, 2019

Citation: Friedberg BL. Ketamine Hallucination & Dose Limits Rebutted. Transl Perioper & Pain Med 2020; 7(1):170.

Congratulations to Bohringer, et al. for their recent contribution to the growing literature about opioid free anesthesia (OFA) [1]. Their unreferenced assertion that bolus doses larger than 0.25 mg/kg ketamine should be avoided especially in coronary artery patients for fears of tachycardia and hypertension (i.e. 'adrenergic storm') leading to myocardial ischemia cannot go unchallenged.

Adrenergic storm has been historically reported when ketamine is given as a solo agent. Vinnik used diazepam pretreatment to avoid adrenergic storm [2]. I published hypnotic levels of propofol to prevent hallucinations [3,4]. Over my 26-year OFA career, more than 6,000 propofol ketamine patients received 50 mg bolus after incremental propofol induction (see without adrenergic storm [5]. In Table 2, the authors repeat the ketamine hallucination admonition despite publications with pre-ketamine propofol [3]. Lastly, the absence of any mention of the positive contribution of brain monitoring to OFA was disappointing [6].

I again congratulate the authors on their otherwise fine OFA contribution but must respectfully rebut their ketamine dosage limits and hallucinations.


  1. Bohringer C, Astorga C, Liu H: The benefits of opioid free anesthesia and the precautions necessary when employing it. Transl Periop & Pain Med 2020;2:152-157.
  2. Vinnik CA: An intravenous dissociation technique for outpatient plastic surgery: tranquility in the office surgical facility. Plast Reconstr Surg 1981;67:799-805.
  3. Friedberg BL: Propofol-ketamine technique, dissociative anesthesia for office surgery: a five-year review of 1,264 cases. Aesth Plast Surg 1999;23:70-74.
  4. Friedberg BL: Hypnotic doses of propofol block ketamine induced hallucinations. Plast Reconstr Surg 1993;91:196.
  5. Friedberg BL: Can Friedberg's Triad solve persistent anesthesia problems? Over-Medication, Pain Management, Postoperative Nausea and Vomiting. Plast Reconstr Surg Global Open 2017;5:e1727-1734.
  6. Friedberg BL: How does routine anesthesia care impact today's opioid crisis; the rationale for opioid free anesthesia (OFA). Transl Periop & Pain Med 2018;5:98-100.
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