Q: Ketamine can be given as an intramuscular (IM) injection to an acutely agitated patient?
Ketamine can be given as an IM injection to an acutely agitated patient. It has a relatively same safety profile and works quicker than a benzodiazepine (BZD) or haloperidol. IM dose is double than IV dose i.e., 4 to 6 mg/kg. The onset of action is approximately within 5 minutes and the duration of action is about 10-20 minutes. It can be a good bridging modality for a more stable and longer treatment plan. The dose can be repeated at half of the initial dose if needed. Similarly, the dose should be reduced if a patient has received or receiving any other antipsychotic medication(s).
In ICU, an IV route can be utilized with a 1 to 2 mg/kg dose.
Said that clinician should be prepared for side-effects such as an increase in blood pressure and heart rate as well as nausea and vomiting. Laryngospasm is unlikely but can occur. Ketamine is contraindicated in patients with hallucinations and schizophrenia. It is preferred to avoid in very elderly and cardiac patients.
References:1. Ho JD, Smith SW, Nystrom PC, et al. Successful management of excited delirium syndrome with prehospital ketamine: two case examples. Prehosp Emerg Care 2013; 17:274.