Hello. This is Dr. Scott Irwin, Chief of Psychiatry and Psychosocial Services at San Diego Hospice and The Institute for Palliative Medicine. Today I’d like to talk to you about what I call an “agitation code.” Agitation is highly distressing for patients, families, and staff members. We want to get it under control quickly. In the setting of reversible delirium, antipsychotics are the gold standard. I’d like to talk today about using antipsychotics to get agitation under control quickly.
The way we think of agitation is as a breakthrough symptom, just like pain, and so we want to dose medications like we do for pain. Most antipsychotics follow first-order kinetics. They also have a time to maximum concentration (Cmax) in the blood.
The single biggest mistake that people make is dosing medications on the half-life for symptoms that are out of control. If you have a symptom that is out of control, like pain or agitation, and the medication is not working at the time of maximum concentration, then it’s not going to work past that time. What you want to do is dose breakthrough medications on the time to Cmax and schedule routine doses on the time to half-life.
It turns out that for most antipsychotics, 24 hours is the half-life, and time to Cmax for medications [that follow first-order kinetics] is actually dependent on route. So, for IV medications it’s 15 minutes, for sub-Q or IM it’s 30 minutes, and for PO (oral) medications it’s 60 minutes. These are rough approximations, but they’re safe approximations that work well clinically.
For something like haloperidol, which is the gold standard for agitation in the context of reversible delirium, you can usually start at 0.5 mg or, if you wanted, 1 mg. If we’re going to give this SQ, that would be [a dose] every 30 minutes. If you gave it orally it would be every 60 minutes, as needed for agitation. I like to add something else to the physician order and that is “If not effective in 3 doses call MD.” The reason I do this is because if it’s not working in 3 doses (that’s an hour and a half that this patient has been distressed) then I want to know about it. I either have the wrong drug, the wrong diagnosis, or the wrong dose. This [dose of haloperidol] is well within safety measures. You can use up to 100 mg of haloperidol a day. Typically, we don’t see the need to go over 10 mg a day with most of our patients, but you need to reevaluate where you’re going.
For more moderate or severe agitation, you could actually double the dose every time to Cmax. So for SQ you could start at 0.5 mg, then give 1 mg, then 2 mg, and then 4 mg [every 30 minutes]. Or if you were giving it orally it would be the same thing but you would give the dose every hour instead of every 30 minutes.
For extremely severe agitation, where the safety of the patient, staff, or family is at risk, then you might want to use much stronger medications to get agitation under control immediately and then figure out what the best course of action is. For example, you could add 1 or 2 mg of lorazepam to the haloperidol with 50 or 100 mg of Benadryl as well, and then again repeat it on the time to Cmax until the agitation is under control.
Once you figure out how many doses you needed to get the agitation under control you add those up and dose them on the half-life so that the scheduled total dose needed for control over 24 hours is dosed divided on the half-life, which for most antipsychotics is 24 hours. For example, if you needed 3 mg to get this patient’s agitation under control, you would schedule 3 mg every 24 hours, plus the PRN dose for any breakthrough symptoms. If the person continues to need more and more breakthrough doses you would add this to the scheduled dose. Again, agitation is highly distressing for all those involved and we want to get it under control quickly. These are the basics of how to do that.
Thank you for listening. This is Dr. Scott Irwin, Chief of Psychiatry and Psychosocial Services at San Diego Hospice and The Institute for Palliative Medicine.