Treatment of Delirium
The primary consideration in the treatment of delirium is the patient's survival. Delirium can have a mortality rate as high as 25%, so any reversible etiologies should be addressed immediately. For safety, the delirious patient should have a sitter.
Initially, it is important to incorporate supportive interventions do minimize confusion and distress. For example, interpersonal contact is important, as is frequent re-orientation to date and place. Mobility needs to be encouraged as opposed to denied. When possible, patients should be awaken as little as possible at night. Even with supportive changes, pharmacological interventions are often necessary, though dosage ranges for delirium vary according to severity.
Pharmacological considerations
Less potent first-generation antipsychotics have an increased risk of orthostatic hypotension and sedation. The increased anticholinergic activity of first-generation antipsychotics can increase confusion. In particular, phenothiazines (e.g., thorazine, fluphenazine, prochlorperazine, thioridazine, & trifluoperazine) should be avoided because of a greater incidence of anticholinergic and cardiac side effects.
IV Haloperidol
Antipsychotics are the primary psychiatric treatment for the symptoms of delirium. Historically, haloperidol has been the drug of choice for delirium and it can be administered IV. However, IV haloperidol necessitates cardiac monitoring because of an increased risk of QTc prolongation and possible torsade de pointes. IV haloperidol is not a good choice if a patient's baseline QTc > 450 msec. Fortunately, the incidence of torsade de pointes after IV haloperidol administration is relatively low, and has been estimated to be approximately 0.3%. Torsades de pointes related to haloperidol IV tends to occur at doses over 35 mg/day, a rapid (< 6h) infusion, and is preceeded by QTc delays of >500 msec. Although it is not recommended, there are reports of administering from 100-1,000 mg of haloperidol IV in one day.
★ Prior to administering haloperidol IV, some cautions are:
Use caution if a patient has other risk factors for an increased QTc.
Because haloperidol undergoes hepatic metabolism, there isn't a problem using it in patients with renal failure.
Second-generation antipsychotics
More recently, standards of practice have gravitated toward the use of second-generation antipsychotics for delirium. For older or frail patients, risperidone dosages of 0.5 mg twice daily is often adequate, though some patients may require 2-4 mg per day titrated up over a week or so. A double-blind trial of risperidone vs. haloperidol demonstrated equal efficacy in delirium.
Olanzapine can be used in the treatment of delirium, but the incidence of sedation with olanzapine can make it undesirable in some patients. Sedation is also a notable issue with quetiapine. In general, aripiprazole is a less desirable choice because of the comparatively increased incidence of extrapyramidal signs, akathisia, and activation.
Although benzodiazepines have a place in alcohol or benzodiazepine withdrawal, they are not always ideal for the management of delirium. For example, in older patients, benzodiazepines may increase sedation and increase confusion. If benzodiazepines are used in older delirious patients, it is best to reduce the dose if any concomitant antipsychotic, use a low dose of the benzodiazepine, and avoid long-acting benzodiazepines. In all delirious patients, it is best to use benzodiazepines that do not have active metabolites: clonazepam, lorazepam, oxazepam, and temazepam.
Delirium Tremens
In the treatment of delirium tremens, longer-acting benzodiazepines are the drug of choice. Two good choices would be diazepam or chlordiazepoxide (my preference). Lorazepam can be used in the face of end-stage cirrhosis. Unlike an uncomplicated alcohol withdrawal, benzodiazepines for delirium tremens should be given on a regular basis and tapered off over 5-10 days. It would not be unusual for such patients to need up to 12 mg lorazepam, 100 mg diazepam, or 600 mg chlordiazepoxide. Usually the benzodiazepines can be given orally, but if this isn't feasible remember that lorazepam and diazepam can be given IV and diazepam can be given rectally. It is best not to use IM administration in delirium tremens, because the release of the drug is less predictable.