Delirium

Administer 0.5-10 mg haloperidol (intramuscularly or intravenously) depending on level of disturbance and likely tolerance (having considered age, physical status, and risk of side effects).
Observe patient for 20-30 minutes. If the patient remains unmanageable but has not had any adverse effects, double the dose and continue monitoring: Repeat the cycle until an acceptable response occurs or side effects occur.
Patient should be manageable not obtunded.
Up to 2 mg of lorazepam may be administered intravenously or intramuscularly every four hours and may be beneficial in allowing a lower dose of antipsychotics to be used in cases in which extrapyramidal side effects occur: Monitor respiratory functions and level of sedation carefully.
Consider administering flumazenil if there is evidence of significant toxicity.
Upper limits on doses have not been clearly established, but up to 100 mg of intravenous haloperidol every 24 hours is generally safe as is up to 60 mg intravenous haloperidol every 24 hours if benzodiazepines are used concomitantly.

Source: BMJ 2001;322:144-149 ( 20 January ) Delirium: optimising management David J Meagher.