The influence of renal impairment on the pharmacokinetics of haloperidol has not been evaluated. About one-third of a haloperidol dose is excreted in urine, mostly as metabolites. Less than 3% of administered haloperidol is eliminated unchanged in the urine. Haloperidol metabolites are not considered to make a significant contribution to its activity, although for the reduced metabolite of haloperidol, back-conversion to haloperidol cannot be fully ruled out. Even though impairment of renal function is not expected to affect haloperidol elimination to a clinically relevant extent, caution is advised in patients with renal impairment, and especially those with severe impairment, due to the long half-life of haloperidol and its reduced metabolite, and the possibility of accumulation (see section ).
-Initial dose: to 10 mg orally in divided doses every 6 to 8 hours
-Maintenance dose: 1 to 5 mg/day
-Maximum dose: Up to 40 mg/day
-Maintenance doses may be given as single daily doses.
-Many patients achieve therapeutic effect with doses of less than 20 mg. Patients who are severely disturbed or inadequately controlled may require a dose of up to 40 mg/day.
Fluphenazine Decanoate for Injection:
-Initial dose: to 25 mg deep IM injection into the gluteal region
-Maintenance dose: to 100 mg IM, usually every 3 to 4 weeks
-Maximum dose: 100 mg/injection
Fluphenazine HCl for Injection:
-Initial dose: to 10 mg IM, given as divided doses every 6 to 8 hours
-Maximum dose: Up to 10 mg/day
-Patients may switch from Fluphenazine HCl for Injection to oral formulations when symptoms are controlled. The dose of an oral formulation is approximately 2 to 3 times the dose of fluphenazine HCl for injection.
-Fluphenazine decanoate for injection may be given subcutaneously.
-Management of manifestations of schizophrenia
-Management of patients requiring prolonged parenteral neuroleptic therapy (., patients with chronic schizophrenia)
Haloperidol is a typical butyrophenone type antipsychotic that exhibits high affinity dopamine D 2 receptor antagonism and slow receptor dissociation kinetics.  It has effects similar to the phenothiazines .  The drug binds preferentially to D 2 and α 1 receptors at low dose (ED 50 = and mg/kg, respectively), and 5-HT 2 receptors at a higher dose (ED 50 = mg/kg). Given that antagonism of D 2 receptors is more beneficial on the positive symptoms of schizophrenia and antagonism of 5-HT 2 receptors on the negative symptoms, this characteristic underlies haloperidol's greater effect on delusions, hallucinations and other manifestations of psychosis.  Haloperidol's negligible affinity for histamine H 1 receptors and muscarinic M 1 acetylcholine receptors yields an antipsychotic with a lower incidence of sedation, weight gain, and orthostatic hypotension though having higher rates of treatment emergent extrapyramidal symptoms .