Haloperidol is a typical butyrophenone type antipsychotic that exhibits high affinity dopamine D 2 receptor antagonism and slow receptor dissociation kinetics. [41] It has effects similar to the phenothiazines . [17] 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. [42] 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 .

My husband – age 79 – is a diabetic and has a-fib heart problems, plus his legs are very weak and he has trouble walking. he has been in the hospital for 1 week, going thru many tests, lung tests, heart tests and such. He has an abcess tooth and it was a several days before it could be taken care of. he was given anitbiotics for the infection and a vicadin sub medication for the pain in the tooth area. He had the tooth taken care of, but then ended up in ER due to his sugar falling and his low BP. He was a bit confused at home after taking the Vicadin – and now he is showing signs of Sundowners at the hospital. he is off the Vicadin and his BP and sugar is controlled. Will his sundowners get better or can i expect it to continue? His father developed dimentia at about 82 years of age.