Chlorpromazine Benzatropine

Olanzapine versus chlorpromazine In 103 previously treatment-resistant patients with schizophrenia were given a prospective 6-week trial of 10-40 mg/day of haloperidol 84 failed to respond and were randomly assigned to a double-blind, 8-week, fixed-dose trial of either olanzapine 25 mg/day alone (n = 42) or chlorpromazine 1200 mg/day plus benzatropine mesylate 4 mg/day (n = 39) (51). There was no significant... 

In a double-blind study 3 patients given a phenothiazine and benzatropine for the parkinsonian adverse effects, developed an intermittent toxic confusional state (marked disturbance of short-term memory, impaired attention, disorientation, anxiety, visual and auditory hallucinations) with peripheral antimusearinies signs. Similar reactions occurred in 3 elderly patients given imipramine or desipramine, with trihexyphenidyl, and in another man given chlorpromazine, benzatropine and doxepin. ... 

Other studies confirm that trihexyphenidyl and orphenadiine reduce the plasma levels and effects of chlorpromazine. In contrast to these reports, another found that trihexyphenidyl increased chlorpromazine levels by 41% in 20 young schizophrenics, but no clinical change was seen. The levels dropped again over the first 4 weeks of treatment. Some of the beneficial actions of haloperidol on social avoidance behaviour ate lost during concurrent treatment with benzatropine, but cognitive integrative function is unaffected. 

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