Anticholinergic effects olanzapine

The answer is c. (Katzung, pp 485-486.) In addition to its antipsychotic action, olanzapine diminishes emotional bluntness and social withdrawl that are seen in schizophrenic patients, without significant anticholinergic and extrapy rami dal effects. 

We prefer low doses of atypical antipsychotics as a first-line treatment. In this way, the threat of extrapyramidal symptoms is largely avoided without having to use a second anticholinergic medication to offset antipsychotic side effects. Risperidone 0.25-0.5mg/day, olanzapine 2.5mg/day, quetiapine 25mg/day, ziprasidone 20mg/day, or aripiprazole 2.5-5mg/day are reasonable starting doses. The typically higher doses used to treat schizophrenia are usually not necessary. 

Olanzapine is metabolized by several pathways and is therefore unlikely to be affected by concurrent administration of other medications. Because olanzapine does not appear to inhibit any cytochrome P450 enzymes, it should not increase the availability of other medications through inhibition of such enzymes. Additive pharmacodynamic effects are expected if olanzapine is combined with medications that also have anticholinergic, antihistaminic, or aj-adrenergic side effects. 

A meta-analysis of four comparisons of olanzapine and haloperidol showed similar efficacy, with fewer extrapyramidal effects with olanzapine (17). Similar conclusions were reached in another meta-analysis of three randomized, double-bhnd, controlled comparisons of olanzapine and haloperidol (53). Only 15% of olanzapine-treated patients (n = 1620, dosage 5-20 mg/day) needed anticholinergic drugs compared with 49% of those treated with haloperidol (n = 786, dosage 5-20 mg/day). 

Clozapine and olanzapine are the most likely of the atypical agents to cause anticholinergic (anti-muscarinic) effects. They are more likely than other atypicals to cause weight gain (glucose tolerance may be impaired and should be monitored in susceptible individuals) and are second only to quetiapine in their sedative effects. Sexual dysfunction and skin problems are rare with atypical antipsychotics. Risperidone and amisulpride are as likely as classical antipsychotics to raise prolactin concentrations and cause galactorrhoea. 

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