Anticholinergic effects clozapine

The case in context Clozapine is a newer antipsychotic that can, like other agents in its class, produce antimuscarinic side effects. Although Ms. Doe had not complained of anticholinergic effects prior to beginning treatment with a moderate dose of diphenhydramine, it is likely that the additive anticholinergic effects of clozapine and diphenhydramine resulted in urinary retention. 

Clozapine s anticholinergic effects can cause confusion and delirium as well as sedation and lethargy. The severity of withdrawal psychosis may be due to cholinergic rebound. Clozapine can aggravate or cause hypersalivation, glaucoma, constipation and ileus, and urinary retention (Baldessarini et al., 1991). Weight gain is also a potentially very serious problem. 

Clozapine has a very low incidence of extrapyramidal side effects and very few cases of tardive dyskinesia. It is very sedating and has some anticholinergic and an-tiadrenergic side effects (see Fig. 17-B). Sedation is the most troublesome side effect. Clozapine lowers the seizure threshold and can cause hepatitis. The most serious side effect, however, is a severe blood disorder, aplastic anemia, which has caused several deaths in the United States. These deaths have occurred despite the mandatory weekly monitoring of white blood cell count. Clozapine can cost as much as 10,000 per year because of the need for weekly blood tests, although this cost is offset by reduced hospitalizations. Also, there have been a few sudden deaths associated with clozapine, presumably cardiac in nature. 

Urinary hesitancy and retention is reported with low-potency FGAs and with clozapine. Anticholinergic effects canse smooth mnscle slowing and paralyze the detrusor muscle of the bladder, requiring greater mine volume to evoke muscle contraction. Men with benign prostatic hypertrophy are especiaUy prone to this effect. ... 

Clozapine also has been shown to benefit schizoaffective and bipolar patients with treatment-refractory mania ( 54) patients with Parkinson s disease and those with other neurological disorders with psychoses, such as Huntington s disease. Although clozapine has been shown to be an effective agent in the elderly, its usefulness in this population is limited because of its anticholinergic, sedative, cardiovascular, and potentially toxic effects on the bone marrow ( 55). In a study of 12 elderly female psychotic patients on clozapine (maximal daily dose, 300 mg), for example, five were taken off clozapine because of postural hypotension, one had a nonfatal episode of agranulocytosis, and one had leukopenia ( 56). 

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