Clarification of Anticholinergic Effects of Quetiapine

Letter to the Editor

Sir: In Table 1 of the article by Kumar and Brecher the muscarinic receptor binding affinity shown for quetiapine is not supported by the pharmacologic and clinical properties of quetiapine and may mislead the readers regarding the anticholinergic effects of quetiapine. The reference used to support the affinity for the muscarinic receptor (rated as "+++," or "moderate," in Table 1) was taken from Pickar but this value has previously been refuted by Goldstein. It is again important to set the record straight, in particular because their article deals with elderly patients who are especially sensitive to the distressing adverse effects resulting from blockade of the muscarinic receptor.