Severe anhidrosis and fatal hyperthermia have occurred. Adverse reactions may be anticholinergic or antihistaminic in nature. Dry mouth, blurred vision, nausea, and nervousness may develop. Adjustment of dosage or time of administration sometimes helps to control these reactions. If dry mouth is so severe that there is difficulty in swallowing or speaking, or loss of appetite and weight, reduce dosage, or discontinue temporarily.
Vomiting occurs infrequently.
Nausea unaccompanied by vomiting usually can be disregarded. Slight reduction in dosage may control the nausea and still give sufficient relief of symptoms. Vomiting may be controlled by temporary discontinuation, followed by resumption at a lower dosage. Other adverse effects attributed to benztropine include constipation, numbness of the fingers, listlessness and depression. Occasionally, an allergic reaction, e.g., skin rash, develops.