Final answer:
The common adverse effect of amitriptyline (Elavil), a tricyclic antidepressant, is dry mouth. This side effect is part of the anticholinergic effects associated with this class of medication. So, the correct option is
2. Dry mouth
Step-by-step explanation:
The common adverse effect of the tricyclic antidepressant amitriptyline (Elavil) is dry mouth.
Amitriptyline is known for its anticholinergic side effects which include dry mouth, blurred vision, constipation, urinary retention, and sometimes dizziness due to orthostatic hypotension.
Among these side effects, dry mouth is often reported by patients as a disturbing and frequently experienced effect.
This tricyclic antidepressant is used to treat major depression and is not recommended for use on an "as-needed" basis because its therapeutic effects usually appear after continuous use for two to three weeks.
Therefore, the correct option is 2. Dry mouth