Name and Chemical Formula. Protriptyline (pro-TRIP-till-eene) is a tricyclic antidepressant; sometimes patients with apnea take it as well. Its chemical formula is C18H22N, and it's often sold under the trade name Vivactil.

Purpose. As with most of the tricyclics, protriptyline is generally prescribed only to those patients who have not benefited from the SSRIs or the atypical antidepressants. It exerts only a mild sedative effect; patients who need a sedating antidepressant generally take amitriptyl1ne or doxepin instead.

Side-effects. Protriptyline does inhibit acetylcholine reuptake to an extent, so it can produce the typical side-effects of anticholinergic drugs (dry mouth, constipation or diarrhea, tachycardia or bradycardia, headache, nausea, insomnia, drowsiness, and anxiety).

Contraindications. Protriptyline is usually not prescribed to patients with the following conditions:

Drug Interactions:

Source: A Primer of Drug Action, Robert Julien

Neil is absolutely right; you should be aware of the limitations of everything drug nodes.