Tricyclic antidepressants are rarely used because of their unfavorable side effect profiles; however, they may be used for certain indications such as refractory depression. Thus, it is important to know the most common side effects. Most of the side effects of tricyclic antidepressants come because they block muscarinic anticholinergic receptors and alpha-1 adrenergic receptors. Muscarinic receptor blockade causes dry mouth, constipation, blurred vision, and tachycardia. Adrenergic receptor blockade may cause orthostatic hypotension. Headache and loose stools/diarrhea are not associated with tricyclic antidepressants.