Tolerability and patient compliance

Currently available antidepressants interact with several types of receptor s, which may explain both wanted and unwanted effects of these drugs. These effects are different and distinctive, and knowledge about them may help c linicians understand differences between compounds in terms of their tolera bility profiles. Given roughly comparable efficacy, tolerability profile is the critical determinant in selecting an antidepressant medication for a p articular patient. In addition, tolerability is inseparably linked to patie nt compliance, both in acute and long-term treatment, and ultimately to ove rall success of treatment. Refinement in pharmacologic profiles of all newl y introduced antidepressants resulted in overall advantages in tolerability in comparison with older tricyclic compounds. However, differences in rece ptor interactions between antidepressants are directly reflected in tolerab ility (adverse event) profiles. Among new antidepressants, mirtazapine and the selective serotonin reuptake inhibitors share favorable overall tolerab ility and safety, especially with respect to low premature termination rate s because of adverse events, cardiac safety, and safety in overdose. Howeve r, the different pharmacologic profile of mirtazapine is reflected in its d ifferent tolerability profile. Because of interactions with the histamine ( H-1) receptor, mirtazapine may be related to transient initial somnolence a nd weight gain in some patients. Its serotonin-2 (5-HT2)-blocking propertie s may account for lack of sexual dysfunction, insomnia, nervousness, and ag itation. Mirtazapine's 5-HT3-blocking properties are unique among all curre ntly available antidepressants and may account for lack of gastrointestinal adverse events.