Citalopram Monoamine oxidase inhibitors

Citalopram is a selective serotonin re-uptoke inhibitor (SSRI). These tend to have fewer ontimuscarinic effects than tricyclic antidepressant (TCA) drugs, such as dry mouth and constipation however, SSRIs tend to cause gastrointestinal effects, such as nausea and vomiting. MAOIs are monoamine oxidase inhibitors. 

Newer antidepressants (eg, fluoxetine, paroxetine, citalopram, venlafaxine) are mostly SSRIs and are generally safer than the tricyclic antidepressants and monoamine oxidase inhibitors, although they can cause seizures. Bupropion (not an SSRI) has caused seizures even in therapeutic doses. Some antidepressants have been associated with QT prolongation and torsade de pointes arrhythmia. SSRIs may interact with each other or especially with monoamine oxidase inhibitors to cause the serotonin syndrome, characterized by agitation, muscle hyperactivity, and hyperthermia (see Chapter 16). 

All SSRIs have common 5-HT agonistic effects and because of this, SSRIs have common interactions and side effects. SSRIs are potent inhibitors of serotonin reuptake by CNS neurons and may interact with other drugs such as monoamine oxidase inhibitors (MAOIs) or circumstances which cause serotonin release. A minimum 2 weeks wash-out period should be observed between stopping a MAOI and starting an SSRI. Conversely, a MAOI should not be started for at least 1 week after an SSRI has been stopped, 5 weeks after fluoxetine, and 2 weeks for paroxetine and sertraline. Escitalopram and citalopram are hypersensitive to each other. 

The bulk of literature examining antidepressant use in AD is made up of case reports and uncontrolled studies. Most of these report a favorable response to antidepressants, but several placebo-controlled trials have demonstrated mixed results. Of the antidepressants studied, citalopram, sertraline, clomipramine, and moclobe-mide (a monoamine oxidase inhibitor not marketed in the U.S.) were considered efficacious in at least one study but fluoxetine and imipramine were no better than placebo. It should be noted that citalopram and sertraline have both been studied in other placebo-controlled trials in this population with no difference over placebo. ... 

Antidepressants can be crudely divided into three classes the monoamine oxidase inhibitors (MAOIs), the tricylic antidepressants (TCAs) and related compounds, and the selective serotonin reuptake inhibitors (SSRIs). HPLC-ED did not feature in a review of methods for five leading SSRIs citalopram, fluoxetine, fluvoxa-mine, paroxetine and sertraline. More recently, Clement et measured venlafaxine (Figure 6.17) and 0-desmethylvenlafaxine by HPLC with coulometric... 

Many noncyclic antidepressants are now available, including trazodone (Desyrel l), nefazodone (Serzone ), fluoxetine (Prozac ), sertraline (Zolotf ), citalopram (Celexa ), escitalopram (Lexapro ), paroxetine (Paxil ), tluvoxamine (Luvox ), venlafaxine (Effexor ), and bupropion (Wellbutrin ). Bupropion is also marketed under the brand name Zyban tor smoking cessation. Mirtazapine (Remeron ), a tetracyclic antidepressant, has recently become available. In general, these drugs are much less toxic than the tricyclic antidepressants (see p 90) and the monoamine oxidase (MAO) inhibitors (p 269), although serious effects such as seizures and hypotension occasionally occur. Noncyclic and tricyclic antidepressants are described in Table 11-7. 

---