Selective serotonin reuptake inhibitors dosing

TABLE 7-17. Selective serotonin reuptake inhibitors dose regimens... 

Dizziness, vertigo, nausea, vomiting, constipation, and lethargy are all relatively common adverse events. These effects are more pronounced for several days after initiation and following upward dose titration. Seizures have been reported rarely the risk is dose-related and appears to increase with concomitant use of antidepressants, such as tricyclic antidepressants or selective serotonin reuptake inhibitors. Tramadol should be avoided in patients receiving monoamine oxidase (MAO) inhibitors because tramadol inhibits the uptake of norepinephrine and serotonin. 

Side effects can also occur quickly after a single dose of a medication. For example, some antidepressants (e.g., selective serotonin reuptake inhibitors) can cause nausea, stomach upset, loose stools, and even diarrhea. Likewise, some anti-psychotics (e.g., haloperidol (Haldol)) can cause unpleasant or painful muscle spasms called dystonias. All of these side effects can occur within minutes or hours of taking a single dose of the medication. These side effects are also a result of the direct effects of the medication in the synapse. 

MAOIs are commonly associated with treatment-emergent sexual dysfunction, including decreased libido, delayed ejaculation, anor-gasmia, and impotence. Some patients become tolerant to this side effect over time, but more often the problem persists unless the dose is reduced or another medication is used to counter the sexual side effects. The treatment of sexual side effects is discussed in the Selective Serotonin Reuptake Inhibitors section earlier in this chapter. 

Rasagiline Inhibits MAO-B selectively, higher doses also inhibit MAO-A Increases dopamine stores in neurons may have neuroprotective effects Parkinson s disease adjunctive to levodopa smooths levodopa response Oral Toxicity interactions may cause serotonin syndrome with meperidine, and theoretically also with selective serotonin reuptake inhibitors, tricyclic antidepressants... 

The depressive phase of manic-depressive disorder often requires concurrent use of an antidepressant drug (see Chapter 30). Tricyclic antidepressant agents have been linked to precipitation of mania, with more rapid cycling of mood swings, although most patients do not show this effect. Selective serotonin reuptake inhibitors are less likely to induce mania but may have limited efficacy. Bupropion has shown some promise but—like tricyclic antidepressants—may induce mania at higher doses. As shown in recent controlled trials, the anticonvulsant lamotrigine is effective for many patients with bipolar depression. For some patients, however, one of the older monoamine oxidase inhibitors may be the antidepressant of choice. Quetiapine and the combination of olanzapine and fluoxetine has been approved for use in bipolar depression. 

Linezolid Prevents bacterial protein synthesis by binding to the 23S ribosomal RNA of 50S subunit Bacteriostatic activity against susceptible bacteria Infections caused by methicillin-resistant staphylococci and vancomycin-resistant enterococci Oral, IV hepatic clearance (half-life 6 h) dosed twice-daily Toxicity Duration-dependent bone marrow suppression, neuropathy, and optic neuritis serotonin-syndrome may occur when coadministered with other serotonergic drugs (eg, selective serotonin reuptake inhibitors)... 

Newer antidepressants (eg, fluoxetine, paroxetine, citalopram, venlafaxine) are mostly selective serotonin reuptake inhibitors and are generally safer than the tricyclic antidepressants and monoamine oxidase inhibitors, although they can 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. The SSRIs may interact with each other or especially with monoamine oxidase inhibitors to cause the serotonin syndrome, characterized by agitation, muscle hyperactivity, and hyperthermia. 

Lundmark J, Bengtsson F, Nordin C et al (2000) Therapeutic drug monitoring of selective serotonin reuptake inhibitors influences clinical dosing strategies and reduces drug costs in depressed elderly patients. Acta Psychiatr Scand 101 354-359... 

Amitriptyline is usually the treatment of choice for neuropathic pain. Some selective serotonin reuptake inhibitors (SSRIs) such as fluoxetine (Prozac ),paroxetine (Paxil ),sertraline (Zoloft ), and clomipramine (Anafranil ) can be used, but they don t appear to be as effective as TCAs. The doses for TCAs in treating neuropathic pain are usually lower than those for treating depression, and the drugs usually start to take effect more quickly in relieving pain than they do in relieving depression. It is interesting that people who suffer from chronic pain often experience symptoms of depression, so TCAs can benefit these people by helping to ease not only their pain but also their depressed mood. 

Reinblatt and Riddle (2006) stated, Selective serotonin reuptake inhibitor (SSRI)-induced apathy is characterized by a lack of motivation that is not a result of sedation or symptoms of depression. In a review of 43 participants in a fluvoxamine pediatric research project, the authors identified two (5%) cases of apathy, one in a 9-year-old and the other in a 16-year-old, neither of whom was depressed. They found that similarities to existing reports included Lack of insight, delayed onset, dose dependency, and reversibility with SSRI dose reduction or discontinuation. ... 

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