Selective serotonin reuptake inhibitors Citalopram Fluoxetine

Selective serotonin reuptake inhibitors Citalopram Fluoxetine Fluvoxamine Indalpine Paroxetine ... 

Selective serotonin reuptake inhibitors (SSRIs) Fluoxetine is the prototype of a group of drugs that selectively inhibit the reuptake of serotonin. AH of them require hepatic metabolism and have half-lives of 18—24 hours. However, fluoxetine forms an active metabolite with a half-life of several days. Other members of this group (eg, sertraline, citalopram, paroxetine), do not form long-acting metabolites. 

SSRIs (Selective serotonin reuptake inhibitors) Citalopram, Escitalopram, Femoxetine, Fluoxetine, Fluvoxamine, Paroxetine, Sertraline... 

Selective serotonine reuptake inhibitor (SSRI) is an abbreviation for the class of antidepressants known as the Selective Serotonin Reuptake Inhibitors. Examples of SSRIs include fluoxetine, paroxetine, citalopram, and sertraline. These drugs selectively inhibit the serotonin transporter thus prolonging the synaptic lifespan of the neurotransmitter serotonin. 

Indeed, 5-HT is also a substrate for the 5-HT transporter, itself an important player in the treatment of depression, and more recently for the whole range of anxiety disorders spectrum (GAD, OCD, social and other phobias, panic and post-traumatic stress disorders). It is the target for SSRIs (selective serotonin reuptake inhibitors) such as fluoxetine, paroxetine, fluvoxamine, and citalopram or the more recent dual reuptake inhibitors (for 5-HT and noradrenaline, also known as SNRIs) such as venlafaxine. Currently, there are efforts to develop triple uptake inhibitors (5-HT, NE, and DA). Further combinations are possible, e.g. SB-649915, a combined 5-HTia, 5-HT1b, 5-HT1d inhibitor/selective serotonin reuptake inhibitor (SSRI), is investigated for the treatment of major depressive disorder. 

The first-line therapeutic options for PMDD include the selective serotonin reuptake inhibitors (SSRIs) such as fluoxetine, fluvoxamine, sertraline, paroxetine, and citalopram. These agents can be given either continuously or only during the luteal phase of the menstrual cycle, i.e., initiated at the time of ovulation and discontinued on the first day of menses. 

Since the introduction of fluoxetine (3) in 1987, a series of selective serotonin reuptake inhibitors (SSRIs) have been discovered that have seen broad application in many facets of mood disorders. These compounds include fluvoxamine (4) which contains a trifluoromethyl group and paroxetine (5) and citalopram (6) which contain 4-fluorophenyl groups [5,6]. 

Other Antidepressants. Antidepressant refinements for the next 30 years primarily consisted of the development of new TCAs. However, in 1988, a novel antidepressant class, the selective serotonin reuptake inhibitors (SSRIs), was introduced in the United States. The chief innovation of the SSRIs was that they afforded the comparable effectiveness of the TCAs with fewer side effects and minimal toxicity. The debut of the SSRIs coincided with the reworking of the nosology of the anxiety disorders in DSM-III and DSM-IV. As a result, the SSRIs have been studied extensively in each of the respective anxiety disorders and in many cases have obtained FDA approval for the treatment of one or more of these anxiety syndromes. The SSRIs currently available in the United States include citalopram (Celexa), escitalo-pram (Lexapro), fluoxetine (Prozac), fluvoxamine (Luvox), paroxetine (Paxil), and sertraline (Zoloft). 

The TCAs were once widely used to treat depression in brain-injured patients, but they have been replaced as first-line treatments by the so-called selective serotonin reuptake inhibitors (SSRIs) including citalopram (Celexa), fluoxetine (Prozac), fluvoxamine (Luvox), paroxetine (Paxil), sertraline (Zoloft), and, most recently. 

Selective serotonin reuptake inhibitors. Currently available selective serotonin reuptake inhibitors (SSRIs) include fluoxetine, paroxetine, sertraline, fluvoxamine, and citalopram. At present, expert opinion does not support the usefulness of these serotonergic compounds in the treatment of core ADHD symptoms (National Institute of Mental Health, 1996). Nevertheless, because of the high rates of comorbidity in ADHD, these compounds are frequently combined with effective anti-ADHD agents (see Combined Pharmacotherapy, below). Since many psychotropics are metabolized by the cytochrome P450 system (Nemeroff et ah, 1996), which in turn can be inhibited by the SSRIs, caution should be exercised when combining agents, such as the TCAs, with SSRIs. 

FIGURE 39.2 Treatment algorithm for pediatric obsessive-compulsive disorder (OCD). In adjusting cognitive behavior therapy (CBT), increase frequency or intensity, or alter the setting or format, e.g., have it be home based or day treatment. CMI, clomipramine DMI, desipramine NT, nortriptyline SSRI, selective serotonin reuptake inhibitor (fluoxetine, fluvoxamine, paroxetine, sertraline, citalopram). 

Selective serotonin reuptake inhibitors (SSRIs) citalopram hydrobromide fluoxetine hydrochloride fluvoxamine maleate... 

Another approach to correct neurotransmission is to inhibit the reuptake of the neurotransmitters into their presvnaptic endings. If the presynaptic reuptake mechanism of a neurotransmitter is blocked then more of the neurotransmitter will stay in the synaptic cleft and be functionally available. Many antidepressant drugs, called reuptake inhibitors , are thought to act via this mechanism. If selective for serotonin they are called selective serotonin reuptake inhibitors (SSRIs, Chapter 1), but if selective for both serotonin and noradrenaline they are called serotonin noradrenaline reuptake inhibitors (SNRIs). Most older antidepressants, such as the tricyclic compounds amitriptyline, imipramine and clomipramine, have little specificity for any of the neurotransmitters fluoxetine, paroxetine, citalopram and a few others are specific for serotonin venlafaxine is a representative of the SNRIs. A more recent mixed-uptake inhibitor is mirtazepine, and some similar compounds are about to be launched. 

Although the efficacy of tricyclic antidepressants in the treatment of unipolar depression is beyond reproach, the side-effect profile of these agents makes them less desirable as first-line therapeutic agents. Introduction of selective serotonin reuptake inhibitors (SSRIs) such as fluoxetine, paroxetine, sertraline, citalopram and fluvoxamine in the past decade has revolutionized the treatment of depression universally. The side-effect profile of SSRIs, such as nausea, diarrhea and sexual dysfunction, is considerably more benign than that of tricyclic drugs. Multiple controlled trials have proven the efficacy of SSRIs vs. placebo (Nemeroff, 1994). Recently, a number of SNRIs (serotonin and noradrenaline reuptake inhibitors) and so-called atypical antidepressants have been marketed that may have additional advantages over SSRIs, such as more rapid onset of action (venlafaxine. mirtazapine) and low sexual side-effect potential ( bupropion, nefazodone). Additionally, it appears that venlafaxine may be more efficacious in cases of treatment-refractory depression (Clerc et al., 1994 Fatemi et al., 1999). Finally, in a recent report (Thase et al., 2001),... 

The selective serotonin reuptake inhibitors (SSRIs) represent a chemically diverse class of agents that have as their primary action the inhibition of the serotonin transporter (SERT) (Figure 30-3). Fluoxetine was introduced in the United States in 1988 and quickly became one of the most commonly prescribed medications in medical practice. The development of fluoxetine emerged out of the search for chemicals that had high affinity for monoamine receptors but lacked the affinity for histamine, acetylcholine, and adrenoceptors that is seen with the tricyclic antidepressants (TCAs). There are currently six available SSRIs, and they are the most common antidepressants in clinical use. In addition to their use in major depression, SSRIs have indications in GAD, PTSD, OCD, panic disorder, PMDD, and bulimia. Fluoxetine, sertraline, and citalopram exist as isomers and are formulated in the racemic forms, whereas paroxetine and fluvoxamine are not optically active. Escitalopram is the S enantiomer of citalopram. As with all antidepressants,... 

Selective serotonin reuptake inhibitors (SSRIs) [P] Fluoxetine and paroxetine inhibit CYP2D6 and decrease metabolism of antidepressants metabolized by this enzyme (eg, desipramine). Citalopram, sertraline, and fluvoxamine are only weak inhibitors of CYP2D6, but fluvoxamine inhibits CYP1A2 and CYP3A4 and thus can inhibit the metabolism of antidepressants metabolized by these enzymes. 

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. 

Selective serotonin reuptake inhibitors (SSRIs) inhibit the neuronal reuptake of serotonin in the central nervous system and have shown mixed efficacy in the treatment of autistic symptoms (Moore et al., 2004). A number of studies have shown reductions in repetitive behaviors, lethargy, inappropriate speech, and improvements in the ability to relate to others, cognition, language improvement with fluoxetine (DeLong et al., 1998 Fatemi et al., 1998 Peral et al., 1999), fluvoxamine (McDougle et al., 1996b), and sertraline (Steingard et al., 1997). However, other studies have shown a lack of response with fluvoxamine (Martin et al., 2003) and citalopram (Couturier and Nicolson, 2002). 

Several studies have examined the interaction between selective serotonin reuptake inhibitors (SSRIs) and P-gp and have shown that not all members of this class of drugs are P-gp substrates. Concentrations of paroxetine and venlafaxine/ but not fluoxetine/ were significantly increased in the brains of mdrla/b (—j—) knockout mice compared to concentrations in the wild-type mice.(100) In cell culture studies/ sertraline/ its metabolite desmethylsertraline/ and paroxetine were shown to be potent inhibitors of P-gp however/ citalopram and venlafaxine were only weak inhibitors (101/ 102). 

Selective serotonin reuptake inhibitors Fluoxetine Fluvoxamine Citalopram, paroxetine, sertraline... 

Since their introduction in the 1980s, selective serotonin reuptake inhibitors (SSRls) such as paroxetine, fluoxetine, and citalopram have enjoyed tremendous clinical and commercial success due to their improved safety profile when compared with first-generation tricyclic antidepressants like imipramine. Nevertheless, they still display several side effects including gastrointestinal distress, anxiety, insomnia, weight gain, and sexual dysfunction. Like other current antidepressants. 

C. Serotonin uptake inhibitors (often called selective serotonin reuptake inhibitors or SSRIs) such as fluoxetine, citalopram, sertraline, paroxetine, flu-voxamine, venlafaxine, and trazodone may interact with each other or with chronic use of an MAO inhibitor (see p 269) to produce the serotonin syndrome (see below and p 21). 

In a study on the effects of maca for sexual dysfunction induced by selective serotonin reuptake inhibitors (SSRI), patients who were stable on an SSRI (patients were taking escitalopram, citalopram, sertraline, venlafexine, fluoxetine, paroxetine, duloxetine, or fluvoxamine) were orally administered 1.5 or 3 g of maca daily for 12 weeks. No adverse effects of maca, including effects on SSRI efficacy, were reported, and patients in the high dose group had a modest improvement in depression (Dording et al. 2008). 

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