Essentially the most significant class of antidepressants marketed recently will probably be the selective serotonin reuptake inhibitors (SSRIs). The six SSRIs featured in the United States are citalopram (Celexa), escitalopram (Lexapro), fluoxetine (Prozac), fluvoxamine (Luvox), paroxetine (Paxil), and sertraline (Zoloft). The primary uses for the SSRIs include unipolar and bipolar major depression and every one of the panic attacks. However, controlled trials also support the by using SSRIs in the remedy for other psychiatric disorders including dysthymia, premenstrual dysphoria, bulimia nervosa, obesity, borderline personality disorder, alcoholism, body pain, and migraine headache.
Among the list of SSRIs, there exists more similarities than differences. Although all SSRI drugs have the same the mechanism of action, each SSRI features a slightly different pharmacological and pharmacokinetic characteristics. This encourages differences on the list of SSRIs throughout their half-lives, clinical activity, side effects, and drug interactions. There are differences between SSRIs that would be clinically significant.
The earliest drug within the SSRI class was Prozac (Fluoxetine), which hit the united states of america market in 1987. Prozac was FDA approved on December 29, 1987. It is manufactured by Eli Lilly and Company.
Zoloft (Sertraline hydrochloride) was your second SSRI to return to market in america, and it also was approved from the FDA on December 30, 1991. Zoloft is manufactured by Pfizer Inc.
Paxil (Paroxetine hydrochloride) was the third SSRI to come back to market in th usa and was approved from the FDA on December 29, 1992. Paxil is manufactured by GlaxoSmithKline.
Luvox (Fluvoxamine maleate) was the next SSRI FDA approved on December 05, 1994. However, currently its marketing status is "Discontinued".
Celexa (Citalopram hydrobromide) was approved by way of the FDA on July 17, 1998. Celexa is manufactured by Forest Pharmaceuticals, Inc.
Lexapro (Escitalopram oxalate) is the newest and most selective of your SSRIs approved from the FDA on August 14, 2002. Lexapro is manufactured by Forest Pharmaceuticals, Inc. Lexapro is known as a cleaner, improved edition of Celexa.
Mechanism of impact
The brain exchanges data with itself utilizing special chemicals called neurotransmitters, for example serotonin and norepinephrine. Neurotransmitters carry signals from a place nerve cell to a new. Low quantities of serotonin and norepinephrine haven t been known to cause depression nonetheless it widely thought that elevation of such chemicals is associated with improvement in mood in depressed people.
All SSRIs possess the same general mechanism of action. SSRIs seem to relieve indicators of depression by blocking the reabsorption (reuptake) of serotonin by certain nerve cells throughout brain. This leaves more serotonin available, which improves neurotransmission (sending of nerve impulses) and improves mood. Sooner or later, the levels of natural serotonin will rise again, as well as in some instances the SSRI can be reduced and withdrawn.
Approved indications and makes use of
SSRIs are actually primarily utilized for handling depression but have been studied for some indications not from depression.
Celexa (Citalopram) is indicated for the remedy for:
depression
Lexapro (Escitalopram) is indicated of the remedy for:
major depressive disorder
generalized depression (GAD)
Paxil (Paroxetine) is indicated for treatment of:
major a depressive condition
obsessive compulsive disorder (OCD)
panic disorder
sad (social anxiety disorder)
generalized depression
posttraumatic stress disorder (PTSD)
Prozac (Fluoxetine) is indicated for your remedy for:
major a depressive condition
obsessive-compulsive disorder
moderate to severe bulimia nervosa
panic disorder
in January 2003, Prozac was approved because of the FDA of the treatment of depression and OCD in children and adolescents who are 7 to 17 years more matured.
Zoloft (Sertraline) is indicated of the remedy for:
major a depressive condition
obsessive-compulsive disorder
panic disorder
posttraumatic stress disorder
premenstrual dysphoric disorder (PMDD) in grown-ups (newest indication)
social anxiety disorder
Performance
Clinical trials comparing an SSRI with another SSRI show that drugs in this class are equally efficacious. Each SSRI produces approximately a 60% overall response rate (ie, a minimum of a 50% lowering of symptoms because of treatment).
Negative symptoms & unwanted side effects
While SSRIs never appear to can be found in overall tolerability, the reported incidences of specific negative effects vary. Adverse effects that patients experience are generally mild to moderate and don t require dose reductions or discontinuation. SSRIs possess the following adverse effects:
Nausea. By far the most coomon symptom accociated with by using SSRIs is nausea. Paroxetine and sertraline are actually involved with a little bit more cases of nausea.
Erectile dysfunction. Depression itself could bring about ed and all SSRIs have been linked to ed during therapy in men and women. There can be lesser detrimental effect on sexual function by fluoxetine when compared with other agents. Citalopram continues to be associated with the loss of fat from the body libido. Paroxetine can increase the risk for highest rate of sexual dysfunction.
Anticholinergic effects. Paroxetine causes a higher rate of anticholinergic effects, similar to dry mouth, constipation, and cognitive disruption, when compared to other SSRIs. These effects may be particularly difficult to tolerate for elderly or concomitantly medically ill patients.
Weight. The SSRIs vary in their effect on the load. Sertraline is often connected with a small degree of weight reduction throughout acute phase of treatment, whereas paroxetine could cause weight gain after long-term treatment. Fluoxetine contains the most potent appetite-suppressing effects throughout short term and produces a greater degree of weight reduction than paroxetine, sertraline, citalopram, or escitalopram.
Diarrhea. Sertraline and fluoxetine become more frequently linked to diarrhea, paroxetine consists of a lower incidence.
Anxiety, agitation, insomnia. Fluoxetine has long been connected with highest rate of tension and agitation. Escitalopram and paroxatine are more unlikely that to cause insomnia than fluoxetine and sertraline.
Lack of saliva. Citalopram and paroxetine will likely cause sandpaper throat than escitalopram and fluoxetine.
Drowsiness, fatigue. Paroxetine has been involved with highest rate of drowsiness, somnolence in comparison with other SSRIs.
Headache. Sertraline and fluoxetine are associated with advanced level of headache.
Regularly, antidepressants might be associated with worsening problems of depression or suicidal thoughts or behavior, particularly at the beginning of treatment or if you improve your dosage. Be sure to confer with your doctor about any changes in your own symptoms. You may need more careful monitoring at the beginning of treatment or at the change in treatment, you even may require to halt the medication in case your symptoms worsen.
Pharmacokinetics
A number of the key differences among SSRIs are due to differences inside their pharmacokinetic properties. The only pharmacokinetic parameters shared by each of the SSRIs is because are relatively slowly, but completely, absorbed from the gut. They differ with regard with their protein binding, metabolism, half-lives, in the event that they have linear or nonlinear pharmacokinetics, in the event that they have active metabolites.
Half-life
The half-life of a drug is the time needed to achieve steady-state plasma concentrations (i.e., to metabolize half the dose and lower blood concentrations by 50%). Half-life can be used to estimate what amount of time it involves clear a drug coming from the body after treatment is discontinued.
Fluoxetine is special for it's long half-life along with the long half-life of their active metabolite norfluoxetine. Fluoxetine features a half-life of 4-6 days along with its active metabolite, norfluoxetine, has a half-life of 4-16 days. As compared, citalopram, escitalopram, paroxetine, and sertraline have shorter half-lives within the variations of 20-35 hours, and steady-state concentrations (and therapeutic effect) are reached much more rapidly. The long half-life of fluoxetine may blunt the results of missed doses or treatment discontinuation and also makes it simpler to discontinue than any one of the other SSRIs. However, fluoxetine requires a much longer washout period than the other SSRIs (several weeks), particularly when switching to monoamine oxidase inhibitors (MAOIs) or TCA.
Antidepressants with relatively short half-lives are desirable for individuals with multiple comorbidities and opulent, multiple-drug regimens mainly because they enable once-daily dosing. A short half-life enables physicians to exchange more rapidly and safely to an alternative antidepressant if treatment fails or if unfavorable drug reactions occur.
Linear and nonlinear pharmacokinetic.
One of the important differences to note among the list of SSRIs is whether their pharmacokinetic properties are linear or nonlinear.
Citalopram, escitalopram and sertraline show linear and dose-proportional pharmacokinetics. Plasma concentrations of such drugs are proportional into the daily dose administered and, therefore, predictable. On the flip side, fluvoxamine, fluoxetine and paroxetine have nonlinear pharmacokinetics. Higher doses may produce much greater increases in plasma drug concentrations than would otherwise be expected. Thus, increasing the dose of paroxetine or fluoxetine can result in disproportionate and unpredictable increases in plasma levels, half-lives, and negative effects. Titration of fluoxetine and paroxetine doses may therefore be more difficult than with citalopram, escitalopram and sertraline.
Drug Interactivity
The interaction between monoamine oxidase inhibitors (MAOIs) and SSRIs is the main drug interaction limiting SSRI use. This combination may lead towards the development of a hyperserotonergic syndrome being inclusive of excitement, diaphoresis, rigidity, hyperthermia, tachycardia, hypertension, and possibly death. The severity of this interaction necessitates at the very least 5 week washout when switching a private from fluoxetine to an MAOI to allow complete elimination of many fluoxetine. At least 14 days should really be allowed after stopping citalopram, escitalopram, paroxetine or sertraline before you begin an MAOI. This difference in washout time between fluoxetine and citalopram, escitalopram, paroxetine and sertraline when switching from an SSRI to an MAOI is one of the key differences between SSRIs.
Author Resource:-
Citalopram, escitalopram and sertraline Sertraline side effects have the lowest potential for drug interactions among the many SSRIs. Citalopram ought to be avoided in patients about to take overdoses. Sertraline would be side effects of Nexiumpreferable for cardiac patients taking beta blockers or type IC antiarrhythmic agents.
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