Paroxetine
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image2= Paroxetine-3D-vdW.png | CAS_number = 61869-08-7 | ATC_prefix = N06 | ATC_suffix = AB05 | PubChem = 43815 | DrugBank = APRD00364 | H=20|F=1|N=1|O=3 | molecular_weight = 374.8 | bioavailability = complete absorption from GI, but extensive first-pass-metabolization in the liver; max concentration 4.9 (with meals) to 6.4 hours (fasting) | metabolism = extensive, probable hepatic | elimination_half-life = 24 hours (range 3-65 hours) | excretion = 66% urine, 37% bile | pregnancy_AU = | pregnancy_US = D | pregnancy_category = | legal_status = Rx-only | routes_of_administration = Oral
Paroxetine or paroxetine hydrochloride is a selective serotonin reuptake inhibitor (SSRI) antidepressant. It was released in 1992 by the pharmaceutical company GlaxoSmithKline and has since become one of the most prescribed antidepressants on the market due to its efficacy in treating depression as well as a spectrum of anxiety disorders ranging from panic attacks to phobias.Paroxetine is marketed under the tradenames Paxil in the United States, Canada and Brazil; Seroxat in Austria, Greece, Israel, Poland, Portugal, the UK and China; Aropax in Australia, New Zealand, South Africa and Brazil; Pondera in Brazil; Deroxat in Switzerland and France; Paroxat in Germany, and Cebrilin in Latin AmericaApprovedParoxetine is primarily used to treat the symptoms of depression, obsessive-compulsive disorder (OCD), post-traumatic stress disorder (PTSD), panic disorder, generalized anxiety disorder (GAD),
It was the first (and as of 2002, the only) antidepressant formally approved in the United States for the treatment of social anxiety disorder, causing it to be sometimes referred to (although inaccurately) as an anti-shyness drug.Unapproved/Off-label/InvestigationalParoxetine can also be used in the treatment of premature ejaculation
Paroxetine has been found to significantly reduce the symptoms of diabetic neuropathy
There is also evidence that paroxetine may be effective in the treatment of compulsive gambling
Paroxetine is a phenylpiperidine derivative which is chemically unrelated to the tricyclic or tetracyclic antidepressants. In receptor binding studies, paroxetine did not exhibit significant affinity for the adrenergic (α1, α2, β), dopaminergic, serotonergic (5HT1, 5HT2), or histamine receptors of rat brain membrane. A weak affinity for the muscarinic acetylcholine and noradrenaline receptors was evident. The predominant metabolites of paroxetine are essentially inactive as 5-HT reuptake inhibitors.Paroxetine controlled release contains a Geomatrix™ tablet that controls the absorption of the drug. Clinical studies show that controlled release tablet provides effective symptom relief with a lower number of patients stopping their treatment due to side effects
However, the need for an extended release form of paroxetine has not been established, as the FDA indicated that the half-life for the original Paxil was ideal for once-daily dosing, and that a CR version was not needed.Paroxetine hydrochloride is an odorless, off-white powder, having a melting point range of 120° to 138°C and a solubility of 5.4 mg/mL in water.Paxil / Seroxat (paroxetine) is available in 10, 20, 30, and 40mg tablets.
Paxil CR (paroxetine extended release) is available in 12.5, 25, and 37.5mg tablets.
Paxil, Seroxat and Paxil CR are manufactured by GSK, however a generic is now available under the chemical name paroxetine.General side effects are mostly present during the first 1-4 weeks while the body adapts to the drug. Almost all SSRIs are known to cause either one or more of these symptoms. A person receiving paroxetine treatment may experience a few, all, or none of the following side-effects, and most side-effects will dissappear or lessen with continuted treatment.
*nausea
*drowsiness
*headache
*changes in weight and appetite
*changes in sexual behaviour
*increased feelings of depression and anxiety (initially)
*dry mouth
*constipation
*diarrhea
*rash
*restlessness or akathisia
*itch
*sodium depletion
*changes in urination
*sweating
Individuals experiencing any of the following symptoms should contact their doctor immediately:
* Jaw, neck, and back muscle spasms
* Fever, chills, sore throat, or flu-like symptoms
* Yellowing of the skin or eyes
* Black, tarry stools (this can indicate upper GI bleeding)
Despite these side effects, Paroxetine is effective and generally well-tolerated in adults. Paroxetine is a useful tool in treating major depression, particularly in adults who have not responded to other therapies.Paroxetine users should not discontinue and resume treatment with more than a few days' gap between dosings, as paroxetine decreases in effectiveness if it is stopped for a significant amount of time, and then resumed.While any psycoactive medication (from caffeine to anti-psychotics) can cause withdrawl symptoms upon discontinuation from acute administration, anecdotal evidence suggests that paroxetine has a higher incidence rate and severity of SSRI discontinuation syndrome than other SSRIs and psychoactive medications. For those experiencing extreme and unusual difficulty discontinuing paroxetine, it is recommended that an SSRI with a longer half-life, such as fluoxetine, be administered for approximentally two weeks, then discontinued, to lessen symptoms.Suicidal ideation is a frequently reported experience in those withdrawing from SSRIs. Never seek to withdraw from paroxetine or any other SSRI without supervision.* Paxil Information from Drugs.com
* Detailed Paroxetine Consumer Information: Uses, Precautions, Side Effects from medlibrary.org
* Seroxat must not be used for treatment of children, Royal College of Psychiatrists
* The Secrets of Seroxat, BBC Panorama investigation
* Antidepressant Use in Children Soars Despite Efficacy Doubts, Washington Post, April 18, 2004
* Seroxat and Prozac 'can make people homicidal', The Guardian
* Paroxetine.com - The official paroxetine site
* Quitpaxil.org - Information for persons suffering from Paxil withdrawal syndrome
* Dependence on Antidepressants & Halting SSRIs - protocol for withdrawal
* NIH Expert Panel Report on the reproductive and developmental toxicology of Prozac (Fluoxetine)
* NIH Monograph on the potential human reproductive and developmental effects of Prozac (Fluoxetine)
* "Extroverted like me" A field report by Seth Stevenson
* Paxil Patient Information leaflet, Paxil Patient Information leaflet
* Paxil CR Patient Information leaflet, Paxil CR Patient Information leaflet
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