Paroxetine (paroxetine hydrochloride; trade names Paxil® (United States), Seroxat® (UK), Aropax® (Australia)) is an antidepressant of the selective serotonin reuptake inhibitor (SSRI) type. It was released onto the market in 1992 by the pharmaceutical company GlaxoSmithKline and has since become one of the most prescribed antidepressants on the market. It is the second most prescribed anti-depressant in the UK. It is now the subject of a fraud case in the United States due to allegations that GlaxoSmithKline suppressed research indicating that the drug caused young people to become suicidal.

Like some other antidepressants, it is also prescribed in the treatment of anxiety disorders. 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.

Addiction Potential

The manufacturers claim it is impossible to become addicted to paroxetine. Other campaigners disagree. The medical community generally considers that withdrawal symptoms are not enough to regard a drug as addictive; it has to leave the user needing more and more in order to gain the same desired effect. That's not the case with Paroxetine, as the body does not become tolerant to Parexotine's positive effects. Note, however, that addiction is generally also an extremely debated issue, although no drug is generally considered to be addictive that does not have both withdrawal symptoms and tolerance.

Recent studies have found that the drug is relatively ineffective in children, and that they are prone to becoming suicidal when first given it.

Side Effects

A growing body of anecdotal evidence has raised concerns about some of its side effects.

Although the manufacturers say there is no reliable clinical evidence that the drug can cause violence or aggression, the company was sued in the US after Donald Schell killed his wife, daughter and grandchild after two days on the drug. During the investigation of the clinical records, it was reported that although paroxetine is safe and effective most of the time, in a minority of cases the drug can cause unpredictable side effects, such as wild mood swings or suicidal thoughts.

However, in June 2004 GlaxoSmithKline were again fighting a lawsuit over the drug due to allegations of fraud. The lawsuit alleges that five studies conducted by GSK between 1998 and 2002 suggested that the drug had little more effect than a placebo and increased suicidal tendencies.

Common side effects include:

• drowsiness
• sleepiness
• nausea
• upset stomach
• dry mouth
• constipation
• diarrhea
• decrease of sexual desire
• delayed orgasm or anorgasmia
• rash
• itch
• changes in urination

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

Withdrawal Symptoms

There is a growing amount of personal and anecdotal accounts of withdrawal symptoms from Paroxetine. See, for example, [1] or [2]

Chemistry

Paroxetine is chemically identified as (Immediate-Release Tablets / Oral Suspension:) (-)-trans-4R-(4-fluorophenyl)-3S-[(3,4-methylenedioxyphenoxy) methyl]piperidine hydrochloride hemihydrate, or (Controlled-Release Tablets:) (-)-(3S,4R)-4-[(p-fluorophenyl)-3-[(3,4-methylenedioxy)phenoxy]methyl] piperidine hydrochloride hemihydrate. Its empirical formula is C₁₉H₂₀FNO₃, with a molecular weight of 374.8 (329.3703 as free base).

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.

Pharmacology

Paroxetine is a potent and selective serotonin (5-hydroxytryptamine, 5-HT) reuptake inhibitor (SSRI). This activity of the drug on brain neurons is thought to be responsible for its antidepressant effects.

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 (alpha(1), alpha(2), beta), dopaminergic , serotonergic (5HT(1), 5HT(2)), or histaminergic receptors of rat brain membrane. A weak affinity for the muscarinic acetylcholine receptor was evident. The predominant metabolites of paroxetine are essentially inactive as 5-HT reuptake inhibitors.

External links

• Press Release - Seroxat must not be used for treatment of children
• Press Release - Seroxat must not be used for treatment of children .pdf version
• BBC Panorama investigation, The Secrets of Seroxat
• Paroxetine.com - The official paroxetine site
• Paxil feedback
• Antidepressant Use in Children Soars Despite Efficacy Doubts
• Seroxat User Group - A support group for those suffering adverse effects of the drug
• paxilprogress : Paxil and Paxil Withdrawal Information
• Glaxo faces drug fraud lawsuit - The Guardian - June 2004
  • Follow-up story: Glaxo changes tack after Spitzer assault - The Guardian - June 2004
• Seroxat and Prozac 'can make people homicidal' - The Guardian - September 2004