Ondansetron chemical structure
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Zofran

Ondansetron is a serotonin 5-HT3 receptor antagonist used mainly to treat nausea and vomiting following chemotherapy. Its effects are thought to be on both peripheral and central nerves. One part is to reduce the activity of the vagus nerve, which is a nerve that activates the vomiting center in the medulla oblongata, the other is a blockage of serotonin receptors in the chemoreceptor trigger zone. It does not have much effect on vomiting due to motion sickness. This drug does not have any effect on dopamine receptors or muscarinic receptors. more...

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Ondansetron is broken down in the liver. It's elimination half-life is about 2-3 hours following i.v. administration in patients with normal liver and kidney functions. The drug is usually administered once, twice or three times daily, depending on the severity of nausea and/or vomiting. Following oral administration, it takes about 1.5-2 hours to reach maximum plasma concentrations. This drug is removed from the body by the liver and kidneys.

It is currently marketed by GlaxoSmithKline under the trade name Zofran; other manufacturers include Cipla Ltd (Emeset), Chemical Works of Gedeon Richter (Emetron), and Zentiva a.s. (Ondemet).

Clinical uses

  • Chemotherapy-induced nausea and vomiting
    • 5-HT3 receptor antagonists are the primary drugs used to treat and prevent chemotherapy-induced nausea and vomiting. Many times they are given intravenously about 30 minutes before beginning therapy.
  • Post-operative and post-radiation nausea and vomiting
  • Is a possible therapy for nausea and vomiting due to acute or chronic medical illness or acute gastroenteritis

Although highly effective, its high cost limits its use to controlling postoperative nausea and vomiting (PONV) and chemotherapy-induced nausea and vomiting (CINV). It is also used off-label to treat hyperemesis gravidarum in pregnant women, but there is no conclusive data available on its safety in pregnancy, especially during the first trimester.

Clinical effect of ondansetron (and other drugs from the same group) can be potentiated by combining it with dexamethasone.

Adverse effects

Ondansetron is a well-tolerated drug with few side effects. Headache, constipation, and dizziness are the most commonly reported side effects associated with its use. There have been no significant drug interactions reported with this drug's use. It is broken down by the liver's cytochrome P450 system and it has little effect on the metabolism of other drugs broken down by this system.

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Pharmaco-fakery
From Pharmaceutical Technology, 12/1/04 by Douglas McCormick

We've been hearing a lot about counterfeit drugs this month, from thought-provoking sessions at the American Association of Pharmaceutical Scientists' annual meeting to headline-grabbing Food and Drug Administration press conferences. The range of deception is wide, from "premature generics" that contain actual active ingredients in correct dosages to gonadotropin masquerading as human growth factor to lethal ersatz vaccines made with antifreeze.

Yet it's still hard to be sure exactly what to think. Call it Tevye's Syndrome: On the one hand, it's not clear that counterfeiting in the United States actually constitutes the public health menace one would expect from all the vociferating. On the other hand, the human cost of those cases that do occur is so appalling that one feels that we must wipe out the problem at almost any cost.

On the one hand, the FDA handled 22 counterfeiting cases in 2003; 22 in 2002; and 20 in 2001. The consistency of these figures, compared with the equally consistent average of 5.5 cases per year in the preceding years, makes the increase in activity look like a change in enforcement emphasis rather than a change in underlying activity. Opponents of reimportation use the threat of counterfeit drugs as a stalking horse, playing off the country's rising xenophobia to hide complex economic and policy issues behind the simpler threat of poison smuggled in by foreign profiteers.

But on the other hand ...

On the other hand, if we don't keep up the pressure on counterfeiting in the United States, we may share the plight of the developing world, where about three quarters of fake drugs are sold, according to the World Health Organization. During a single 1995 meningitis epidemic in Niger, 2500 people died after receiving counterfeit vaccine (received, WHO says, "as a gift from a country which thought they were safe"). Paracetamol cough syrup tainted with diethylene glycol killed 89 Haitians in 1995 and 30 Indian infants in 1998. And in Africa, where malaria kills a million people a year, fakes account for more than half of the antimalarials on the market. WHO estimates that 200,000 people might survive annually if they could receive effective medication.

The known problems in the United States are much smaller, and we tend to trivialize them by connecting the problem mostly with lifestyle drugs--bootleg Viagra peddled to the credulous over the Internet. In fact, counterfeiters in the United States prey upon the most vulnerable, just as they do in the developing countries, with counterfeit statins, under-strength blood growth factors, and mislabeled antiretrovirals.

Last February, the National Association of Boards of Pharmacy issued a "National Specified List of Susceptible Drug Products." Of the 30 drugs on that list *, 23 treat AIDS or cancer, according to a WebMD analysis. So the counterfeiters--lone-wolf grifters and organized crime--target the isolated, the poor, and the desperate.

FDA has just announced that it will open up labeling rules to allow drug-makers to experiment with radio frequency identification (RFID) tags on bulk packaging (see page 17). This is just a part of the much wider attack on counterfeiting that FDA outlined, also last February, in its report Combating Counterfeit Drugs, with a comprehensive timeline of measures for keeping fakes out of the supply chain--and out of consumers' systems.

The FDA's anticounterfeit plan makes it clear that success requires more than technology. It requires--and this will be second nature to drug manufacturers--vigilant attention to systems and procedures.

That comes at a cost, of course. But, despite nagging doubts about some of the sources of the current focus on pharmaco-fakery, that price may well be worth what it buys: a reduction in needless suffering.

* The current entries on NABP's "National Specified List of Susceptible Drug Products" are Combivir, Crixivan, Diflucan, Epivir, Epogen, Gamimune, Gammagard, Immune globulin, Lamisil, Lipitor, Lupron, Neupogen, Nutropin AQ, Panglobulin, Procrit, Retrovir, Risperdal, Rocephin, Serostim, Sustiva, Trizivir, Venoglobulin, Videx, Viracept, Viramune, Zerit, Ziagen, Zocor, Zofran, Zoladex, Zyprexa.

Douglas McCormick is editor in chief of Pharmaceutical Technology. dmccormick@advanstar.com

COPYRIGHT 2004 Advanstar Communications, Inc.
COPYRIGHT 2005 Gale Group

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