Tuesday, September 15, 2009

Medication Treatment of Gastroesophageal Reflux Disease (GERD)

Over-the-counter medication is the first line treatment of GERD is with over the counter antacids like aluminum hydroxide (Amphojel, Maalox) or magnesium combinations include Phillips' Milk of Magnesia, Gaviscon and Riopan. Aluminum can cause constipation, and magnesium diarrhea. These compounds work by coating the stomach and provide protection against the corrosive effects of stomach acid. Ulcers need more aggressive treatment, since bleeding from ulcers can be life threatening.

The original medications for the treatment of both GERD and ulcers were the histamine-2 (H2) blockers, like cimetidine (Tagamet), ranitidine (Zantac) and famotidine (Pepcid). These worked by decreasing the amount of acid in the stomach, which promotes healing of ulcers and reduces gastric reflux. Patients with reduced kidney or liver function can develop confusion with H2 blockers. Side effects include diarrhea, dizziness, nausea, and headache. Tagamet can impair sexual function.

In 1998 AstraZenica introduced Prilosec (omeprazole), the first of a new class of medications for GERD called Proton Pump Inhibitors (PPI). PPIs on the market include lansoprazole (Prevacid), pantoprazole (Protonix), rabeprozale (Aciphex), esomeprazole (Nexium), and omeprazole (Prilosec). They act by blocking the H+ (hydrogen) K+ (potassium) ATPase pump in the stomach, which has the effect of decreasing acid secretion in the stomach. The PPIs have been shown to be more effective than placebo in promoting the healing of ulcers and decreasing symptoms of GERD. PPIs lead to a 33% improvement in ulcer healing compared to the older H2 blocker medication, ranitidine. The PPIs decrease acid secretion to a greater degree than H2 blockers, and are more effective in treatment, although they cost more than the older drugs because they are only available by prescription.

PPIs have a low side effect profile, with side effects in less than 5% of patients. The most common side effects are headache, diarrhea, stomach pain, fever, sore throat, and nausea. The diarrhea may be related to suppression of acid formation, which alters the natural bacteria content of the gut. Overall PPIs are fairly safe.

A review of 21 randomised controlled trials of PPIs in patients with proven peptic ulcers showed no effect on mortality, but a reduction in re-bleeding and repeat surgery of about 50%.

There is no evidence that any of the PPIs are superior to one another in efficacy or safety. Since omeprazole (Prilosec) is now available as a generic, it is the cheapest, and therefore recommended PPI.

You have probably seen the man on TV talking about the "purple pill" or Nexium (Esomeprazole magnesium). This particular purple pill is a replacement of the original purple pill, Prilosec. Both should probably be called the green pill because of all the money they have made and continue to make for the manufacturer, AstraZenica. They are both widely popular and equally effective medications. After its introduction in 1998, sales of Prilosec continued to rise year after year until it reached sales of one billion dollars a year in 1995 and peaked at 4 billion dollars a year in 2000 when it was the most popular drug in the world, as reported by National Public Radio (April 18, 2002).

In 2002 AstraZenica convened a team to assess the impact of their blockbuster Prilosec going off patent. In response to the potential revenue loss that generics would cause, they decided to take a variation of the drug (a metabolite) and put it on patent, and then marketed the new version as an improvement on the original. You see, all molecules come in one version, and an identical version that is a "mirror version" (i.e. if you held it up to a mirror it would look the same). In the case of Prilosec, it was a mixture of left and right, but it turned out that the left hand variety worked better. So the company took the left hand version and called it Nexium; they tested a higher dose of the "new" drug against the "old" drug to "prove" that it was better, and sent out an army of sales people to convince doctors that this was the case. Needless to say if you took higher doses of the older Prilosec you would get a regular dose of Nexium, the "purple pill." It was an effective campaign: by 2002 the company had weaned one in six former Prilosec users off of Prilosec and onto Nexium. At $1,500 a year it is much more expensive than the generic versions of Prilosec ($150/year). Why not just take higher doses of Prilosec - it will eventually get your Nexium fix for a lot less money.

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