In New Zealand, more than 800 people have complained that a recently reformulated version of Glaxo’s Eltroxin thyroid treatment made them sick or is simply ineffective. Some experts, however, say the flood of reported reactions may actually be psychological, rather than physiological, according to The National Business Review.

At issue is bioequivalency. Brand-name drugmakers sometimes fend off generic competition by charging that a copycat version lacks bioequivalency, another way of saying the generic is absorbed differently in the body. Medsafe, the New Zealand regulator, issued a statement earlier this summer insisting the new version met “bioequivlence criteria,” although is refusing to release Glaxo’s bioequivalency study (see here).

For its part, Glaxo says the reformulation resulted from shifting manufacturing locations from Canada to Germany, and acknowledges “an increase in adverse event reports is not uncommon when patients are placed on a new or reformulated product.” (Look here). Pfizer ran into similar problems recently after reformulating its Dilantin epilepsy drug.

However, Medsafe cites media coverage for the increase in side effect reports. Officials noted Glaxo began supplying the new formulation in July 2007, and until May of this year, there were only about 30 reports of side effects filed to the Centre for Adverse Reactions Monitoring, according to the paper. But when the numbers hit 43 in June, the reactions were publicized, triggering media publicity, and now CARM had reports of 810 reactions from the 70,000 patients taking the drug.

“That increases every time a news item runs on it,” Stewart Jessamine, Medsafe’s group manager, tells the paper. “There is some link between media coverage, and patients either identifying themselves as being potentially affected or coming to the realisation that they have been affected by the product, for whatever reason they care to give.”

Side effects “are routinely seen when patients swap brands of thyroxine but what is unusual about the New Zealand experience is that we are seeing so many reports,” Jessamine continues. But asked to what extent the increase in reports involved an element of “mass hysteria”, he says in about half of the cases, symptoms could be explained by poorer absorption of the new formulation.

“To some extent, it’s immaterial whether this is due to a physical cause…or whether its psychological,” he adds. “There are undoubtedly some people who do need an alternate brand.”

To that end, government agencies are looking at two applications to sell and subsidize other brands of the thyroid drug. Abbott Laboratories has an application being evaluated, and a second company, Goldshield Healthcare NZ is expected to file an application by the end of the month, the paper writes.