Of the generic versions of the medicine Toprol XL (of metoprolol succinate to prolonged release), against the arterial hypertension, could have the contrary effect to the one sought-after. It is what has rapport1 prepared by the independent laboratory American ConsumerLab.com reveals.
ConsumerLab.com is known for his / her / its work of monitoring of the quality of the natural health products (PSN) offered in the trade. The laboratory was interested lately in the generic versions of the Toprol XL, authorized to the United States since the end of 2006. This synthesis of medicine is prescribed to the hypertensive patients and people enduring cardiac arrhythmia and migraines.
After having passed of the medicine of origin to the generic version, several people would have returned an important increase of their arterial tension, of the unrests of the cardiac rhythm and the episodes of migraines. Their state of health would have improved after their return to the medicine of origin.
A deficient process
Two of the generic medicines – made by Eon Labs and Ethex – would not answer to the dissolution of requirements defined by American medical authorities. "It is very preoccupying because the speed and the rate of dissolution of a medicine in the organism can play considerably on his / her / its effects", sustains Tod Cooperman, president of ConsumerLab.com.
These medicines have rather been submitted to the norms established by the manufacturers, but carried the official mention of the United State Pharmacopeia (USP). According to the authors of the report, mention this mistake leads in the health professionals.
Otherwise, these medicines would contain inactive chemical components (other that the metoprolol) that defer those that one recovers in the medicine of origin. He / it is possible that these substances also contribute to the observed effects, one can read in the report.
Another case signalled
In October 2007, ConsumerLab.com returned similar problems about a generic of the antidepressant Wellbutrin XL2 of origin. According to the analysis of their laboratory, the active ingredient of the generic did not free itself appropriately in the organism. following this report, the American medical authorities announced the holding of an investigation to this topic whose results have not been returned again.
According to ConsumerLab.com, the generic medicines are not the subject of clinical tests aiming to ascertain their efficiency and their safety, as it is the case for the origin of medicines. They ask for the Food and Drug Administration (the American equivalent of Health Canada) to inform the public adequately on the generic medicines.
To Canada
Several generic versions of the metoprolol are offered in the pharmacies of Canada, notably under the shape of tablets to prolonged liberation. To Quebec, 445 000 orders of metoprolol to prolonged liberation would have been emitted in 20073.
Canada health did not make a commentary on the report of ConsumerLab.com. According to the federal Ministry, the generic medicines are submitted to studies that permit them to compare to the product of origin. "During these studies, one measures the quantity of the medicine presents in the blood of the participants. Each receives the medicine of origin and the new generic product in two distinct opportunities. One must show that the quantity of the active ingredient absorbed by the organism and the rhythm of absorption is the same for the generic medicine and the product of origin ", explained Health Canada by way of release.
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