Thalidomina
Páginas: 5 (1132 palabras)
Publicado: 13 de septiembre de 2011
Thalidomide
Thalidomide was sold in a number of countries across the world from 1957 until 1961 when it was withdrawn from the market after being found to be a cause of birth defects in what has been called "one of the biggest medical tragedies of modern times".[4] It is not known exactly how many worldwide victims of the drug there have been, although estimates range from 10,000 to 20,000.[5]Since then thalidomide has been found to be a valuable treatment for a number of medical conditions and it is being prescribed again in a number of countries, although its use remains controversial, including its testing in the developing world.[6][7][8] The thalidomide tragedy led to much stricter testing being required for drugs and pesticides before they can be licensed.[9]
Birth defects
Inthe late 1950s and early 1960s, more than 10,000 children in 46 countries were born with deformities such as phocomelia, as a consequence of thalidomide use.[14] The Australian obstetrician William McBride and the German pediatrician Widukind Lenz suspected a link between birth defects and the drug, and this was proved by Lenz in 1961.[15][16] McBride was later awarded a number of honoursincluding a medal and prize money by the prestigious L'Institut de la Vie in Paris.[17]
In the United Kingdom the drug was licensed in 1958 and, of the approximately 2,000 babies born with defects, 466 survived.[18] The drug was withdrawn in 1961 and in 1968, after a long campaign by The Sunday Times newspaper, a compensation settlement for the UK victims was reached with Distillers CompanyLimited.[19][20] In Germany approximately 2,500 thalidomide babies were born.[16] In some extreme cases, it could kill the patient if there were other diseases or drugs in the body.
The impact in the United States was minimized when pharmacologist and M.D. Frances Oldham Kelsey refusedFood and Drug Administration (FDA) approval for an application from the Richardson-Merrell company to market thalidomide,saying further studies were needed. And although thalidomide was never approved for sale in the United States, millions of tablets had been distributed to physicians during a clinical testing program. It was impossible to know how many pregnant women had been given the drug to help alleviate morning sickness or as a sedative.[21]
Canada was the last country to stop the sales of the drug, in early1962.[22]
In 1962, the United States Congress enacted laws requiring tests for safety during pregnancy before a drug can receive approval for sale in the U.S.[23] Other countries enacted similar legislation, and thalidomide was not prescribed or sold for decades.
In September 2010, as noted in an article titled "The Public’s Quiet Savior From Harmful Medicine", the FDA honored Dr. Kelsey with thefirst Kelsey award. It will be given to an FDA staff member annually. The award came 50 years after Dr. Kelsey, then a new medical officer at the agency, first reviewed the application from the William S. Merrell Company of Cincinnati.[24]
Mechanism
It was soon discovered that only one particular optical isomer of thalidomide caused the teratogenicity. The pair of enantiomers, while mirrorimages of each other, cause different effects,[25] although it is now known that the "safe" isomer can be converted to the teratogenic isomer once in the human body.[16][26](see Teratogenic mechanism).
Thalidomide is racemic – it contains both left- and right-handed isomers in equal amounts. The (R) enantiomer is effective against morning sickness but the (S) is teratogenic. The enantiomers caninterconvert (racemize) in vivo[48] – that is, if a human is given pure (R)-thalidomide or (S)-thalidomide, both isomers will later be found in the serum – therefore, administering only one enantiomer will not prevent the teratogenic effect.
Revived interest
In 1964 Jacob Sheskin, Professor at the Hebrew University of Jerusalem at Hadassah University Hospital (he was also the chief staff and...
Thalidomide was sold in a number of countries across the world from 1957 until 1961 when it was withdrawn from the market after being found to be a cause of birth defects in what has been called "one of the biggest medical tragedies of modern times".[4] It is not known exactly how many worldwide victims of the drug there have been, although estimates range from 10,000 to 20,000.[5]Since then thalidomide has been found to be a valuable treatment for a number of medical conditions and it is being prescribed again in a number of countries, although its use remains controversial, including its testing in the developing world.[6][7][8] The thalidomide tragedy led to much stricter testing being required for drugs and pesticides before they can be licensed.[9]
Birth defects
Inthe late 1950s and early 1960s, more than 10,000 children in 46 countries were born with deformities such as phocomelia, as a consequence of thalidomide use.[14] The Australian obstetrician William McBride and the German pediatrician Widukind Lenz suspected a link between birth defects and the drug, and this was proved by Lenz in 1961.[15][16] McBride was later awarded a number of honoursincluding a medal and prize money by the prestigious L'Institut de la Vie in Paris.[17]
In the United Kingdom the drug was licensed in 1958 and, of the approximately 2,000 babies born with defects, 466 survived.[18] The drug was withdrawn in 1961 and in 1968, after a long campaign by The Sunday Times newspaper, a compensation settlement for the UK victims was reached with Distillers CompanyLimited.[19][20] In Germany approximately 2,500 thalidomide babies were born.[16] In some extreme cases, it could kill the patient if there were other diseases or drugs in the body.
The impact in the United States was minimized when pharmacologist and M.D. Frances Oldham Kelsey refusedFood and Drug Administration (FDA) approval for an application from the Richardson-Merrell company to market thalidomide,saying further studies were needed. And although thalidomide was never approved for sale in the United States, millions of tablets had been distributed to physicians during a clinical testing program. It was impossible to know how many pregnant women had been given the drug to help alleviate morning sickness or as a sedative.[21]
Canada was the last country to stop the sales of the drug, in early1962.[22]
In 1962, the United States Congress enacted laws requiring tests for safety during pregnancy before a drug can receive approval for sale in the U.S.[23] Other countries enacted similar legislation, and thalidomide was not prescribed or sold for decades.
In September 2010, as noted in an article titled "The Public’s Quiet Savior From Harmful Medicine", the FDA honored Dr. Kelsey with thefirst Kelsey award. It will be given to an FDA staff member annually. The award came 50 years after Dr. Kelsey, then a new medical officer at the agency, first reviewed the application from the William S. Merrell Company of Cincinnati.[24]
Mechanism
It was soon discovered that only one particular optical isomer of thalidomide caused the teratogenicity. The pair of enantiomers, while mirrorimages of each other, cause different effects,[25] although it is now known that the "safe" isomer can be converted to the teratogenic isomer once in the human body.[16][26](see Teratogenic mechanism).
Thalidomide is racemic – it contains both left- and right-handed isomers in equal amounts. The (R) enantiomer is effective against morning sickness but the (S) is teratogenic. The enantiomers caninterconvert (racemize) in vivo[48] – that is, if a human is given pure (R)-thalidomide or (S)-thalidomide, both isomers will later be found in the serum – therefore, administering only one enantiomer will not prevent the teratogenic effect.
Revived interest
In 1964 Jacob Sheskin, Professor at the Hebrew University of Jerusalem at Hadassah University Hospital (he was also the chief staff and...
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