Tuesday, December 21, 2010

Drug use in Pregnancy- FDA Categories


In view of such events as the thalidomide crisis in the 1960’s when in-utero exposure lead to Phocomelia, and the teratogenic effects of diethylstilbestrol in 1979 US Food and Drug Administration developed strict guidelines regarding drug labeling, use of medications in pregnancy with safety parameters before it was marketed.
FDA classifies various drugs used in pregnancy into five categories, categories A, B, C, D and X. Category A is considered the safest while category X is absolutely contraindicated in pregnancy.

Pregnancy Category A
Adequate and well-controlled human studies have failed to demonstrate a risk to the fetus in the first trimester of pregnancy (and there is no evidence of risk in later trimesters).

Pregnancy Category B
Animal reproduction studies have failed to demonstrate a risk to the fetus and there are no adequate and well-controlled studies in pregnant women OR Animal studies have shown an adverse effect, but adequate and well-controlled studies in pregnant women have failed to demonstrate a risk to the fetus in any trimester.
Pregnancy Category C
Animal reproduction studies have shown an adverse effect on the fetus and there are no adequate and well-controlled studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risks.
Pregnancy Category D
There is positive evidence of human fetal risk based on adverse reaction data from investigational or marketing experience or studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risks.
Pregnancy Category X
Studies in animals or humans have demonstrated fetal abnormalities and/or there is positive evidence of human fetal risk based on adverse reaction data from investigational or marketing experience, and the risks involved in use of the drug in pregnant women clearly outweigh potential benefits.
Source

Sunday, December 19, 2010

Journal Impact Factor

The best evaluation system for the quality of a Journal would involve actually reading all its articles but then the amount of information available is too much, and expanding for this sort of evaluation to carry on.


Here comes the role of Journal Impact Factor.

The Impact factor was devised by Eugene Garfield, the founder of the Institute for Scientific Information, now part of Thomson, a large worldwide US-based publisher.

It is not a perfect tool but is generally considered a good technique for scientific evaluation. For those who have some experience in research publications will know that it is difficult to get an article published in the best of journals, which incidentally also have the highest impact factors.

CALCULATION

The impact factor for a journal is calculated based on a three-year period. It can be viewed as an approximation of the average number of citations in a year, given to those papers in a journal that were published during the two preceding years. For example, the 2003 impact factor for a journal would be calculated as follows:

A = the number of times articles published in 2001-2 were cited in indexed journals during 2003

B = the number of "citable items" (usually articles, reviews, proceedings or notes; not editorials and letters-to-the-Editor) published in 2001-2

2003 impact factor = A/B

(note that the 2003 impact factor was actually published in 2004, because it could not be calculated until all of the 2003 publications had been received.)

A convenient way of thinking about it is that if a journal is cited once for each article published it will have an Impact Factor(IF) of ‘1’ in the expression above.

In the field of psychiatry... Archives of General Psychiatry is the Highest rated in terms of IF. The impact factor of Indian Journal of Psychiatry cannot be calculated as of now as it has been indexed for less than an year.

Sci-Bytes provides ranking and impact factor for selective journals. The list is located here:

http://www.sciencegateway.org/rank/index.html