Submitted by Lauri Fennell
![keepingup](https://webarchive.library.unt.edu/eot2008/20090515041258im_/http://nnlm.gov/ner/newsletter/newsimages/keepingup.jpg)
PubMed is constantly updated with improvements and changes. Besides the Technical Bulletin there are many tutorials and training resources.
I recently watched the recorded version of the Chemicals and Drugs in Pubmed webcast—twice actually. You know how you catch more the second time around? It is definitely true in this case. Did any of you happen to catch it? This search clinic was originally presented on August 23, 2007 (before I was at NN/LM).
It was recorded so it can be viewed at any time. I highly recommend it.
Search Clinic: Chemicals and Drugs in Pubmed
http://www.nlm.nih.gov/bsd/disted/clinics/chem.html
In addition to watching the recorded clinic, you can read the transcript and/or the questions and answers section.
Here are some of the highlights:
First I found it helpful to have the differences of a few of the subheadings used for chemicals and drugs explained, specifically toxicity, poisoning and adverse effects.
Toxicity: studies designed to determine ill effects of a substance (usually animal studies)
Poisoning: life threatening—whether by medication error, accidental or otherwise
Adverse effects: choosing this subheading will include both toxicity and poisoning—includes side effects and complications of accepted doses
Detailed definitions for these terms when used as subheadings can be found by searching for each term in the MeSH database.
Further explanation about substance names, pharmacological action and when to use the MeSH tag was also very helpful.
Substance names: chemicals and drugs are not always indexed with a MeSH heading. Instead they may be indexed under a substance name. If this is the case the substance will be mapped to the MeSH heading appropriate for that substance.
Here’s an example:
When searching in MeSH for zetia (recently in the news) you will get this record:
![](https://webarchive.library.unt.edu/eot2008/20090515041258im_/http://nnlm.gov/ner/newsletter/newsimages/entrez_mesh.gif)
![](https://webarchive.library.unt.edu/eot2008/20090515041258im_/http://nnlm.gov/ner/newsletter/newsimages/zetia.jpg)
Ezetimibe is the substance name for Zetia. You find the drug brand names in the list for entry terms. This substance is mapped to Azetidines as a MeSH term. The pharmacological action assigned to it is anticholesteremic agents.
The Questions and Answers section was very helpful. Some questions were answered later with additional NLM staff input.
http://www.nlm.nih.gov/bsd/disted/clinics/qa.html
Some additional items that will become clearer after watching the webcast:
- Check the details box to see if the chemical/substance name you used is mapped to a MeSH or Substance Name. If it is not, use the preview/index feature to search for the name to see if there are alternatives you can use
- Using the [pa] versus the [mh] tag: using [pa] searches the full list of substances designated with that pharmacological action. Using [mh] searches for the action as a subject. You can combine it with the specific substance term you are interested in
- Citations indexed prior to 1996 do not routinely have a pharmacological action tied to them. (from question 11 in Q & A)
Here are a couple additional links that can be helpful when searching for Chemicals and Drugs:
Pharmacological action terms
http://www.nlm.nih.gov/bsd/disted/mesh/paterms.html
Searching chemicals and drugs
http://www.nlm.nih.gov/bsd/disted/mesh/drugsearch.html
From the Technical Bulletin:
PubMed® and the Expansion of Pharmacological Action Terms
http://www.nlm.nih.gov/pubs/techbull/nd07/nd07_pa_update.html