Pharmaceuticals: unknown mechanisms?

[Californium]

Hi - first post, and I was hoping some practicing clinicians/scientists might be able to advise.

 

I've heard that in the odd case a drug may be approved for use where the precise mechanism for its efficacy is not known. I am guessing that this is because they are shown to be effective in clinical trials for certain conditions despite such a 'gap' in knowledge? Can anyone provide examples of such cases, and where I might be able to find out more? I am interested both in the circumstances around their discovery, as well as the criteria via which drugs with unknown mechanisms are approved.

 

I should point out that I am not scientifically trained (I'm a layman!), although I do have an interest in the philosophy of science, and this area in particular interests me.

 

Thanks in advance for any response.

[jake.com]

http://www.nytimes.com/2009/09/25/health/research/25aids.html?_r=1

 

Is this any help?

[Mr Skeptic]

Well it doesn't really matter if the mechanism is known, only that the medicine works. For example, it is highly unlikely that anyone knew exactly how Penicillin killed bacteria (it prevents them from forming a cell wall), but knowing that it did and was mostly safe was good enough for it to be used everywhere.

[Californium]

Hi jake and Mr Skeptic - thank you for the responses.

 

That article is interesting, it looks like an example of the thing I am getting at. I wondered if there are any cases explored in depth in either medical literature or the philosophy of science? I will do some online research around the historical discovery of penicillin also.

 

Thanks for replying.

[zule]

Aspirin has been widely used since the first of the 20th Century. However, its basic mechanism of action was not discovered until the 1960s.

[psynapse]

Disease-modifying antirhematic drugs (DMARDs) is a class of drugs which are unrelated except that they have been found to treat rheumatoid arthritis. These drugs are by and large discovered by chance.

 

Essentially what happens; a patient with rheumatoid arthritis is prescribed a drug for an unrelated condition to thier arthritis and notices alleviated RA symptoms. The doctor may conclude that the drug does treat RA.

 

The mechanism for the drug may be well established for what it is specialized for, but will also begin to protect bone and cartiledge in patients with RA with unknown mechanisms. The symptoms are not merely masked but RA will actually begin to reverse, hence, "disease modifying."

 

If you want to know more about this class of drugs:

http://en.wikipedia.org/wiki/DMARDS

[Horza2002]

Aspirin has been widely used since the first of the 20th Century. However, its basic mechanism of action was not discovered until the 1960s.

 

I'd also like to point out that the ancient Romans noticed that when you had a headache and sucked the bark of a willow tree, the headache went away. That is because willow bark contains salalic acid. Aspirin is the methyl ester of salalic acid... so its been around for a long time!