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Are drugs tested on animals and human cells for safety?

Or is it also effectiveness? Would appreciate somebody clearing this up for me thanks :smile:
Original post by azo
Or is it also effectiveness? Would appreciate somebody clearing this up for me thanks :smile:


This Wikipedia page gives a brief overview of the whole drug development process. Animal testing is used for the purposes of safety, efficacy (effectiveness - does it do what you expect it to do), and figuring out what happens to the drug once it's in a living subject (how long does it kick about for, how is it broken down, how long until the breakdown product is excreted, does the breakdown product do anything crazy...). Safety is the main focus of the early phases of clinical trials; efficacy is the main focus of the later stages. But information is gathered on all topics at all stages. :smile:
Original post by The Moo
Drugs are tested for efficacy, toxicity and optimal dose.


We can't really test dosages on animals due to pharmacokinetic differences. That sort of study is reserved for early phase human trials. :smile:
Hello

I have a 1st class masters in pharmacy.

The major reason drugs are tested on animals is for a thing we call 'proof of concept.' Basically, we genetically modify or breed a strain of say mice, that is prone to a disease state. This disease state is as close as we can match it to human disease. For example, you might breed diabetic mice, then test a new antidiabetic compound on them. If it seems to improve the diabetes, then you have proof of concept.


Other conditions are harder to replicate, such as depression or other mental disorders. After all, how can we replicate complex diseases in the brains of less complex organisms? How can we know truly when they are depressed?


Other reasons we might use animals is to see how the drug is metabolised. Major side-effects may be evident early on. Poor absorption of the drug, or toxicity would also become evident at an early stage,too.


Things such as dosage finding (that means finding the effective dose in humans) happens in human trials later on.

Animal testing is not so useful or as common as people seem to think. Other much cheaper and more effective alternatives now exist; Most involve human cell cultures in 3D micro-environments, such as pancreatic cells in a hypoxic chamber to study pancreatic tumours. These sort of set-ups better mimics cell-to-cell behaviour and disease conditions. Cell cultures are very useful for testing how well cells absorb a drug, since drug absorption is one of the major reasons new drugs nevergo beyond this initial testing phase. We also use cell cultures to examine drug-targeting; this is a clever way of getting the drug to the desired location within the body. For example, some cancer cells express certain receptors on the surface in high numbers. Drugs can be attached to antibodies, that are then attracted to/attach to these surface receptors. In this way chemotherapy drugs can attack cancer cells, leaving healthy cells alone. All this can be tested in cell cultures.
(edited 9 years ago)
Refer to Liquidcherry's post ^.


Worth noting that there is a not insignificant amount of publication bias in medicine especially surrounding drug trials due to the money involved. This doesn't mean they arent safe, it just means the certainty of just how safe they are and under what conditions is sometimes questionable.

This gentleman covers some of it in this ted talk.

http://www.ted.com/talks/ben_goldacre_battling_bad_science
Original post by Amphiprion
Refer to Liquidcherry's post ^.


Worth noting that there is a not insignificant amount of publication bias in medicine especially surrounding drug trials due to the money involved. This doesn't mean they arent safe, it just means the certainty of just how safe they are and under what conditions is sometimes questionable.

This gentleman covers some of it in this ted talk.

http://www.ted.com/talks/ben_goldacre_battling_bad_science


There is some drug bias, but this is what pier-reviewed journal publications are for. Most bias can be picked out in statistics. It must be added that drugs take 15-20 yrs to reach the market and cost millions to develop. Trials are not taken lightly, and in England, the MHRA decides which drugs get licences and which don't. The system is inspected vigorously, and the PSNC continue to monitor drugs and medical devices, as do NICE for efficacy and value. No singular body has over-all control, and drug companies can not hide or manipulate data easily. Even once on the market, post-clinical trials continue. Further restrictions for the drugs use can be applied by Governing bodies, and drug companies must comply with these regulations. Drugs may also be withdrawn, either by force or the drug company can do so voluntarily. For more info, go to the MHRA website.

But this is a tangent. ;D
Original post by LiquidCherry
There is some drug bias, but this is what pier-reviewed journal publications are for. Most bias can be picked out in statistics. It must be added that drugs take 15-20 yrs to reach the market and cost millions to develop. Trials are not taken lightly, and in England, the MHRA decides which drugs get licences and which don't. The system is inspected vigorously, and the PSNC continue to monitor drugs and medical devices, as do NICE for efficacy and value. No singular body has over-all control, and drug companies can not hide or manipulate data easily. Even once on the market, post-clinical trials continue. Further restrictions for the drugs use can be applied by Governing bodies, and drug companies must comply with these regulations. Drugs may also be withdrawn, either by force or the drug company can do so voluntarily. For more info, go to the MHRA website.

But this is a tangent. ;D


Tangent indeed but mildly relevant I don't feel that guilty :cool:

I agree with you but the publication bias is a first step towards the ocasional slip up in accuracy of justification of certain things in medical science. It doesn't always lead to the green light for a drug for example but it can be part of the process. I've a lot of experience with stats analysis, I'm no absoloute expert but I know enough to confidently say that stats can be manipulated to produce what you want to show, especially if you just tweak the data before even running the analysis; People do tweak data in science, all the time. Especially under/post-grad, arguably not "professional" science but the time I've spent with "professional science" has left me very skeptical indeed.

There was something else I was going to say which I feel like was probably a key point and I've forgotten. Derp!
Original post by Amphiprion
but I know enough to confidently say that stats can be manipulated to produce what you want to show, especially if you just tweak the data before even running the analysis; People do tweak data in science, all the time. Especially under/post-grad, arguably not "professional" science but the time I've spent with "professional science" has left me very skeptical indeed.


Quite so, it does indeed happen. But part of any good degree teachers budding scientists the importance of stats. I criticised several articles in my 4th year dissertation for using inappropriate statistical methods to boast significant results. A good scientist is always pessimistic, and can read between the lines to reach their own conclusions from the data. Conclusions that exaggerate findings are also common. But getting published in science journals is such a task, every article seems to hype up their findings as the new best thing to be discovered since fire.

Anyway,I'll stop there for tonight 8) +1 thumb up for you.
Original post by LiquidCherry
Quite so, it does indeed happen. But part of any good degree teachers budding scientists the importance of stats. I criticised several articles in my 4th year dissertation for using inappropriate statistical methods to boast significant results. A good scientist is always pessimistic, and can read between the lines to reach their own conclusions from the data. Conclusions that exaggerate findings are also common. But getting published in science journals is such a task, every article seems to hype up their findings as the new best thing to be discovered since fire.

Anyway,I'll stop there for tonight 8) +1 thumb up for you.


Can't +1 you cause I did your other post but agreed again.

There is two types of published science in the world. True science and wild hyperbole. Wild hyperbole is a favourite of mine in making the significance of my dissertation project look far more important than it is. Never ending cycle!
*rolls up revision sleeves*

*digs out preclinical development lectures*

I'm only in my second year so take this with a pinch of salt, but from what I recall (and I hope I remember better in the exam!), animal testing tends to have a role in looking at the pharmacokinetics of a drug, and especially how it's metabolised in vivo. It's all very well if it works in a test tube in a lab, but you need to know whether it'll work on a living thing. Sometimes animals are used for this, but since the animals used in labs have to be specially bred for the purpose, they're more expensive than hiring the researchers themselves (if I heard my lecturer correctly), as LiquidCherry said, where it's possible not to use animals, they don't. If I remember rightly I think safety and efficacy tests are performed on both animals/cell cultures and then later in healthy human volunteers, before moving onto tests with patients who actually have the condition. Animals are also sometimes used to look at the function of different genes, to help identify possible targets for drug development. Like if you knockout the leptin gene from a mouse it doesn't know when to stop eating.

Also tests on the effects of drugs on pregnancy and lactation are done solely on animals, not humans, if they're done, you can't test on pregnant women. So in that sense it's used to check whether a drug would be safe in pregnancy, and that'll appear in the literature allowing healthcare professionals to make a judgement on whether or not they believe the benefit of taking a particular medication outweighs the risk. Obviously there are some we know cause definite harm to the foetus, thalidomide being the most famous example, and a few medicines that are so old that they've been used in pregnancy before and haven't given any ill effects.

I hasten to add that this is all rather sketchy knowledge and it's mostly me trying to regurgitate lecture notes as a vain attempt at revision.

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