Where can i find an efficacy comparison of old drugs vs new drugs?
March 26, 2010 8:15 PM   Subscribe

The fact that drugs aren't marketed as being x% more effective than another drug makes me more than suspicious. Where can I find comparison information of old vs new drugs? new vs generics? I'll give you an example. I have allergy problems. Doctors try to tell me about the latest xyz antihistamine. These doctors are paid by the drug companies to sell me this stuff, and can't seem to give me any apples to apples comparisons. Is allegra more affective than diphenhydramine? Is x more affective than y? Were the best drugs already found, and the newer drugs crappier, or is it the other way around, or neither? Why isn't this openly published and available? What the hell happened to the scientific method?
posted by torpark to Health & Fitness (22 answers total) 6 users marked this as a favorite
The reason they don't say "X% more effective" is that it is impossible to quantify it that finely. Also because different people react differently to different drugs. A new one may be a miracle for one person and may not work at all for another.

Drug companies can only say things they've previously proved to the FDA through huge and expensive testing.

These doctors are paid by the drug companies to sell me this stuff...

That's raving paranoia.
posted by Chocolate Pickle at 8:19 PM on March 26, 2010

Why isn't this openly published and available?

It is, kind of. PubMed lets you search for studies. At the very least you'll get a citation for chasing down the full text at a library, but usually there are also abstracts with the basic information (e.g., "in conclusion drug X is better than drug Y for condition Z"). Sometimes the full text of the study is available online.

Some journals, such as the British Medical Journal, make all but the most current issues available for free online. Others, like many of the Public Library of Science journals, make articles available for free as a matter of course.
posted by jedicus at 8:20 PM on March 26, 2010

The thing that you're looking for is called comparative effectiveness research. I'm linking to Google rather than to a particular article, because lots of people have lots of different things to say about it.

What the hell happened to the scientific method?

It's not in the interest of the drug companies.

That said, the health care reform bill that just made it through Congress contains a bunch of funding for it, so you should expect to see more information like this in the years to come.

For drugs it certainly makes sense. For aspects of clinical practice it is apparently more controversial. I've heard that clinicians consider it an ivory tower pursuit that is disconnected from the actual practice of medicine.
posted by alms at 8:21 PM on March 26, 2010

The reason they don't say "X% more effective" is that it is impossible to quantify it that finely. Also because different people react differently to different drugs. A new one may be a miracle for one person and may not work at all for another.

Drug companies can only say things they've previously proved to the FDA through huge and expensive testing.

This is misleading. It is certainly possible to compare the effectiveness of different prescription drugs, and it's often possible to do so quite accurately. Drug companies love this when they come out on top and they go to great lengths to avoid it if there's a chance to come out on the bottom. It costs money, sure, but it's not outside the range of what drug companies could very easily afford. But as often as not it's not in the interest of their bottom line.
posted by alms at 8:23 PM on March 26, 2010

drugs affect different people at different times, even. for instance, specifically related to allergy medicines - claritin used to be the only thing that worked - then 3 months ago, POOF it no longer worked. now i'm on zyrtec - works like a dream, when before it didn't work at all.

as far as generics - the amount of drug in your name brand is posted on the packaging, the generic should match it exactly. if they both have the same mg of the same active ingredient, then buy the generic.
posted by nadawi at 8:24 PM on March 26, 2010

These doctors are paid by the drug companies to sell me this stuff...

That's raving paranoia.

Then what's this all about?
posted by lhude sing cuccu at 8:28 PM on March 26, 2010

Drug manufacturers sponsor studies all the time. Obviously they sponsor the trial studies for FDA approval, but they also sponsor studies comparing their products to other products quite regularly. Now, of course, these studies are often suspect in terms of methodology; classic examples include comparing their drug to a weak dose of the competitor drug and looking only at secondary markers (e.g. "reduction in cholesterol levels") rather than outcomes (e.g. "reduction in heart attacks or deaths"). But the studies are done all the time.
posted by jedicus at 8:28 PM on March 26, 2010

The problem is as others have noted that it is not in drug companies' interest to conduct those studies, and they are not required to do so.

The FDA only requires that they show that their drugs work better than placebo for approval purposes. Nevermind that when there is already a decent drug for the problem, comparing something to placebo probably isn't very relevant to most people...

Recommended reading here and here

you are right to be suspicious of people who push the 'latest' medicine. unfortunately, the drug companies have the money and the power. It is hard to conduct studies such as the ones you want without money and power. really the only ones who can do it are the government, and they are short on cash these days... in the meantime, you are lucky if your only dilemma is Benadryl vs. Allegra. Neither one is probably going to change your life much. Just take whatever works for you cost wise and personally.
posted by treehorn+bunny at 8:35 PM on March 26, 2010

If you want to avoid abuse by pharma companies, you should also really understand Number Needed to Treat.
posted by alms at 8:50 PM on March 26, 2010

What you need to google: "Comparative effectiveness." There's very little public research into comparative effectiveness of different treatment methods right now, but a lot of money has been allocated to begin this process in the U.S. through the federal stimulus bill and the new health care bill, but it will still be years before good, comprehensive data emerges.
posted by croutonsupafreak at 8:54 PM on March 26, 2010

there was a study i read about a while back where they tried to figure out how susceptible doctors were to the influence of advertising, particularly drug ads in medical journals. answer: very. turns out, doctors are just as obsessed with the 'new' as the rest of us, and often prescribe drugs they know little about outside of what they've been told in the bold type of a 'big pharma' advertising campaign. whatever, they're only human.

however, there is a place to check out (though i forget exactly where), i read about it a few years ago and it has "comparative effectiveness" written all over it. it's a nursing website. specifically a nursing community website where nurses compare notes on various treatments, as they often have more contact with the patients, and therefore a better view of the results. it was getting a lot of praise in the medical community at the time IIRC...does anybody know what website i'm talking about? (YMMV, though, as allergies and their treatments or generally more of an 'outpatient' thing)
posted by sexyrobot at 9:11 PM on March 26, 2010

Someone has to pay for studies. People who have money pay for studies. People who have new, patented medicine have money to pay for studies. Surprisingly, they never pay for studies showing they drug they spent millions developing is better or worse than the old one that is no longer in patent. They just fund studies to show it is safe and effective.

Always ask your doctor if there are generic equivalents you can try. Even if it isn't as effective in general, it may be more effective for you personally.
posted by chairface at 9:27 PM on March 26, 2010

Not to poo poo what has been said above as most of it is true, but there are many more practical and less nefarious reasons why trial sponsors would prefer to compare a drug against a placebo over a competitor. If the competitor already has good data demonstrating efficacy, this means that for any given effect of a new drug of interest, the magnitude of the difference between this drug and placebo should be greater than that between the drug and its competitor. Why is that important? Because in order to design a trial powerful enough to detect these things with statistical significance, you will need more patients for the latter study than the former. That means more resources will be required. Now if a drug yields remarkably good results against placebo or has very impressive preclinical data, sponsors may choose to take a chance and commit the resources to a drug comparison.

The scientific method is alive and well, but money doesn't grow on trees and pharmaceutical companies aren't philanthropic agents.
posted by drpynchon at 9:49 PM on March 26, 2010 [1 favorite]

I have severe allergies. Claritin works great, until I build up a resistance, and then I have to take so much the side effects become worse than the allergies. So, I switch to Zyrtec or Allegra for a while - and they don't work quite so well, but will do the job, maybe, until I can switch back.

Sometimes, I take benadryl. That works awesome - It will absolutely alleviate all of my symptoms - except it also turns me into a drooling doorstop. Those are the days I call in to work, pop a couple, and crawl into bed and pray for death or the medicine to act, whichever comes first.

The point I am trying to make is that oftentimes it becomes more about side effect management than symptom management. So, the efficacy of a drug is sort of less important than the cost involved in taking it.

The side effects of a given drug are highly individualized. So, mostly, using drugs to treat something on a particular person is sort of guesswork. This is particularly true with allergy meds, in my experience.

As for generics - they are the same drug. It's the suspension that is different. Just like generic Fruit loops dont hold a crunch the way real ones do, generic drugs (generally) don't last as long or have as continuous a dosage as the more expensive varieties do. Sometimes this doesn't matter much, other times it matters a great deal.

It is true that drug companies exist to make money - but they aren't going to sell something they know doesn't work. Your doctor wants you to not suffer, too. And they understand, better than most, that it might take some experimentation to find what works for you. And then you'll age, or start eating different, or something; and it will all change anyway.

It's fruitless to look for some large conspiracy to deprive you of your bodily fluids. Mostly, it's just people trying their level best to deliver state of the art technologies in the hopes of making your life better. The catch is that the state of the art totally sucks right now. But, then, it's a million times better than it was 20 years ago (let me tell you!) , and that was a million times better than it was 20 years before that.

I feel your pain on the allergy meds though. It's been 25 years of shots, and drugs, and inhalers and this and that and the other, and my allergies get worse every few years. So it goes. The drugs we have now work better and with fewer side effects - but they are not perfect and won't be for a very long time. You'll have to find a strategy that works for you and be open to changing it as you and your environment change. It sucks, but at least it isn't cancer or aids or some other problem.

Keep your head up and take care of you. Don't worry so much about the "drug companies". If you find something that works for you, use it until it doesn't work then do something else.
posted by Pogo_Fuzzybutt at 10:16 PM on March 26, 2010

You get x% from clinical trials, which are highly selected populations. The risk-reward benefit to you personally may be quite different than the people enrolled into the trial.

As a fictionalized example, say the first big trial of vioxx was in young people with ulcers. Vioxx is a pain med that probably increases your risk of having a heart attack but decreases your chance of having aggravated ulcers (which people bleed to death from). If you're a young person (low chance of heart attack) with existing difficult ulcers (high chance of aggravation), you're x% better off taking vioxx. Taking that x% and putting it on TV would be completely misleading because more people are in the opposite situation: they're old with hypertension and diabetes so they have a huge risk of a heart attack. They would be much worse off taking vioxx.

Summary: x% doesn't exist for everyone, which is why they tell you to ask your doctor. MDs are (mostly) not systematically bribed to give you expensive shit in exchange for a $.02 pen.
posted by a robot made out of meat at 5:59 AM on March 27, 2010

Percent effective would be irrelevant, because different drugs have different side effects, methods of action, contraindications, etc. To use your allegra versus diphenhydramine example, while both might stop a seasonal allergy attack equally well (hypothetically, I don't know whether this is true), diphenhydramine causes so much drowsiness that it is often used as a sleep aid! Furthermore, people like me can't take it because it aggravates Restless Leg Syndrome, something I learned the hard way. On the other hand, an individual might be allergic to any of the active or inactive ingredients in allegra, and therefore prefer claritin or zyrtec. Drugs that aren't the same chemical structure won't do the same thing in the body. So, it would be MEANINGLESS to tell me, hypothetically, that "Diphenhydramine is 8% more effective at relieving itchy eyes in allergy sufferers," without warning me that I can't take it because it will make me drowsy and unable to function, but aggravated by leg spasms.

Furthermore, keep in mind that in at least some cases the 'new' drugs are vastly superior to the old ones. If you doubt this, read up on MAOIs versus Tricyclics versus SSRIs for depression. MAOIs were generally effective, but not well-tolerated. They have an enormous amount of drug and food interactions - have you ever read the back of an OTC pill bottle? Most say you can't take them if you are on MAOIs. You also can't drink red wine, eat chocolate or eat certain cheeses. These problems were relieved to some degree with second-generation Tricyclic Antidepressants (like Elavil) but were more or less completely eliminated with the much more recent SSRI Antidepressants (like Zoloft, Prozac, etc.). Now there are still some people who need the older versions of the drugs, but for most people, the newer versions have been a godsend.

When your doctor recommends the next big thing to you, just ask why. It's not a fucking conspiracy. If you don't understand the differences between the drugs, or why one is being suggested over another, just ask. Doctors are not great communicators, and they may not give the information unless prompted. I sat in a Doctor's appointment in January, where we weighed the pros and cons between 3 different classes of drug to treat a problem - all of which would have resulted in prescriptions for GENERICS. All you need to do is take responsibility to get a little bit more informed from your doctor. Or from the internet and so forth, because this info is definitely available. Perhaps the Big Pharma Conspiracy theorists just shout louder.

If the above is tl;dr, then: Apples to apples comparisons aren't an effective descriptor of the differences between potatoes and pineapples.
posted by bunnycup at 7:30 AM on March 27, 2010

Another consider in direct to consumer ads is that clinical trial results are complicated. Do you know what a hazard ratio is? How should you interpret different endpoints and time courses? Does your grandma know this? There's little value in placing it in an ad.
posted by a robot made out of meat at 7:34 AM on March 27, 2010

There was some research done a few years ago about improving the interpretability of drug ads. One concept that was introduced was the Drug Fact Box, a really easy-to-understand summary of the drug's pros and cons, which proved to be infinitely superior to the pages of fine print that one otherwise gets...

That said, the information's out there. As mentioned above, one of the major problems is that drug trials determine an average effect in a particular population, which may or may not translate to the same effect in you, the individual patient. I don't know of many too many sources of consumer-directed comparative drug information, but for professionals, The Medical Letter can be very helpful, as can RxFiles.
posted by greatgefilte at 7:47 AM on March 27, 2010

Every time you take a drug you're acting as a guinea pig. Studies can generalize how most will respond to any given drug, but you may not react the same way.

new vs generics?

May or may not be helpful, but there's a publication called, Approved Drug Products With Therapeutic Equivalence Evaluations, which lists which drugs are interchangeable.

If you doubt this, read up on MAOIs versus Tricyclics versus SSRIs for depression.

All three classes of drugs act differently on the brain, its a bit like trying to compare acetaminophen, acetylsalicylic acid and an anti-inflammatory then concluding one is hands down better than the rest. The problem with two of those three anti-depressants is compliance with a diet and/or the risk of overdosing which is why doctors embraced SSRI's initially. SSRI's reduced those risks, but whether they are more effective because they're newer is really debatable.
posted by squeak at 8:33 AM on March 27, 2010

Most drugs on the market, when taken as prescribed, are effective in 30-50% of the population.

That image is from Melody Petesen's book Our Daily Meds. Bill Moyers interviewed her on her book for his program.

Modern pill-based medicine is run by the corporate marketing departments, not the doctors or the scientists. And you should ask your doctor if they have any particular financial incentive to prescribe a particular medicine.
posted by Pirate-Bartender-Zombie-Monkey at 10:03 AM on March 27, 2010

The problem is as others have noted that it is not in drug companies' interest to conduct those studies, and they are not required to do so.

It is if your drug kicks ass! A few companies ago I worked on a drug for the treatment of neutropenia which would have competed head to head with Amgen's Neupogen. We had bioassay data which suggested that our molecule was much more effective than Neupogen so either better performance or lower cost due to smaller required dose.

In the clinic we found that in real live patients it was not statistically different from Neupogen so we pulled the plug on the study. The thing to remember here is that not statistically different might mean twice as good for a lot of people, but the size and duration of the study needed to really prove that would have left us with a drug we had to charge a gazillion dollars a dose for to pay for the study and people would have just used Neupogen since it was so much cheaper.

Think about it this way: The data from a simple ELISA where there is one reaction going on and you can run dozens of preps with all kinds of conditions on the same microtiter plate is sometimes too noisy to give you a dependable answer. Oh well, throw it in the biohazard bin and coat a fresh plate for tomorrow.

Now imagine running the same experiment in parallel with an unimaginable number of other reactions because instead of putting 100 µg of drug to a well in a plate, you're putting it in someone's mom.

Then there is patient to patient variability and the fact that everything that we call, oh, diabetes isn't due to the same root cause. And for some diseases we're only guessing at the root cause.

Finally, there are a lot of things we could do in clinical studies that would make them more scientific, but we don't.
posted by Kid Charlemagne at 4:39 PM on March 27, 2010

as far as generics - the amount of drug in your name brand is posted on the packaging, the generic should match it exactly. if they both have the same mg of the same active ingredient, then buy the generic.

Generally true, but.... There was an article a while back (I may have read it here on the blue) where some generic company was doing a crappy job of their formulation so that while it contained the same amount of active ingredient, it's availability was all wonky and you got twice as much drug in the morning and none in the evening.

Also, I've seen some western blots for host cell proteins for various generic human growth hormone products as well as Nutropin (Genentech) and Genotropin (Pfizer). Wow! (And I don't mean that in a good way.)
posted by Kid Charlemagne at 4:55 PM on March 27, 2010

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