How do drugs work? Why do drugs have side effect?

[nec209]

If I understand drugs are small molecules that activates or inhibits target proteins and results in a therapeutic benefit to the patien.So why do drugs have side effects? Drug is small molecules that are shape of proteins of they interact and therefore will bind to it.So why are there side effects?

 

May be I'm confusing the future of target drugs with how drugs work?

 

One of the main problem with diseasees , illnesses and Chemotherapy is side effects.

 

And if I understand it is easy to make drugs , but very hard to make drugs that don't have side effects.

 

That take cancer for example , it is easy to come up with chemotherapy !!! But very hard to come up up with chemotherapy that works but does not kill you or make you very ill.

 

What all this talk of target drugs in future that only bind to the protein.

[CharonY]

First of all not all drug targets are proteins, nor are they super specific to only one target. Second, even they are, you have to remember that the protein/biomolecule target fulfills a normal role in your body. If you just inhibit/alter its function it will automatically have consequences.

Side effects are a misnomer, all of it are normal effects of inhibiting or otherwise altering the drug target. It is just not desirable.

[nec209]

First of all not all drug targets are proteins, nor are they super specific to only one target. Second, even they are, you have to remember that the protein/biomolecule target fulfills a normal role in your body. If you just inhibit/alter its function it will automatically have consequences.

Side effects are a misnomer, all of it are normal effects of inhibiting or otherwise altering the drug target. It is just not desirable.

 

Why is not all drugs are specific target ? Is that not the holy grail of target drugs? Of hopes in the future to find target chemotherapy that only binds to that protein?

[lamironi]

Many people who take a drug have no side effects. Likelihood of side effects may be related to your age and overall health.

[CharonY]

All biochemical processes are stochastic. Few if any interactions in nature are 100% exclusively and is typically concentration dependent. I.e. at low concentration you have fewer interactions, at higher, you get more (typically). Higher specificity just allows things to happen at lower concentrations.

Drugs typically swamp your body to some extent (as it has go through bloodstream to reach your target area) and it tries to push levels down to your normal ones. As you can easily imagine it will not be the same for everybody and cannot be controlled that precisely.

 

But again, biological interactions are stochastic. The key lock image that some propagate at high school is simply not correct.

[nec209]

All biochemical processes are stochastic. Few if any interactions in nature are 100% exclusively and is typically concentration dependent. I.e. at low concentration you have fewer interactions, at higher, you get more (typically). Higher specificity just allows things to happen at lower concentrations.

Drugs typically swamp your body to some extent (as it has go through bloodstream to reach your target area) and it tries to push levels down to your normal ones. As you can easily imagine it will not be the same for everybody and cannot be controlled that precisely.

 

But again, biological interactions are stochastic. The key lock image that some propagate at high school is simply not correct.

 

sorry what do you mean by biological interactions are stochastic ( do you mean interacting with other systms in the body? If I understand drugs don't really work on lock image thing bind to only that target.Not sure how drugs really work but it does effects other systems in the body.If I understand target drugs are new thing and they hope in the future there will be more target drugs.

 

That take cancer , it is one of the hardest to cure because it like having a fish tank full of fish and trying to only kill the blue fish not the red fish.So you could add toxic or bleach but you kill every thing.Trying to get drug to only go after the blue fish is really hard.

 

They even have direct radiation these days but it is still not 100% direct and healthy cells get killed too.If the cancer is too big more areas of the body need radiation and collateral damage is too high and thus will cause the person to be very ill or die.

 

Other thing some cancers show symptoms in the first stage where it is easy to cure where other cancers only show in the later stage where it is much harder, because it's too big and collateral damage become too high.

 

Get any popular science magazine they talk in the future of more target drugs and way way way in future 50 years or more nanoprobes. I guess what I'm confused is how drugs work and how in future it will be more target drugs or why some drugs have less side effect than other drugs.

 

Other thing is some Chemo drugs they have now have less side effect and kill more cancer cells than Chemo drugs in the past and they keep looking for new Chemo drugs with less side effect and kill more cancer cells ,

 

I guess I'm confused about this 40% target ,50% target ,70% target and so on to hopes of close to or at 100% target of what really is going on chemistry and biology level.Of close to or at target drugs of the future.

 

It is very easy to come up with new drugs but it is really hard to come up with new drug that does not cause collateral damage or too much side effect.

Edited June 19, 2014 by nec209

[Bill Angel]

Some people suffer from auto-immune disorders. An auto-immune disorder is when a person's immune system attacks its own cells. Medications to treat this do so by suppressing the body's immune system. One side effect is that people with immune systems suppressed by these medications are more susceptible to infections like Tuberculosis, so they have to be tested for exposure to Tuberculosis every six months. Another side effect is when you get an infection that your body would normally clear up on its own, like an ear infection, your immune system can no longer accomplish this and a doctor has to prescribe antibiotics to get the infection cleared up.

I'm providing my own personal anecdotal experiences here from being on one of these drugs.

[nec209]

I think I may be confusing how drugs work with targeted drug delivery.

Quote

Targeted drug delivery, sometimes called smart drug delivery,[1] is a method of delivering medication to a patient in a manner that increases the concentration of the medication in some parts of the body relative to others. The goal of a targeted drug delivery system is to prolong, localize, target and have a protected drug interaction with the diseased tissue.

 

The conventional drug delivery system is the absorption of the drug across a biological membrane, whereas the targeted release system releases the drug in a dosage form. The advantages to the targeted release system is the reduction in the frequency of the dosages taken by the patient, having a more uniform effect of the drug, reduction of drug side-effects, and reduced fluctuation in circulating drug levels.

 

The disadvantage of the system is high cost, which makes productivity more difficult and the reduced ability to adjust the dosages.

 

 

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

 

And confusing this.

Quote

Targeted therapy or molecularly targeted therapy is one of the major modalities of medical treatment (pharmacotherapy) for cancer, others being hormonal therapy and cytotoxic chemotherapy. Targeted therapy blocks the growth of cancer cells by interfering with specific targeted molecules needed for carcinogenesis and tumor growth,[1] rather than by simply interfering with all rapidly dividing cells (e.g. with traditional chemotherapy). The term biologic therapy is sometimes synonymous with targeted therapy when used in the context of cancer therapy (and thus distinguished from chemotherapy, that is, cytotoxic therapy). However, the modalities can be combined; antibody-drug conjugates combine biologic and cytotoxic mechanisms into one targeted therapy.

Targeted cancer therapies are expected to be more effective than older forms of treatments and less harmful to normal cells

 

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

 

Getting confused and thus the confusion here in this thread.