Why don't antibiotics work against viruses?
As some people have already said, antibiotics are designed to act on bacteria. Specifically, antibiotics tend to disrupt various functions within bacterium; for example penicillins contain a structure known as a β-lactam ring which inhibits the formation of bacterial cell walls. Viruses however, use the organelles of the host cell to reproduce, and as such do not have any internal functions to disrupt (they're just DNA/RNA fragments in a protein coat, and sometimes a lipid outer coat); thus they're not affected by antibiotics. Antivirals on the other hand tend to try to stop viruses infecting cells, reproducing within the cells, being released from cells, or stimulate the body's immune system.
How long does it usually take for antibiotics to start working?
Anti biotics are a big group of drugs.if you have infection of upper respiratoy tract and fever,doctor will prescribe you antibiotics.most of the times these ABS are broad spectrum(will be effective against multiple types of bacteria which usually are seen in these patients).Getting culture is tedious,costly and time consuming(min 48 to 72 hours).surely you would not like to suffer for another 2-3 days waiting for the culture report.further growth characteristic pattern and drug sensitivity may be different in vivo and in vitro.therefore it is only practical that doctor prescribes you medicines in standard doses according to your clinical presentation.there are many factor which can change bioavailability of drug(as described by other author).however most of the standard regimens ensure that adequate drug level is reached within a day or two.by this time clinical response will be evident.please note that many a times upper resp infection is due to viruses(like influenza virus,swine flu etc).ABS are not effective against viruses.In case of respiratoy distress and non responsive ness to treatment please get the test for swine flu(in view of recent epidemic).Most other virus inf are self limiting.giving ABS will prevent secondary bact inf.
Why can’t antibiotics get rid of viruses?
Antibiotics work in very specific ways. They tend to exploit the differences between a bacterial cell and a human cell and kills (or inhibits) the bacterial cell on that basis.For example, penicillins and cephalosporins work by stopping bacteria from making a cell wall that it needs to survive. Humans don’t have cell walls so our cells aren’t affected. Aminoglycosides, tetracyclines, and macrolides work by binding to bacterial ribosomes which would stop them from making proteins that they need to survive. Human ribosomes are shaped very differently than bacterial ones, so we’re minimally affected by these antibiotics.When it comes to viruses, they don’t have cell walls, they don’t have ribosomes, and they don’t have any of the things that antibiotics target. Like I said, antibiotics were specifically discovered/created to attack bacteria, which have features that are not present in viruses, so there’s no way that antibiotics could work against viruses.Viruses are much more sneaky. They work by getting inside a human cell and uses the human machinery to replicate and spread. So it is quite difficult to develop some form of antiviral that doesn’t affect human cells as well. If you want to make an effective antiviral, you must find some difference between viruses and human cells to exploit. Different antivirals work in many ways. One of them works by attacking the molecule that allows viruses to leave the cell (neuraminidase inhibitors such as Oseltamivir) so that they can’t spread. Another type tries to prevent viruses from making copies of itself in a human cell (kinase inhibitors like acyclovir). They’re not as effective in treating viral infections as antibiotics are in treating bacterial infections.Like another answerer mentioned, if you get a viral infection, please don’t go for antibiotics. Not only is it a waste of money, but overusing antibiotics unnecessarily could breed resistant strains of bacteria. This means that antibiotics may not work when you actually need them to fight bacterial infections.The best way to prevent many viral infections is through vaccination. So take that flu shot every year, make sure you’re up to date with all your shots (measles, mumps, rubella, varicella, Hepatitis B etc…) to save yourself from potentially nasty infections.
Why are doctors so against antibiotics?
I have been sick for about 3 months. First I had a sinus infection then it became bronchitis. The doctor refused antibiotics and gave me an inhaler. The inhaler didn’t help at all. I coughed for 5 weeks - saw doctor again and she gave me prednisone. Again no antibiotics. She didn’t take any cultures. The prednisone stoped my cough but I still felt sick. Then I got another upper respiratory infection. I went to doctor - she did an X ray - I was clear but she refused antibiotics. It’s now another month and I still feel crappy. I spoke to doctor on phone and she said I may have allergies which I highly doubt it. Has anyone’s doctor refused antibiotics?
When should you give antibiotics?
I was talking to a friend of mine and i told her what we did when my baby was sick. well, she told me that i was very wrong giving him antibiotics. But i was told by my doc that we had to do so. pls let me know how to do you normally cure the cold & flu & viruses if the baby is under 1year. also, i once i read somewhere but cannot find anymore that the temperature is more dangerous to a baby than an antibiotics & that the high temperature could lead to delay of baby development. is it true or is it all myth? also at what temperature you should start giving medicine? thanks you
Does antibiotics make a cold/flu worse?
So, about a week ago, I got a really bad UTI (blood in my urine) and my doctor gave me antibiotics for the infection. Well a couple days ago, I got a cold, and it just keeps getting worse. My pharmacy said I could take Nyquil with my antibiotics, (no contraindications) so I started. Well, I've been taking it for a couple days, and if anything, my symptoms are worse. Friday I had a stuffy, runny nose. Saturday I started coughing on top of the runny nose. Yesterday, I started having pain in my lungs, and the coughing and nose issues got worse. Today, I'm nauseous, have the runs, on top of everything else, and I just can't stop coughing, sneezing and draining. Could the antibiotics be making me worse? I know that antibiotics kill good and bad bacteria...
Why antibiotics are effective against bacteria but not viruses.?
You first have to realize that anitbiotics usually work by targeting some necessary life process that goes on within a cell. It could protein production (aka Translation), it could target gene expression (aka Transcription) or other processes like membrane and cell wall production. These are by far the most common targets for antibiotics (with protein production and cell wall production making up the biggest bulk of the targets.) As far as viruses go, you have to realize that viruses don't do these things on their own. So you can't target something that doesn't exist in the agent you want to fight off. You see viruses are obligate intracellular pathogens. Which means that have to invade a living cell in order to reproduce. Because viruses don't have the machinery to make their own proteins or transcribe their own genes they have to hijack the machinery of the cell they infect to do it for them. This should make it easy to understand why we can't developer antiviral medications that work the same way antibiotics work to help rid our bodies of viral infections. If we develop a drug that stops viral protein production, because it is using the same machinery we normally use, we would in effect be killing all our cells, not just the ones that have viruses in them. These types of drugs would be way to toxic to our healthy cells. You might ask yourself, well then why do antibiotics work on bacteria if they are targeting processes inside of bacteria that we need to do also (ie. protein production or cell membrane production)? The answer to that is evolution. Enough evolutionary time has passed that the processes we use to do these things aren't similar enough to cause cross reactivity. As time passes, things change. That's the basis for evolution. The longer two organisms have time to diverge from one another the more able researchers are able to use those differences to treat if one chooses to. In the case of bacteria. We can take advantage of the differences between them and us to get rid of them if they infect us.
Symptoms are still present after taking antibiotics for 2 weeks, what should my friend do?
Antibiotics can only cure bacterial infection so if your friend suffers from a virus its perfectly understandable that the antibiotics didn't work. A viral infection has to be eliminated through the body itself but he can stock up on fresh garlic and bunches of it it can kill the virus. So chopped up garlic about 5 cloves taken thrice daily on a sand which or with food. Multivitamin supplementation will also boost the immunity along with the garlic to eliminate the virus much quicker. Also keep in mind every single time one takes a set of antibiotics you have to finish the whole set so as not stopping after symptoms have improved. That and secondly with every time you use antibiotics you must consume natural yoghurt such as Bulgarian or Greek as to replace the good bacteria to your gut. Antibiotics destroy both the bad and good guys and that alone can trigger much worse illnesses in future so remember those two tips.
Why do doctors prescribe antibiotics for viruses/viral infections?
This is an interesting question, and I will discuss further, but the main answer is doctors don't prescribe antibiotics for colds. You are correct, a cold is caused by a virus.Unfortunately, the patient does not come in with a tattoo on his forehead that says, I have a cold.When I was in medical school, I had a severe bronchitis, and probably pneumonia. Dutifully I went to the doctor that treated the med students. Of course, he was our Statistics teacher. Suffice it to say he was not very good at that either.Long story short, he made me culture my sputum 3 times, which took 6 days, before he would give me antibiotics. I literally almost died. Probably survived only because I was young. 3 times the cultures grew out pure H. Influenza (a bacteria).After I recovered, my friend developed my same symptoms. He asked me what I took, got a prescription, and never even got sick.As a resident in OB/Gyn, I noticed when someone was very ill, we got blood cultures before treatment. Cultures took two days. By that time, they were much sicker.Today, doctors do not hesitate to use triple antibiotic therapy for someone with a serious infection. They do not wait for blood cultures.What did I learn from this? When I was practicing medicine, and developed green or yellow sputum, I treated myself. I could not afford to miss days in my practice. If I did not work, I did not get paid. I am amazed that Bob Costas did not get treatment for his conjunctivitis when he was hosting this last winter Olympics. He kept saying, the doctors told me it would go away. It did, but a week later. How much money did he lose? Personally, I would have treated him and it would have gone away in a day.In summary, if I get a cold I don't treat it with antibiotics. But if I am not sure, I treat it. Every day is important to me, and if I don't have to be sick I choose not to do so.One does not have to use the "big guns" of antibiotics that are available for very serious infections. We should save these. But Doxycycline and Erythromycin can be judiciously used. Antibiotics, when used early in an infection, can prevent it from becoming more serious. This is especially true in Mycoplasma infections, where early treatment can knock it out quickly, but if not treated, it can last for months.If you are the CEO of your company, and can't miss work, I would take the antibiotic. Even though most doctors would disagree with this philosophy, you can bet they are treating themselves when they get sick.